The Dresden High Magnetic Field Laboratory (HLD) is a pulsed-field user facility which provides external and in-house researchers with the possibility to perform a broad range of experiments in pulsed magnetic fields [1]. Being a member of the European Magnetic Field Laboratory (EMFL), HLD provides access and supports more than 100 scientific projects annually. At the HLD, such diverse...
Fast ramping magnets are important accelerator components in several areas. In High Energy Physics they are needed in an accelerator ring for a Muon Collider, in booster accelerators for other colliders, and for production of high-intensity proton beams for high intensity targets. In the Basic Energy Sciences and the Department of Defense there is considerable need for intense levels of...
In the past 2 years SuperOx has invested significant resources into developing the next generation 2G-HTS wires for high magnetic field applications and created state-of-the-art production facilities in Japan and Russia, aiming at the fusion, MRI, accelerator magnets and motors markets.
Our current major product is based on the novel YBCO composition fabricated by PLD process on the...
The Laboratoire National des Champs Magnétiques Intenses (LNCMI) is a French host facility for experiments in high magnetic fields. LNCMI is a member of the European Magnetic Field Laboratory (EMFL) with the Hochfeld-Magnetlabor in Dresden (HLD) and the High Field Magnet Laboratory in Nijmegen (HFML). The Toulouse facility is dedicated to the generation of pulsed magnetic fields. It offers...
Recently, a domestic project for the construction of a 4th generation light source, Ochang Advanced Synchrotron for Industry and Science(OASIS), is embarked by the Ministry of Science and ICT in Korea. To increase the performance of the next generation storage ring, Seoul National University in collaboration with Pohang Accelerator Laboratory started a feasibility study on no-insulation(NI)...
Advancements in 2G HTS conductor performance continue to drive the operating limits for a broad range of demanding applications. The design, testing and fabrication technology of 2G HTS (RE)BCO conductors is presented, highlighting the ability of 2G HTS wire to function under a wide range of operating conditions. SuperPower continues to focus on process improvement to achieve high...
Driven by the 1.4 GW generator, the 60TCW magnet was the most powerful controlled waveform system in the world and had always been one of most important magnets to the NHMFL and high-field research community because of its following unique features: (1) quasi-static field up to 60 T with 100 ms flat-top and total pulse-length of 2000 ms, (2) variable magnetic field waveforms such as staircase...
High magnetic fields allow for the stabilization of otherwise inaccessible new quantum states of matter. A scattering technique is imperative for a deep and thorough microscopic understanding of these exotic high field phases in correlated electron systems. We report pulsed magnetic field installation for x-ray scattering experiments, aiming up to 60 T, within an international user consortium...
Design and fabrication of a new Nb3Sn-based superconducting undulator (SCU) are underway at the Advanced Photon Source (APS) of Argonne National Laboratory in collaboration with Fermilab and Lawrence Berkeley National Laboratory. This device will be installed on APS’s storage ring and will deliver a wide range of hard x-rays to APS users. To develop a robust and reliable fabrication process,...
At SuNAM, we set up a new RCE-DR(Reactive Co-Evaporation – Deposition and Reaction) system employing a 100 kW electron-gun for superconducting layer deposition. Using the new system, with higher power and enhanced beam stability, we co-evaporated APC generating materials such as Hf and Zr. We also tried rare earth(RE) elements other than currently used Gd, and mixtures of REs to get enhanced...
In recent years, a huge demand for HTS tape to be used in future commercial fusion reactors has emerged. High requirements on the mechanical properties and the tape performance in high magnetic fields for this market and other high-field magnet applications led to several developments at THEVA that are now transferred to regular production. Major improvements to the engineering critical...
We report on recent progress regarding the practical use and characterisation of fields in the 100-200T range with microsecond-duration at the LNCMI high-field magnet facility. Our Megagauss platform makes use of single-turn coils with 8-15mm diameter that are destroyed in the process, albeit with a close-to-100% chance of survival for scientific equipment in the bore. The setup permits...
The Fermilab Mu2e experiment is currently being built at Fermilab to search for evidence of charged lepton flavor violation through the direct conversion of muons into electrons. The experiment comprises three large superconducting solenoids; the transport solenoid consists of 52 superconducting coils arranged in an s-shaped pattern in order to guide muons from the source to the stopping...
We achieved both high electric conductivity and optimum strength in Cu-0.54Cr-0.046Zr alloy (wt%), and firstly characterized their properties at cryogenic temperature, which was comparable to those of Al60 both at 295K and 77K. Ordered clustering of solute atoms was revealed to be uniformly distributed in solution-treated samples. During deformation, those clusters became the heterogenous...
The critical current density (Jc(θ,B,T)) of ReBa2Cu3Oy¬ (ReBCO) coated conductors is essential knowledge for the safe design of high field superconducting ReBCO magnets. However, though the ReBCO windings in a real coil are oriented such that B is applied typically at a range of 0-18° from the tape plane depending on position in the winding, coated conductors are most often characterized with...
For high magnetic field, the pulsed magnets are normally designed with multiple coils. However, the magnetic field produced by the outer coil starts to drop at the moment when the inner coil starts working due to the electromagnetic coupling. Simulations show that the field drop is as much as 30% if the outer coil is driven by pulsed generator, with the result that the coil has to be designed...
A future accelerator facility to open up a new frontier will require a superconducting magnet with high radiation resistance. A construction plan of a second target staiton of materials and life science experimental facility is proposed as one of the future plans of J-PARC. At the facility, superconducting solenoids are placed just behind the target to maximize the production of secondary...
We have been developing the SCSC cable (or double “SC” cable, standing for Spiral Copper-plated Striated Coated-conductor cable), in which we wind copper-plated striated (multifilament) coated conductors spirally around a round core. In the SCSC cable, its spiral geometry decouples filaments against transverse AC magnetic fields to reduce its AC loss while the plated copper allowing current...
As a part of a conceptual design study for developing more higher magnetic field hybrid magnet, an outsert low temperature superconducting coils which can generate about 14 T magnetic field is being developed at the High Magnetic Field Laboratory of the Chinese Academy of Sciences. The superconducting outsert with a room temperature bore diameter of 1800 mm is composed of Nb3Sn coils and NbTi...
High current superconducting CORC® cable or wire is composed of spiraled HTS REBCO tapes in multiple layers. Multilayered CORC® wires can carry very high currents in background magnetic fields up to 20 T. The cable combines isotropic flexibility and high resilience to electromagnetic and thermal loads. The flexibility of the cable is limited by the critical strain value damaging the REBCO...
The cyclotron CYCIAE-100, the driving accelerator of the Beijing Radioactive Ion-beam Facility (BRIF), was completed successfully to provide up to 52 kW proton beams with energy range from 70 to 100MeV continuously for researches of nuclear physics, material and life science, also for medical isotope production in 2014. Although the design is ‘compact’, the total weight of CYCIAE-100 is still...
In this contribution the magnetic modelling and experimental validation of a superconducting degaussing system for maritime vessels is discussed. Degaussing coils compensate for the distortion in the earths’ magnetic field by the magnetized steel hull of a ship, thus rendering it ‘invisible’ for magnetic field sensors. Whereas typical power requirements with copper coils are of the order of...
A 12 T REBCO solenoid with a 192 mm wide inner bore tapes was designed in the framework of the BOSSE Project, using 12 mm-wide isolated tape as conductor. This 814 mm high coil can be used as a compact 1 MJ – 2 MW inductive energy storage, with an 850 A rated current. One of the objectives was to overcome the present record of mass energy density, held by a NbTi coil (13 kJ/kg), and reach 20...
The linear-motor type high temperature superconducting (HTS) flux pump is a wireless charger which can pump DC current into the second-generation (2G) HTS tapes without the physical contact. In addition ,the flux pump has the smaller volume than the traditional power supply for the same output current. So it is very convenient to charge HTS tapes by utilizing the flux pump which has a compact...
Abstract
A cryogenic permanent-magnet undulator (CPMU) with a period of 18mm and a magnetic length of 2m is being constructed for the Taiwan Photon Source (TPS). The CPMU with a gap of 5.5 mm can generate an effective magnetic field of 1.2 T at 150 K. When the field measurement, the temperature of hall probe will be drop at cryogenic temperature. Therefore, a field strength calibration and...
The flux pumping devices attract a lot of attention for the excitation of superconducting magnets or the compensation of the field decay. A carefully designed linear flux pump is presented in this work, the dimension of which is smaller than a 5 cm cube. The key part of the device is the magnetic circuit which guarantees the optimized flux pumping performance in terms of operation current,...
In order to enhance the quality of measurement results of a Physical Property measurement System using a superconducting magnet, spatially uniform magnetic field is required at the magnet center. However, measured field uniformity is usually worse than that of design result due to manufacturing errors of a magnet system. Therefore, spatial field uniformity compensation is needed to reduce...
The major difficulty of the quench detection of the superconducting magnetic system (SMES) is that the pulsating voltage of the converter is much larger than the local normal-zone voltage of the HTS coils. It is therefore difficult to detect the quench of the superconducting coil (SC) with the voltage measurement method. This paper presents a novel quench detection method without additional...
High temperature superconducting (HTS) magnets have many potential applications, for instance, NMR/MRI, levitation systems, and high field applications. HTS magnets require a constant external current source to operate in CC mode. Flux pumps provide an alternative contact-less charging source that can inject flux into a closed-loop superconducting circuit. The simplicity of the rotating type...
With the Meissner effect and flux pinning, high temperature superconducting (HTS) bulk can levitate with “self-stable” property above a magnetic guideway, integrating levitation and guidance functions in one. Generally, the propulsion function of an HTS maglev transportation is realized by another independent system, which has complicated the entire train system. Lately, according to the...
After completing the 32T all-superconducting user magnet, development of magnets of this class with a noticeably higher field has begun: the NHMFL 40T magnet is the immediate target. The next generation of high temperature superconductor (HTS) high-field user magnets demands the next generation of quench protection systems. Previously, a bank of batteries was employed to power the quench...
No-insulation (NI) winding method has been widely used in the fabrication of superconducting coils due to its excellent thermal stability and mechanical stiffness. In the NI coil, there is a charging delay and heat loss due to leakage current and metal insulated (MI) winding method has been proposed to reduce the charging delay and the heat loss by the leakage current due to the increased...
This paper studied the alternating current (AC) loss of stacked high-temperature superconducting (HTS) tapes based on the finite-element method (FEM). By solving the partial differential equation (PDE) of H formulation, this research analyzed the effects of the frequency, amplitude and phase of the current and magnetic field on the AC loss of the three-layer stacked HTS tapes which works under...
AC loss reduction in HTS coils can help reduce the cryogenic demands and increase the performance of HTS machines. In an HTS coil, most AC loss is generated in the end windings due to the large radial magnetic field in these parts. Therefore, one of the effective methods to reduce AC loss in HTS coils is using ferromagnetic flux diverters to reduce the radial components of the magnetic field...
Double pancake (DP) coils for a SMES coil have been developed using MgB2 Rutherford type superconductor. The DP coils are indirectly cooled in liquid hydrogen in order that the current carrying region such as conductors and leads cannot contact directly with the liquid hydrogen. However the cooling efficiency of the indirect cooling system is less than that of the direct immersed cooling...
Electric machines have been applied to every industrial and transport applications today and are required to realize high-output density.
Superconducting technology is one of the most effective methods for realizing the high-output density motors. The superconducting coils at ultra-low temperature can energize several hundred times higher current density in comparison with copper wires; it...
A 6.5 MVA/25 kV high temperature superconducting (HTS) traction transformer for the Chinese high-speed train was proposed in earlier works aiming to replace the oil-based transformers while achieve higher efficiency, lighter weight, and minimized volume. The high targeted efficiency of the transformer (> 99%) makes AC loss reduction a vital issue. HTS coated conductors generally exhibit...
Rare earth barium copper oxide (REBCO) coated conductors (CC) have high thermal stability and high current density. REBCO CCs are suitable for generating high magnetic fields. It is expected that magnets wound with REBCO CCs are utilized for high magnetic field applications, such as magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR), medical-use accelerators, and compact...
Superconducting materials have a high current-carrying capacity and direct current(DC) lossless characteristics. The linear-motor type flux pump is a wireless DC power source for high-temperature superconducting coils.In the control process of outputting DC current to the superconductor coil.Except for an uncontrollable parameter λ,which length is depended on the length of the teeth and slots...
The INFN-LASA laboratory (Milano, Italy) is involved in the High-Luminosity LHC program for the design, construction, and test of 54 superconducting high-order corrector magnets. One of the challenging project stages was the transition from the construction of prototype magnets to the series production, awarded to industries with the demanding requirement of maintaining high-quality production...
Quench protection is one of the key issues for superconducting magnets with high energy storage, especially for those wound with superconducting cables, which have low thermal conductivity between each turns. Thermal quench-back induced by a co-wound heater wire is an available quench protection scheme for the magnets wound with 6+1 type cables (6 superconducting wires wound with 1 heater...
This paper presents the results about analysis and experiment on the electrical and thermal characteristics of metal insulation (MI) REBCO racetrack coil wound with stainless steel (SS) tape under rotating magnetic field. The field windings of synchronous rotating machine can be occasionally operated under time-varying magnetic field due to the unsynchronized armature windings during...
The ITER Central Solenoid (CS) will be realized by assembling a stack of six modules. Each module is a solenoid consisting of 40 pancakes wound with a Nb3Sn Cable in Conduit Conductor (CICC). The tests of the second module (CSM#2) are ongoing at the General Atomics (GA) facility in San Diego (US). During the test campaign, the CS Module is submitted to dumps of the transport current from...
A prototype racetrack high temperature superconducting (HTS) magnet used for high-speed superconducting maglev has been in progress at Institute of Electrical Engineering, Chinese Academy of Sciences. The dynamic thermal and mechanical characteristics of the racetrack HTS coil is affected by multiple factors while it is accelerating, which has an effect on the operating margin inversely. To...
During 2020, the SULTAN test facility was upgraded to host Quench Experiments on HTS conductors. In the frame of the EUROfusion program, few cables based on the Swiss Plasma Center (SPC) Twisted Stack-Tapes design have been manufactured and successfully tested. Each conductor addresses a specific design parameter. For the first time, it was possible to observe the quench evolution and...
REBCO coated conductors are expected to apply high field superconducting magnets since they have high critical currents and excellent mechanical properties. It is well known that REBCO coated conductors have angular dependence and strain dependence of the critical current in magnetic field. However, there are few experimental results of angular dependence of critical current under strains....
Authors: Keyang Wang, V A Anvar, Yuanwen Gao, Danko van der Laan, Jeremy Weiss, Arend Nijhuis
The Conductor on Round Core (CORC®) cable or wire comprises several layers of helically wound HTS tapes on a round core with the winding direction reversed in each successive layer. This configuration can significantly reduce the AC loss while improving the bending flexibility. However, compared...
A floating offshore wind power generation has been investigated to reduce the greenhouse gas emissions in Japan. When the floating offshore wind farm transmits AC electric power to the commercial power system on the land using a copper cable, it is necessary to increase the voltage by an offshore transformer facility in order to reduce the transmission loss of the copper cable. However, it is...
INTRODUCTION
Recently, magnetic levitation techniques have been developed for various fields such as magnetically levitated vehicles and energy storage flywheels. Thus, there are many reports about levitation techniques using high critical temperature (Tc) superconducting magnetic bearings (SMBs) composed of superconducting (SC) bulk and permanent magnet (PM). However, there are not so...
High-temperature superconductors have significant potential for application in systems based on magnetic levitation: levitation bearings, magnetically suspended transport, flywheel energy storage devices, motors and generators. Bulk REBCO (where RE stands for rare earth elements) is currently a widely used material. However, the widespread use of coated conductors tapes (CC-tapes) allows to...
Use of 2G HTS superconductors in magnet applications allows creating compact magnets with large magnetic fields due to many times higher current density of superconductors in comparison with traditional metal wires. At the same time, 2G HTS tapes make the design of magnet special and require choosing 2G HTS tape parameters suitable to each magnet design. The unique properties of 2G HTS tapes...
A lightweight superconducting gantry with large momentum acceptance is under development at Huazhong University of Science and Technology (HUST), which is based on strong focusing and local achromatic technology. The essential component of this superconducting gantry is the curved alternating gradient canted-cosine-theta (AG-CCT) magnet. This paper introduces the study on coil error analysis...
A combined method was used for mapping the fields in the pulsed bending magnets of the Booster-Nuclotron transfer line of the NICA complex. In the measurements, an array of “point” search coils was used together with Hall sensors. Signals from coils were processed by digital integrators, and a specially designed fast precision ADC was used in Hall measurements. The paper presents the results...
In many industrial applications, there has been a growing need for electrical motors having high performance such as high power density and high efficiency. An electrical motor with high temperature superconducting (HTS) coils allows to offer those advantages due to the very high current density compared with conventional superconducting motors. HTS motors can be divided into an inner rotor...
Permanent magnet guideway (PMG) has commonly been used for an HTS maglev system so far. In some previous studies, electromagnetic guideway (EMG) was proved to have some advantages in a practical HTS maglev construction.
EMGs with different geometries produce different magnetic field distributions and have different performance characteristics in a HTS maglev system. In this study, comparative...
The concept of an electric aircraft and ship implies the development of an entirely new electric propulsion system. Among the key technologies of these systems, electric motors and generators are required for high performances such as high efficiency and high specific power. In this paper, a study on the electromagnetic design of the MW class superconducting (SC) machine according to...
A conceptual design study of superconducting toroidal field (TF) magnet for a steady-state Korean fusion demonstration reactor (K-DEMO) was done in 2015. Through some minor design modifications of the K-DEMO TF magnet, the maximum toroidal field strength of the K-DEMO is expected to be about 16 T. In order to test a Cable-In-Conduit Conductor (CICC) of the K-DEMO TF magnet, a conductor test...
Sirius is a 4th generation light source with a sub-nm.rad horizontal emittance currently under commissioning in Brazil. The Sirius beamlines will mainly use insertion devices as the source of synchrotron light, and some of the beamlines will use the currently installed central dipole magnets (permanent magnets) of 3.2 T. However, there is a demand for a high-energy x-ray tomography beamline...
Abstract: A closed-loop high temperature superconducting (HTS) magnet with thermal switch, wound by REBCO wire, is proposed, which can be magnetized by flux pump and operated in persistent current mode. In this paper, the structure, fabrication and principle of the magnet is explained. Because the magnet has the structure of thermal switch, it can be excited to saturation efficiently....
The new HEL (Hollow Electron Lens) units are part of the upgrade baseline of the High-Luminosity LHC accelerator (HL-LHC) will be installed in the machine ring at point P4 on each counter-rotating LHC proton beamline during a long shutdown in 2025-2027 at CERN. The main goal is to achieve active control of the proton beam halo as a robust solution of risk mitigation to improve the collimation...
The high-temperature superconductor REBa2Cu3Oy (REBCO) is expected to be applied to fusion magnets because of its high critical current density at 20 K [1]. Various kinds of REBCO conductors with a large current capacity have been developed for the fusion magnets by stacking the REBCO tapes such as FAIR conductor [1]. A drawback of REBCO conductors is that the buffer layer prevents current...
Racetrack model coils (RMC) have been built at CERN during the past decade, as a R&D tool to qualify conductors and technologies developed for high field superconducting magnets. Racetrack model coils, assembled in a dipole magnet configuration, proved to be an efficient instrument reducing cost and feed-back time while developing new magnets. In a similar way as for the HL-LHC project, CERN...
With 3 GeV electron beam energy for the National Synchrotron Light Source II (NSLS-II) ring, only superconducting wiggler (SCW) producing greater than 4T peak field can cover photon energy range of 20keV and 200keV with sufficient number of photons. The High energy Engineering X-ray (HEX) Diffraction beamline, which is primarily funded by the New York State Energy Research and Development...
The muon g-2/EDM experiment, which aims at the ultra-precise measurement of muon anomalous magnetic moment (g-2) and electric dipole moment (EDM), is now under planning at J-PARC. For muon g-2, there is a discrepancy of more than 3-σ between the theoretical calculation in the Standard Model and the experimental results in the preceding experiment. Therefore, muon g-2 is one of the promising...
Two out of six Poloidal Field Coils (PFC) are already delivered to the ITER Organization. The PFC are built winding, impregnating and vertically stacking double pancakes (DPs) of NbTi Cable-in-Conduit conductors into a Winding Pack (WP). Later, the Winding Pack (WP) is impregnated for ground insulation and clamping devices are installed for structural support and interface with the rest of the...
In April 2021, four Toroidal Field Coil (TFC) built by European industries are already delivered to the ITER Organization. The TFC are composed mainly by a superconducting Winding Pack (WP), and the enclosing Coil Cases (TFCC).
One of the main parameters characterizing the TFCs is the Current Centre Line, defined as the barycentre of the WP conductors. The CCL has been initially calculated...
With the increase of the permeability of renewable energy, the equivalent inertia and damping of the power system gradually decrease, which makes the power system stability problem more and more prominent. By emulating the electromechanical transient characteristics of synchronous generators, the virtual synchronous generator (VSG) technology enables the renewable power generator to have the...
Research and development of large-current High-Temperature Superconducting (HTS) conductors toward the application to magnets of experimental nuclear fusion devices are in progress at NIFS. As a candidate, the FAIR conductor [1] has been developed. Using a number of HTS REBCO tapes, we have been optimizing the manufacturing process of the conductor by repeating current-transport tests in...
If filaments in a multifilament coated conductor are insulated electrically one another, the current carried by each filament could be restricted by its lowest local critical current along its length. The critical current of such a multifilament coated conductor could be the sum of the lowest local critical currents of all filaments. Considering a longitudinal variation in local critical...
REBCO with its high-strength substrate is the preferred superconductor for high-field applications and is the choice for the NHMFL’s 40 T all-superconducting magnet. Many electromechanical characterizations of this conductor have been performed in its longitudinal direction which is its primary load path. Little has been reported on structural limits in its transverse, narrow edge, direction...
In recent year, there has been remarkable progress in the use of high-field rare-earth barium copper oxide (REBCO) coils in NMR, MRI, and accelerator applications. No-insulation (NI) winding techniques are adopted to achieve high thermal stability and high current density. Thus, each winding in a non-impregnated NI REBCO coil can deform separately and move freely because of the thermal strain...
No-insulation (NI) high-Tc superconducting (HTS) coils process much higher thermal and electrical stability than the conventional insulated coils. In some rotating machines and Maglev trains, HTS coils carry persistent current and serve as the permanent magnets. For these applications, the main issue is that the demagnetization of HTS coils caused by the local external alternating fields. This...
Recently, as interest in high-efficiency motors has increased, motors of various structures have been developed. In particular, the axial flux motor has a relatively low leakage flux, so the power density, output torque, and efficiency are high. High-temperature superconducting (HTS) coils have a higher magnetic flux density than permanent magnets. Therefore, by applying HTS coil to the...
In this paper, a laboratory electromagnet utilizing high temperature superconducting (HTS) coils is designed and analyzed. The laboratory electromagnet is applied to excitate high magnetic fields compared with the conventional laboratory electromagnet with copper coils. The proposed electromagnet was composed of iron-core, HTS coils, and cryostat for the HTS coils. The components are designed...
A proton therapy equipment named SC200 is developing in the Institute of Plasma Physics Chinese Academy of Sciences (IPP, CAS) and Heifei CAS Ion Medical and Technical Devices company. In order to develop a light weight gantry for proton therapy, the Canted Cosine theta (CCT) superconducting magnet technology was considered to apply in the superconducting gantry development. The designs of two...
CERN is currently investigating the feasibility of a future collider - the Future Circular Collider (FCC)- as a potential successor of the Large Hardon Collider (LHC), providing scientists in the field of high energy physics with a powerful discovery tool. A 100 km tunnel hosting a circular electron–positron collider as a first stage towards a 100 TeV proton–proton collider would probe new...
In the magnetic Czochralski crystal growth (MCZ) process, a Lorentz force that influences the flow and tends to reduce the amplitude of the melt fluctuations by applying a magnetic field outside the furnace body. It is a main method to suppress the uneven distribution of impurities and reduce the density of crystal defects. The strong magnetic field provided by superconducting magnet is a...
A lightweight superconducting (SC) gantry with large momentum acceptance is under development at Huazhong University of Science and Technology (HUST). Three types of combined-function quadrupole-sextupole (QS) magnets are used to suppress the chromatic dispersion for the large momentum acceptance. Moreover, the size and weight of the gantry can be further reduced. This paper introduces the...
To study the properties of the Higgs, scientists from the Institute of High Energy Physics have proposed to build the Circle Electron Positron Collider (CEPC) and published a conceptual design report in 2018. In order to improve the luminosity of the CEPC, the final focus system in the interaction region is continuously upgraded. According to the latest physical requirements of superconducting...
The wireless power transfer (WPT) using magnetic resonance coupling method has been known to have the advantage of being able to transfer power across large air gap with considerably high efficiency. As well as, as such a method can eliminate the physical contact loss in the system, it provides an ideal solution for the problem of contact losses in the power applications. From these reasons,...
Since the late 2000s, research on electric turbo engine propulsion aircraft is being actively conducted in the aircraft industry to reduce environmental pollution and increase energy use efficiency. The electric propulsion aircraft will be equipped with a large-capacity, high-power density electric motor and generator with superconducting technology. In order to develop superconducting...
The composite method is an effective way to obtain superconductors with better performance. Through the combination of the first and second generation high temperature superconductors, the stability of superconductors can be improved, the engineering current density can be increased, and the AC loss of superconductors can be reduced. In this paper, a HTS transformer with first and second...
Proton therapy (PT) is a precise and efficient radiotherapy method in modern medical treatment, which can be focused on the lesion location to kill the tumor cells with little affection on the normal tissues and thus largely reduce the potential side effects. However, the proton therapy instrument is usually very huge with a large occupation in the space. In order to reduce the instrument...
Rotating coil magnetic field measurement system is an essential component to achieve the multipole harmonic fields measurement in accelerator quadruple magnets. The fundamental requirement for the coils are accuracy, easy fabrication and low-cost, so that the coil parameters can be customized to the magnet requiring test. This paper introduces the application of PCB technique on rotating...
Abstract—Superconducting magnetic energy storage system (SMES) has the advantages of fast response, four quadrant adjustable active and reactive power. It can improve the stability of power system, improve power quality, be used as distributed power system and energy management in power system. The research and development of large capacity energy storage magnet is an important...
The High Luminosity LHC requires dipole orbit correctors grouped in double aperture magnet assemblies. They provide a field of 3.1 T at 100 A in an aperture of 70 mm. The current standard design is a classical cosine-theta layout made with ribbon cable. However, the electric insulation of the ribbon cable is however not radiation-resistant enough to withstand the radiation load expected in the...
Design of a beam transport line for a newly developed three-dimensional spiral injection scheme is discussed. This transport line is unique and one of key equipment for a new experiment at J-PARC, which measures a muon anomalous magnetic moment (g-2) and electric dipole moment (EDM) to explore a new physics beyond the standard model. Very precise measurement on spin precession angular momentum...
We present the design of a four-layer, Canted Cosine Theta (CCT) Nb3Sn dipole magnet as part of the general R&D program for high field superconducting magnets supported by the US Magnet Development Program (US-MDP). Future testing with HTS inserts in a hybrid configuration motivates the design’s large clear aperture of 120 mm and target operating dipole field of 12 T. First, we show results...
Abstract:
High-temperature superconducting (HTS) magnet is a promising candidate for transportation systems and power systems, such as ultra-high field magnet, electrodynamic suspension (EDS) train, magnetic resonance imaging (MRI), due to its large current-carrying capacity and low power loss. The critical current of the HTS magnet depending on magnetic flux density is an essential...
We propose the electric propulsion system which are composed of 10 MW superconducting generators, superconducting transformers, superconducting cables, and 2 MW superconducting motors. The design study of 2 MW fully superconducting motors with a rated voltage of 1 kV is being conducted. On the other hand, the 10 MW fully superconducting synchronous generators were designed so as to operate at...
Accelerator magnet test facilities frequently need to measure different magnets on differently equipped test stands and with different instrumentation. Designing a modular and highly reusable system that combines flexibility built-in at the architectural level as well as on the component level addresses this need. Specification of the backbone of the system- the interfaces and dataflow for...
Protecting a high temperature superconducting (HTS) magnet from a quench event is a challenging task, especially in the case of accelerator magnets where current density is usually very high. Because of the slow normal zone propagation velocity, the long reliable quench detection method by coil voltage may not be timely for HTS anymore, leaving HTS magnets under danger of overheating. Many new...
In order to meet the requirements of the large HTS solenoid detector magnet for Circular Electron Positron Collider (CEPC), a new high temperature superconducting cable, Aluminum stabilized Stack ReBCO Tape Cable (ASTC) has been proposed and developed. The HTS conductor is one of the promising options for the large solenoid applications. In this study, a 20 layers ASTC sample has been...
AC loss is a major heat load in the fast-pulsed, superconducting ITER coils, and thus a design driver for the cryo-system and superconductor. Given the importance of AC loss, extensive AC loss characterization of the components of the ITER coils, from the superconducting strands, cables and insert-coils to the completed coils, were conducted over the past years.
Following factory cold...
Space charge compensation technology using multiple multipolar magnetic field components has been applied to high intensity beam transport. In order to realize this compensation technology in a limited space, we devised a compact size permanent hybrid multi-pole magnet. This magnet can produce two or more adjustable multi-pole components at the same location. In this presentation, we will...
We proposed the novel separation method, which is the combination of magnetic separation and selection tube, aiming at more precise and easier separation for the paramagnetic substances than the conventional High Gradient Magnetic Separation (HGMS). In order to control and separate the paramagnetic substances with magnetic force, the magnetic field of higher than 5T and high gradient magnetic...
High–temperature superconductors (HTSs) still hold some unignorable issues, such as AC losses and its poor robustness against normal transition. For HTS tapes, dividing superconducting layer into filaments by striation shows remarkable effects on reducing AC losses. However, it could deteriorate robustness due to blocking a current sharing among filaments. Thus, plating copper on the entire...
The J-PARC muon g-2/EDM experiment aims to perform ultra-precise measurements of anomalous magnetic moments (g-2) and electric dipole moments (EDM) from the spin precession of muons in a precise magnetic field, and to explore new physics beyond the Standard Model. On experimental requirements, the beam must be stored in a compact storage orbit with a diameter of 66 cm, which is about 1/20th...
Ceramic powders A1-xSrxTiO3 (where x = 0.02, and A=Ba2+, Pr3+, Sm3+, Eu3+, and Er3+) were synthesized by solid-state reaction method and sintered at up to 1400 °C. The phase formation, elemental composition, and microstructure of the sintered samples were investigated by TGA, XRD, EDX and SEM techniques, respectively. The results of the partial substitution of Ba ions by other rare earth ions...
The high-field magnets experience the large amount of mechanical stress as a result of Lorentz forces. During the magnetization of the coil, strong Lorentz forces give rise to hoop stress, which can cause mechanical failure, resulting in the degradation of the coil performance. A recent study led to the discovery that scratching the GdBCO-coated conductor (CC) tapes ameliorated the degradation...
We aim to develop a persistent-mode 1.3 GHz (30.5 T) LTS/HTS NMR magnet. For protecting the layer-wound REBCO innermost coil from quench, we have proposed the intra-Layer No-Insulation (LNI) method. This winding technique employs single-sided insulated copper sheets as inter-layer materials to provide the no-insulation state within each layer. For quench protection, the most influential...
REBCO tapes have good critical current characteristics under high magnetic fields. Their application to superconducting magnets generating above 25 T is under active study. However, performance inhomogeneity along their length can cause damaging hotspots. Adapted winding technologies are needed to mitigate this phenomenon. One of such winding techniques is the two-tape bundle co-winding...
A Cos-theta type fast cycling dipole model for synchrotron is being developed at IMP. The magnetic field of the dipole is 6 T with maximum ramp rate is 1 T/s. The coil inner diameter is 80 mm and two-layer coils are used to produce accelerator field quality in two third of coil aperture. Rutherford cable with 316L stainless steel core is used to reduce the inter-strand couple loss. Low loss...
A project to develop a compact heavy-ion therapy device has been initiated at the National Institutes for Quantum and Radiological Science and Technology. The therapy device uses a 430-MeV/u synchrotron with superconducting bending magnets as a main accelerator. In order to reach the required output of the heavy-ion beam, the bending magnets have been designed to be operated alternately from...
In heavy particle radiotherapy, a rotating gantry enables charged particles to be delivered to a tumor with great accuracy. Therefore, cancer therapy that minimizes unnecessary damage to a patient can be realized by using the rotating gantry. The world’s first rotating gantry composed of superconducting magnets was developed in Japan. Using superconducting magnets instead of conventional...
We have been developing a no-insulation (NI) REBCO coil system for medical accelerators and high-field magnetic resonance imaging (MRI). There are increasing attempts to apply NI winding technology to achieve both high current density and high thermal stabilization of REBCO coils. However, REBCO coated conductor has a tape shape, and when a magnetic field is applied vertically to the tape...
REBCO coated conductors have a high critical current density in a high magnetic field at low temperature. Therefore, the research and development of REBCO coated conductors have proceeded for high magnetic field applications. A critical current of REBCO coated conductor shows field angular dependence and strain dependence. Especially, the mechanism of the strain effect for REBCO coated...
Applications for coated conductors, such as fusion magnets, power transmission and generator windings, require high current-carrying capacity. This requirement can be fulfilled by various cable concepts using commercial lengths of REBCO coated conductors with high current-carrying properties, such as Rutherford cables. In the past few years, our group has successfully developed Quasi-isotropic...
Superconducting magnetic energy storage (SMES) has the advantages of high efficiency, longevity, and excellent instantaneous response with high power. However, it has the disadvantage that its storage density is extremely small compared to other power storage devices. The no-insulation coil (hereinafter referred to as "NI coil") is expected to be a winding method that can achieve both high...
The ITER Central Solenoid (CS) consists of a stack of six independent coil packs called modules. It features a total height of 18 m and a diameter of over 4 m. The modules are in an advanced stage of fabrication by the US ITER Project Office (USIPO) and its subcontractor General Atomics (GA). A qualification module mock-up at one to one scale but of reduced height was wound and Vacuum Pressure...
The authors’ group is investigating a quench protection method for HTS coils that use Cu tape co-wound with HTS tape. In this method, the voltage $V_s$ across the resistive zone in the HTS coil is monitored by measuring the voltage difference between the HTS coil and the co-wound Cu tape coil in normal operation. When $V_s$ exceeds the quench detection voltage, the HTS coil is disconnected...
The no-insulation (NI) winding technique provides high stability of HTS pancake coils and a high magnetic field NI HTS magnet was developed. On the other hand, the balance between the turn-to-turn contact resistance and the coil inductance is an important factor to characterize the thermal stability and charging delay of NI HTS coils. So, it is very important to accurately measure and evaluate...
Large-scale high temperature superconducting (HTS) wind power generators suffer from the high electromagnetic force and high torque due to their high current density and low rotational speed. Therefore, to maintain the mechanical strength of the HTS coil, the torque and Lorentz force of the HTS wind power generator must be carefully investigated. This paper deals with the experimental test...
High Temperature Superconductor (HTS) based magnets are potential candidate for the future fusion reactors and electrical industries due to its compact size and operational economy. A SS laminated BSCCO-2223 HTS tape based and double pancake wound compact solenoid coil with an inter-double pancake joint of bore diameter 50 mm with 24 nos. of turns has been fabricated and tested at LN2...
A new solution for cost effective, high average power (2 GeV, 6 MW) proton accelerator has been proposed and studied since 2013. The energy limit of isochronous accelerator has been successfully increased from 1GeV to 2GeV. In 2019, China Institute of Atomic Energy (CIAE) started the design of a 2 GeV FFAG accelerator and launched the preliminary study on the design of a high-temperature...
Three racetrack type double-pancake coils were wound and assembled in a certain sequence to form a module. To improve the anisotropism between the straight sections and circular sections, the bobbin was designed and some clamping fixtures were added on both sides and on the straight sections. By investigating the viscosity and torque of rotor, the optimum range of temperature for impregnating...
Fusion for Energy (F4E), the European Domestic Agency for the International Thermonuclear Experimental Reactor (ITER), is responsible for the supply of 5 out of the 6 Poloidal Field (PF) Coils: PF2-PF6. While the 9 meter diameter PF6 was manufactured by the Institute of Plasma Physics Chinese Academy of Sciences (ASIPP) and tested in the cold test facility at Cadarache under a collaboration...
Feasibility study of ITER In-vessel coils bracket manufacture and integration had been developed in Institute of Plasma Physics, Chinese Academy of Sciences. The ITER In-Vessel Coil system is comprised of Edge-Localized Mode (ELM) and Vertical Stabilization (VS) coils. The ELM coils are used to mitigate the Edge Localized Modes and the VS coils are used to provide Vertical Stabilization of the...
Canted-Cosine-theta (CCT) magnet is an excellent dipole magnet structure design for developing high-field accelerator magnets, because of its modular construction and the prevention of the Lorentz-force-induced conductor stress accumulations. Although REBCO tapes can maintain a relatively higher engineering current density than other superconducting conductors in the high field environment, it...
The U.S. High-Luminosity LHC Accelerator Upgrade Project (HL-LHC AUP) is developing MQXFA magnets, a series of 4.5 m long 150 mm aperture high-field Nb$_3$Sn quadrupole magnet for the Hi-Luminosity LHC upgrade at CERN. Five Pre-Series magnets, MQXFA03 through MQXFA07, have been developed. During the magnet assembly stage, we perform magnetic measurements of the coil packs and magnets to track...
Two types of nested orbit combined correctors are necessary for LHC upgrade, so called MCBXFA and MCBXFB. They shared the same cross section, but feature different lengths, 2.5 and 1.5 m, respectively. The power tests performed on two prototypes showed an excellent performance when individually powered, but the training to reach nominal torque in combined operation was very long. Moreover,...
AC losses in stacked bundle conductors exposed to external magnetic fields are numerically evaluated by means of a two-dimensional finite element method formulated using a self-magnetic field due to currents induced in an analysis region. The bundle conductor is composed of two pieces of rare-earth-based coated conductors without electrical insulation to improve the thermal stability. In the...
Bi:2212 superconducting cables are being considered for use in high field magnets such as those in the next generation of particle accelerators. However, a comprehensive understanding of their behavior is necessary before full-scale magnets can be constructed. The magnetization and flux creep in the superconductor can lead to significant field errors which need to be compensated. To study...
For mechanical reinforcement against the huge Lorentz forces in high magnetic fields, epoxy resins are commonly used to impregnate the high temperature superconducting (HTS) coils. However, performance degradation of the epoxy impregnated HTS coils is inevitable due to different thermal expansion coefficients between the epoxy resin and the HTS tape. The ice impregnation technique of pulsed...
The flux pump technology is bale to output ultra high current for the High temperature superconducting (HTS) magnets without the copper current leads. This can make the HTS magnets system more compact and save more energy. Currently, the flux pump technology is moving forwards to high current level up to 1-2 kA. But there are still mane components to be optimized and studied, and the HTS...
This paper studies the principle of direct current and DC bias voltage induced by superconducting tape in a linear magnetic flux pump system. The external magnetic field is a comprehensive magnetic field composed of a bias magnetic field and a traveling wave magnetic field. An experimental platform for linear magnetic flux pumps was built. Using a combination of simulation and experiment, the...
As the experimental ITER fusion reactor faces its final construction phase, design activities of the next reactor DEMO that will supply net electrical energy to the grid are being conducted in Europe. DEMO will be significantly larger than ITER, and its magnet system will be key to confine the plasma and control its shape. In particular, the Toroidal Field (TF) Coils are necessary to generate...
Recent advances in the fabrication of high-temperature superconducting (HTS) coils allow the design of superconducting accelerator magnets working in a persistent current mode. There are many various rather low field magnets in the particle accelerators which operated in the DC current mode. At Fermilab was designed, fabricated, and tested the HTS dipole magnet model having 20 mm air gap and...
Abstract — This work investigates the effect of rotor eccentricity and current harmonics on the performance of high-speed permanent magnet (PM) generators (HSPMG) with multi-physical analysis. First, the effect of rotor eccentricity in the no-load and load conditions on the distributions of magnetic flux density and electromagnetic force in the generator is studied and the allowed...
In this article, we proposed a method of using multiple linear flux pumps to charge an HTS magnet and set up an experimental system. The system mainly includes three linear-motor flux pumps and five HTS double pancake coils, of which the five coils form an HTS magnet. Each linear-motor flux pump adopts an independent inverter and a DC power supply for cluster control. In order to obtain the...
In conventional transport systems using wheels and belts, there are friction that generates wear of mechanical parts and consequently reduces the whole system efficiency and this a problem, especially when using it in special environments such as clean room. As a way to solve this problem, a magnetic levitation system was developed using magnetic levitation as main technology. Called Hybrid...
Nb3Sn conductors are prone to quench due to deposition of heat energy from disturbances such as flux jumps and cracking of nearby epoxy, which push the conductor into the normal state. In Nb3Sn magnets, this manifests as training, wherein the magnet can reach a progressively higher current after a succession of quenches. By incorporating substances with a higher heat capacity at cryogenic...
Sigmaphi participated to QUACO PCP whose objective was to propose an innovative solution for MQYY superconducting quadrupole magnets of HL-LHC Insertion Region. QUACO project was divided in three phases: a feasibility study, a detailed study including mock-ups and the manufacturing of a MQYY first-of-a-kind based on an innovative concept.
The innovation proposed by Sigmaphi concerns the...
For high field accelerator magnets, it is more attractive to wind the coils with a compact high current-carrying capacity cable, which is composed of tens or even hundreds of superconductors. In the last decades, various ReBCO cable conceptions have been proposed, but only a few cables, such as Roebel cable, can achieve a current density as high as single tapes. However, the high performance...
LN2/CF4 mixture would be an effective coolant and insulating medium of high-temperature superconducting (HTS) magnets and power devices, which could provide a cryogenic environment in the temperature range of 50 to 100 K and serve as a liquid dielectric. In this paper, recent progress concerning the LN2/CF4-cooled HTS power devices including superconducting fault current limiter (SFCL) and...
In this study, the quench initiation and propagation characteristics of REBCO coil, which was electrically and thermally insulated by a vanadium III oxide (V2O3), were investigated under internal heater activation. When the quench occurs in REBCO coil, V2O3 insulator can enhance the thermal stability of REBCO coil due to its automatically and remarkably switched from high to low turn-to-turn...
The REBCO coil, which was electrically insulated using a metal-insulator transition (MIT) material between turn-to-turn contact layers, can achieve high stability in the transient operation as well as fast response of magnetic field in the normal operation due to its automatically switched electrical resistivity of MIT material according to the temperature changes. Among of MIT materials, A...
Currently, the development of superconducting magnetic energy storage devices (SMES) based on the cables from high-temperature superconducting tapes of the second generation are carried out. Such SMES will be used, for example, in the NIKA project to power the pulsed magnets of Booster and Nuclotron accelerators. Similar cables may be used in accelerating magnets as well. The number of working...
During the NHMFL 32 T magnet project, a program to develop a reliable method for making soldered lap joints between REBCO tape conductors was initiated. Several combinations of solder, flux and process were tried and then tested in liquid nitrogen. A standard process was adopted from the findings of that study. For each unique REBCO conductor piece procured for the 32 T project, a lap solder...
We have been studying a magnetic levitation system using a magnetic shielding effect of HTS bulks. The analysis method is numerical simulation utilizing the 2D and 3D finite element method software, COMSOL Multiphysics. This system consists of three items which are an iron rail, the HTS bulks, and the magnet. In the former work using a permanent magnet, the peak levitation force was smaller...
As is well known all types of superconductors are affected by AC losses.
Those losses occur when a time varying current flows in a superconductor or when it’s subjected to a variable magnetic field.
The main effect of these losses on the conductor is temperature rise due to the energy dissipation within the superconductor. Many methods were previously studied in order to reduce the magnitude...
The last bending section of a proton therapy beam line is mounted on a rotating gantry to target the cancerous cells of the patients from all possible angles. Such capability can increase the effectiveness of cancer treatment as the tumors would receive the appropriate amount of radiation dose with a minimum impact on the surrounding healthy tissue. Superconducting magnets with their high...
LQXFA/B production series cryogenic assemblies are being built for the LHC upgrade by the HL-LHC Accelerator Upgrade Project (AUP). These contain a pair of MQXFA quadrupole magnets combined as a cold mass installed within a vacuum vessel, and are to be installed in the IR regions of the LHC. The LQXFA/B are being tested at 1.9 K to assess alignment and magnetic performance at Fermilab’s...
A beam separation dipole of the High-Luminosity LHC, known as MBXF, is a 7-m NbTi magnet, which is designed to generate 35 Tm at the operating condition of 1.9 K. The magnet has a collared yoke structure with a 150-mm-aperture single-layer coil. The dipole field is 5.6 T at nominal operating current while a b3 integral is required to be within 2.9 units. The target pre-load is set to 115 MPa...
The Large Hadron Collider (LHC) upgrade, called High Luminosity LHC (HL-LHC) is planned for the next decade. A set of twin aperture beam orbit correctors positioned on the approaches to the ATLAS & CMS experiments will be developed. Tow institutes IHEP (Institute of High Energy Physics), IMP (Institute of Modern Physics), and one company in China will work on the magnet R&D and series...
High temperature superconductor (HTS) coil has superior current-carrying ability, and can trap higher magnetic fields, thus shows a promising application on machines with super high power density. Winding coils with bare tapes without any insulation, which is called no-insulation (NI) coil, can significantly enhance the thermal stability and reliability of HTS coils. However, in many...
The paper presents a description of the magnets for transfer line to transport ions from the Booster to the Nuclotron at the NICA project.
The transfer line has a complex three-dimensional structure because of the Booster and the Nuclotron are located in two levels. To realize complicated geometry of the transfer line necessary to reduce the magnets weight. Due to this they are made pulsed....
The ITER PF system consists of 6 ring coils and it provides magnetic field for plasma shaping and position control together with the Central Solenoid (CS) coils. It needs to operate in a fast pulse mode, leading to induced voltages of up to 14 kV on the coil terminals during operation. The cable-in-conduit conductors (CICC) with Niobium-Titanium (NbTi) superconducting material are used in the...
High Temperature Superconductor (HTS) are one of the most promising applications of HTSs as they offer a means of charging magnetic loads without the need for physical current leads. Flux pumps have been generally built using Low Temperature Superconductors (LTSs), although their implementation using HTSs has been the subject of recent research interest owing to their lower cryogenic...
In order to examine the applicability of superconducting technology to fields of industrial applications such as linear conveyor, transfer, and transport systems, we investigated AC loss characteristics of HTS sample coils under conditions assumed for use in power electronics devices. Since inverters are used in the drive circuit of power electronics devices in a linear transfer system and so...
In the case of a REBCO superconducting coil, the coated conductors endure both tensile and bending strain. Therefore, the mechanical behavior of REBCO coated conductors and its effect on the critical current under combined tensile-bending deformation should be revealed. In this study a mixed-dimensional laminated composite finite element model (FEM) for REBCO conductor is developed for stress...
In the quest of higher field accelerator superconducting magnets, essential parts of their design are the so called yokes, which are traditionally made of low – carbon magnetic steel. In currently used magnets, they are typically found in the form of fine – blanked laminations, or machined from laminated heavy plates. The material’s choice is made based on a compromise between the high...
The future of the particle accelerators points to a new CERN’s circular collider with an order of magnitude increase in the center-of-mass energy compared to the Large Hadron Collider (LHC). To achieve this increase from 14 TeV to 100 TeV a 100 km tunnel will be required to host the collider. This particle accelerators requires a new generation of double aperture superconducting magnets,...
To guarantee the required performances stringent dimensional requirements have been defined for the ITER TF coils.
The assembly of the European magnets from its components, the Winding Pack (WP) and the stainless steel Coil Cases (CC), is currently under responsibility of SIMIC SpA in the framework of a Fusion For Energy contract.
The process has been divided in the following stages:...
The superconducting electrical machines are going to be widely used in many modern transport applications in near future. In fact, their great features such as high efficiency, high torque density, high power density, and lighter weight make them an excellent fit for electric aircraft and marine applications. The fully superconducting machines built with superconducting magnets requires a...
REBCO wires have high thermal stability and high current density, therefore, it is expected to be applied to high magnetic field magnet for NMR, MRI, and accelerators. On the other hand, there is the problem such as mechanically deteriorations and damages of REBCO coils. Because REBCO wires are tape shape, when charging and discharging, screening currents are induced to circulate in the...
Targeted alpha-particle therapy is a cancer treatment method using alpha-emitting radioisotope (RI), and is expected as a treatment method for progressive cancer. We are conducting research toward the development of a High-temperature-superconducting Skeleton Cyclotron (HTS-SC), which is an ultra-compact and high-intensity accelerator capable of stably producing the alpha-emitting...
Due to the normal zone propagation velocity (NZPV) of a high temperature superconductor (HTS) being about 100-1000 times slower than that of a low-temperature superconductor (LTS), the quench detection is a difficult challenge for HTS structures so far. To propose more effective quench detecting methods and criterion, it is necessary to reveal the mechanism and multi-field coupling behavior...
High-temperature superconducting (HTS) magnets have been widely used in the fields of electricity, transportation, medicine, and scientific experiment. However, HTS magnets generally suffer from the thermal stress and electromagnetic stress during manufacture and operation, deteriorating its mechanical properties as well as restricting its further development. This study is aimed at improving...
Stress managed magnet designs are being developed to limit the strain and stresses applied to the conductor during powering. The canted cos $\theta$ (CCT) design is one of the proposed solutions. In this design, the conductor is wound around a mandrel: the impregnation process creates a bonding between the two, that can fail when the magnet is powered. The energy releases consequent to the...
2G high temperature superconducting (HTS) coil working in persistent current mode (PCM) has shown a superior potential in linear motor applications. While due to the external magnetic field, specifically, the harmonic field component generated by the ground coils, the HTS coil used in synchronous motor suffers inevitable current decay resulting from dynamic resistance, which is usually much...
With the merits of passive stability, energy-saved and environment-friendly, high-temperature superconductor (HTS) magnetic levitation (Maglev) is regarded as a promising candidate for the future high-speed transit. Amont the two main HTS maglev methods the bulk-type and stack-type, the stack-type HTS maglev is of the merits of larger engineering current density, larger loading potential and...
As one of the key components of synchrotron injection and extraction system, the septum magnet not only needs to produce a strong magnetic field to deflect the injection/ extraction beam, but also cannot affect the circulating beam passing by it. Otherwise, the disturbance of the leakage magnetic field to the circulating beam will affect the beam loss. Based on the theory of electromagnetic...
Our research has shown that an energy conversion/storage device composed of a permanent magnet and a superconductor coil has superior performance. In order to improve the conversion efficiency and energy storage capacity of this device. An effective method to enhance the interaction behavior between a permanent magnet and a closed superconductor coil is proposed in this paper. The functions...
Field shaper is a powerful supplement for the magnetic field generator (namely, the driving coil) in electromagnetic forming (a high velocity manufacturing technology), which utilizes the magnetic shielding effect of deticated-shaped electrical-conductor to alter the path of the pulsed magnetic field, so as to obtain the desired spatial distribution for the magnetic field as well as the pulsed...
A prototype bipolar correction magnet with permanent magnets, which is realized by rotatable permanent magnet rods, was fabricated and magnetic field measurements were performed. Based on the evaluation, improvement on the magnet structure is under study. The new design will be discussed here.
We explore methods for stabilization and control of persistent currents in high-temperature superconducting Bi-2223 coils. Several different techniques are considered, including flux transfer through inductive coupling as well as other novel approaches. These different methods are tested at 77 K using an experimental setup with a closed loop of Bi-2223 conductor powering two iron-dominated...
This paper deals with the fabrication and preliminary rotational test of an high-temperature superconducting (HTS) synchronous motor with linear-motor type flux pump exciters. This HTS synchronous motor is composed of copper armature windings, HTS field windings, linear-motor type flux pump exciters, vacuum chamber, cryogenic cooling system, etc.The various core components were manufactured,...
High-field magnets are often demanded for advanced scientific studies. Although a hybrid coil design comprising Nb-Ti, Nb3Sn, and HTS (High Temperature Superconductors) are potential candidates for such application, the costs of Nb3Sn and HTS are expensive compared with Nb-Ti. Permanent magnet can join hybrid magnets. By generating additional field about 1 T by permanent magnets, required...
For future larger and higher energy particle accelerator, the Fourth superconducting electron cyclotron resonance ion source (FECR) is building in Institute of Modern Physics, Chinese Academy of Science. In order to verify the technology of the Nb¬3Sn superconducting magnet for FECR, a prototype which consists of two axis solenoid coils and six sextupole coils with cold iron yoke has been...
The 9.4-T whole-body MRI superconducting magnet system with a warm bore of 800mm in diameter has been designed and fabricated in the Institute of Electrical Engineering, Chinese Academy of Sciences (IEE, CAS) for bioscience research applications. A passive quench protection system with the coil subdivisions and the heater network to accelerate quench propagation has been employed to avoid the...
VIPER cable is a high-current and high-field capable high temperature superconducting (HTS) cable designed by MIT and Commonwealth Fusion Systems (CFS) for large scale superconducting magnet system applications. The VIPER cable design is based on the high-temperature superconductor cable architecture known as Twisted Stacked Tape Conductor (TSTC) first proposed by Takayasu et al. [1]. Several...
In the framework of a joint collaboration funded by US Department of Energy (DOE), a large bore “Cable Test Facility Magnet” is under development. This is a joint effort between the Office of High Energy Physics (HEP) and the Office of Fusion Energy Sciences (FES). A 15 T Nb3Sn dipole magnet is being developed at Lawrence Berkley National Laboratory (LBNL). The magnet will produce the...
We have been developing the Frequency Loss Induced Quench (FLIQ) protection system for high-temperature superconducting magnets. We have studied the sensitivities of the various FLIQ system parameters to understand the design of an effective quench protection system. FLIQ drives AC current in the magnet coil and generates AC losses. The heating associated with the losses quenches the HTS...
Permanent magnets are necessary materials for particle accelerator components. As the beam intensity of the accelerator increases, demagnetization effects in permanent magnet materials is becoming one of the important issues. In order to measure the demagnetization rate of the magnet materials such as NdFeB, SmCo, and Ferrite magnets, a neutron irradiation experiment in Kyoto University...
Abstract: The segmented core reactor is small in size and low in cost. It not only has good electromagnetic compatibility, but also has a larger inductance value due to the multi-section air gap structure. However, under the interaction of electromagnetic force and magnetostriction at the air gap, the reactor core is deformed, causing vibration and generating louder noise than other ordinary...
We report on power test of a rapid-cycling superconducting accelerator magnet. The dual-bore magnetic core of 0.5 m length and two 10 mm (vertical x 100 mm (horizontal) beam gaps arranged in vertical plane is energized with HTS-based power cable. The 3-turn magnet cable is placed within magnetic core space where core descending magnetic field is strongly suppressed minimizing ramping B-field...
Magneto plasma sail is a space propulsion system with a higher fuel efficiency for future deep space explorations. The thrust to power ratio of the magneto plasma sail can be greatly improved with a superconducting magnet by generating a larger magnetic field with less power consumption. The thrust of the magneto plasma sail is produced by the transfer of momentum from a solar wind plasma to a...
- Introduction
Iron oxide scale removal from boiler feed water was studied to suppress the deterioration of power generation efficiency of the thermal power plants adopting oxygenated treatment (OT), by using high gradient magnetic separation (HGMS). Since the magnetic susceptibility and secondary particle size of the target particles have large effects on the magnetic separation efficiency,...
Removal of magnetic fine particles from a non-magnetic fine powder by high gradient magnetic separation under dry condition was studied. The dry magnetic separation has been partially put to practical use in the separation of iron from waste, the mining field, the food industry and so on. However, in the application of high-gradient magnetic separation (HGMS) with a stronger magnetic force,...
Quench detection is an indispensable part of the superconducting electrical device to ensure its safe and stable operation. For HTS cables with a length of several kilometers, Distributed Temperature Sensing (DTS) based on Raman Optical Time Domain Reflection (R-OTDR) has irreplaceable capacity such as continuous spatial measurement and long sensing distance, but the optical fiber needs to...
This presentation shows the effect of soldering between YBCO tapes on the inter-tape resistances in the stacked cables composing of dozens of YBCO tapes. The research and developments of a stacked cable with multiple YBCO tapes are ongoing as a candidate for large-scale conductors for fusion experimental devices. In this study, the inter-tape coupling losses in the cable composing of stacked...
During the years of ITER conductors qualification phases, samples from all domestic agencies were tested. Some of these tests were focused on characterizing the AC losses properties of the ITER conductors. The data produced originate from various facilities (SULTAN, University of Twente, CERN…), using different experimental protocols, for a large number of samples. The result is thus a...
This paper describes the design and the test result of the world’s most compact rotating gantry for heavy ion therapy system mounted with superconducting bending and focusing magnets that is successfully installed in East Japan Heavy Ion Center Faculty of Medicine, Yamagata University, Japan. Rotating gantry is a cylindrical irradiation equipment with magnets for beam transport and beam...
By the merits of self-stable levitation, low energy cost and no-contact friction, high-temperature-superconducting (HTS) pinning maglev system has a great potential to become an ultra-high-speed transportation. Recently, with the mature of the HTS pining maglev technology, the first HTS maglev engineering prototype vehicle was successfully established in our group. As the most important factor...
A method of removing microplastics from seawater using electromagnetic force was devised and its feasibility was demonstrated by calculation. Plastic is difficult to decompose and puts a heavy load on the marine environment. In particular, plastics smaller than 5 mm are defined as microplastics, which are carried over long distances by ocean currents and cause global pollution. The development...
A commercial micrometric Cu powder is mixed with Ag nanowires (diameter 0.2 µm, length 30 µm) synthesized in-house, in order to prepare a powder with a Ag content of 1 vol. %. Two powder batches are prepared for consolidation into cylinders (diameter 8 mm, length 33 mm) by spark plasma sintering.
One cylinder is sintered at 400 °C, where the solubility of Ag in Cu is below 0.1 vol. %, which...
Here we have studied the performance and quench properties of a large (outer diameter: 901 mm; winding pack: 44 mm thick × 50.6 mm high) conduction-cooled, react-and-wind, MgB2 superconducting coil. Minimum quench energy (MQE) values were measured at several coil operating DC currents (Iop ), and distinguished from the minimum energy needed to generate a normal zone (MGE). During these...
High field superconducting magnets require a large number of ampere-turn in their windings. To avoid large self-inductances in such magnets they must be wound using superconducting cables. Compared to other currently available HTS cables REBCO Roebel and CORC cables have their strands transposed or twisted which reduces both their ac losses as well as magnetization. This improves field...
Fusion for Energy (F4E), the European Domestic Agency for ITER, is responsible for the supply of ten out of 18 Toroidal Field Coils installed in the ITER machine. This article gives an update of the status of the cold test of the winding packs and their insertion into the Coil Cases being the last work package of the TF magnet production performed under the framework of an F4E contract...
In this paper, a REBCO thin film superconducting wire was fabricated by depositing materials with different specific resistance values (Ag) on REBCO superconducting wire, using the “RF Sputtering Deposition Method” with micro-range thicknesses to form the outer layer. Then the fabricated REBCO superconducting wire were subjected to basic characteristics tests (measurement of their temperature...
A Wireless Power Transmission (WPT) system for a railway vehicle has been investigating to reduce the greenhouse gas emissions in a diesel vehicle. Since the WPT system for the railway vehicle is required to transmit the electric power of several hundred kW in a short time, it is difficult to suppress heat generation by the internal resistance of a copper coil. Therefore, we have investigated...
HTS flux pumps enable superconducting currents to be directly injected into a magnet coil without the requirement for thermally inefficient current leads. As exciter of high temperature superconducting synchronous motor, HTS flux pumps will reduce the cryogenic volume and improve the efficiency of the HTS machine. With the air gap between the flux pump and the HTS stator increases, the...
This paper describes a design of a Vertical-ring High Gradient Superconducting Magnetic Separation (VHGMS) magnet for recovery of the magnetic ore and purification of non-metallic minerals. Compared to the conventional design which uses copper wires, using superconducting magnet can help reduce the energy consumption and increase the magnetic field. The first part of this paper introduces the...
Superconducting magnet protection must address two main areas of the magnet and circuit performance, namely Conductor Hot-Spots and Circuit Voltages. Both hot spot and voltage operational maximums are during the superconductor's transition called a Quench. Historically high voltages have resulted in many damaged and destroyed magnet coils so reducing voltages is a preferred direction for...
We propose a new active feedback control method to quickly charge no-insulation(NI) magnets, as well as sustaining thermal stability. The main feature of our suggested method is controlling ramping rate of the magnet to minimize consecutive Joule heating induced by the radial leakage current and resistive joint. The suggested method to be applicable for the iron core NI coils, dynamic...
Nb3Al has better the strain properties than that of Nb3Sn, but it is difficult to manufacture as a wire. In recent years, a research group of the National Institute for Materials Science (NIMS) in Japan has developed a new shape of ultra-fine and flexible Nb3Al superconducting. Jelly-rolled Nb/Al composite monofilamentary wires with an outer diameter of 30 m, and multi-strand wires were...
It has been fifty years since the first papers on the effects of magnetization in the superconductor in an accelerator magnet field quality were measured. The effects of conductor magnetization are most pronounced at low fields. By late 1971, a reliable method for estimating the effects of superconductor magnetization on the field quality in accelerator magnets was developed. A review of...
The superconducting tape stack has increasing impact on the applied superconductivity community due to the high field and current applications such as plasma confining magnets. The interlayer resistance of the stack, however remains a problem for the Coated Conductors (CCs) due to the ceramic buffer layer, which causes totally different behavior of the stack of CCs and the traditional low...
Abstract: The YBCO superconducting coils will cause complex deformation, and even moving between layers under the large Lorentz forces during energization. These will further disturb the magnetic field quality and the operating safety and stability. A more accurate estimation of the magneto-mechanical behaviors of YBCO coil during excitation is a crucial one. However, the conventional finite...
Metal plates are applied in high-temperature superconducting (HTS) magnet to provide a mechanical support and conduction cooling. The electromagnetic coupling between the metal plates and HTS coils has a considerable influence on the discharge operation of HTS coils during quench protection. In this paper, a multi-physics model is developed using circuit- field coupling method to study the...
Superconducting Magnetic Energy Storage (SMES) has the advantages of fast response speed, large energy storage density and low loss, which is suitable for dynamic power compensation of power systems. During operation, the superconducting magnet exchanges power with the AC grid through the power conditioning system (PCS). The PCS generally adopts a PWM converter based on a high-frequency ...
The magnetic center alignment is extraordinarily important before put a new ion-source into operation. Misalignment of ion-source may cause arc chamber destroyed. We take two methods to measure and align the ion-source superconducting magnet based on the cryostat bore in IMP. The required offset between ion-source magnetic center and mechanical center of warm bore is less than 0.5mm.
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For fluctuation suppression and energy compensation of the power system of the particle accelerators Booster and Nuclotron of NICA complex at JINR, 3 inductively coupled SMES coils are adopted. ASIPP is responsible for one of the three coils with 1 MJ energy storage. The inner diameter of the SMES coil is optimized to be 680 mm. The operating current is about 6 kA level and the pulse period is...
9 ITER TF coils are being manufactured in Japan for ITER project. Each TF coil consists of 7 Nb3Sn conductor double-pancakes (DP). In heat treatment of DP, strand witness samples are heat-treated with DP simultaneously and then their critical current (Ic) is measured to confirm soundness of the heat treatment. Recently, heat treatment of all of 63 DPs has been successfully completed under...
Since the 2G HTS tapes are made by a multi-layered thin film process, delamination occurs easily when stress is applied in the vertical direction of the tape. That is, in the cooling process of the superconducting coil, delaminations occur in the multi-layered HTS tapes when the stress value due to the difference in the thermal contraction rate of each material constituting the HTS tape is...
The Future Circular Collider would require a high-field septum magnet with a possibly thin blade for the extraction of the 50 TeV proton beam from the ring. One of the two baseline concepts in the conceptual design report is the "superconducting shield" (nicknamed as SuShi) septum, utilizing a zero field cooled, passive superconducting shield in order to create a zero-field channel inside the...
SIGRUM (Superconducting Ion Gantry with Riboni’s Unconventional Mechanics) project comes from the strong collaboration between ‘Centro Nazionale di Adroterapia Oncologica’ (CNAO), in Pavia, Italy, and CERN. This centre, relying on CERN experience in accelerator particles, wants to improve cancer treatments with a novel superconducting ion gantry structure.
The magnet is operated at a...
No-insulation (NI) winding technique shows superior electrical and thermal performance for high temperature superconducting (HTS) coils compared with the insulation winding technique. However, the NI HTS winding technique is uncertain about the thermal contact resistance between winding turns because the HTS wire has various surface conditions such as roughness and oxidation. In this paper,...
Heavy-ion radiotherapy has a high curative effect and low burden on patients, so it has been spreading in recent year. On the other hand, since heavy-ion radiotherapy system have large apparatuses such as injector, synchrotron, and rotating gantry, it is necessary to downsize these apparatuses in order to further wide spreading. Therefore, a project to develop a next generation small facility...
High Temperature Superconductors (HTS) is a promising option for high current Cable-In-Conduit Conductors (CICC) for large high-field magnets. CICC are often constructed from several HTS strands which themselves are formed from individual HTS tapes. Quench propagation is CICCs is currently under intensive investigation, and it can be predicted by modelling the entire structure. However, for...
To prevent global warming, CO2 emission by aircrafts is required reduction. For that purpose, the electric propulsion system is focused on as a promising technology. That system enables the aircraft to adopt distributed propulsors which have a great advantage from the viewpoint of aerodynamics. That system contains rotating machines; however, the conventional ones cannot satisfy the stringent...
In September 2018, China Spallation Neutron Source (CSNS) passed the national acceptance and started stable operation. Many scientific achievements have been made, but more and more experiments require accelerators with higher beam quality. Based on the current Lattice layout and further research, an alternative upgrade plan is proposed for RCS, which will become the formal design scheme of...
An infiltration and reaction (IR) process realizes the dense MgB$_2$ bulk without the external physical pressure. The trapped field, $B_{\rm T}$, of MgB$_2$ bulk prepared by the IR process was 2.4 T at 15.9 K, which was as high as that of MgB$_2$ bulk prepared by in-situ hot isostatic pressing method [1]. However, we found quite a large amount of unreacted micrometric B particles due to the...
A quasi-microgravity space, exploiting a large magnetic field in combination with a large field gradient, is considered for potential applications such as protein crystallization and cell culture without natural convection caused by gravity. To provide a high magnetic field in a more cost-effective way, large-single grain bulk superconductors – such as the RE-Ba-Cu-O (RE: rare earth element or...
The intermittent characteristics and low system inertial are two major problems for the renewable energy sources (RESs) dominated power system. This paper proposes the novel idea of integrating the wind and photovoltaic power generators with a superconducting magnetic system (SMES) as a whole to behave as a grid-forming renewable energy system. The proposed grid forming system can provide...
Since the beginnings of NMR spectroscopy, the exceptionally successful method to analyze the chemical structure of solids and molecules in solution, experimentalists requested ever larger magnetic fields for their instruments, primarily to improve their resolution and their signal-to-noise ratio. While a succession of low-Tc superconductors – NbTi and a range of Nb3Sn wire types – were the...
This summer the US HL-LHC Accelerator Upgrade Project (AUP) reached an important milestone by completing 50% coil fabrication. AUP is fabricating half of the low beta quadrupoles (MQXFA) for the High Luminosity LHC (HL-LHC) at CERN. These magnets will be used in Q1 and Q3 Inner Triplet (IT) elements of HL-LHC. CERN is fabrication the magnets for Q2a and Q2b IT elements. The AUP effort is...
We present the operation result of a liquid-helium-free 23.5-T/φ12.5-mm-cold-bore magnet prototype composed of a stack of 10 no-insulation (NI) REBCO double-pancake (DP) coils: eight middle coils of 6-mm wide and two end coils of 8-mm wide tape. All the tapes have only 1-µm-thick copper layer on each side to overcome the conductor thickness uniformity issue and enhance the mechanical strength...
Korea Medical Device Development Fund (KMDF) launched a national project to develop a high-temperature superconductor magnet for magnetic resonance imaging (MRI) in 2020. This project's ultimate target is to develop a 6 T 320 mm high temperature superconductor (HTS) magnet. Major concerns in developing the MRI magnet in terms of electromagnetic dynamics are the time-varying field uniformity...
New high field and large-aperture quadrupole magnets for the low-beta inner triplets (Q1, Q2, Q3) are being built as part of the high-luminosity upgrade of the Large Hadron Collider (HL-LHC). These new quadrupole magnets are based on Nb3Sn superconducting technology. US Accelerator Upgrade Project (US-AUP) is producing the Q1 and Q3 cryo-assemblies; a pair of ~ 5 m long magnet structures...
This work concerns the development of non-insulated (NI) HTS magnets at the Paul Scherrer Institute (PSI), Switzerland.
The Swiss Light Source (SLS) synchrotron at PSI uses superbend magnets as a brilliant source of X-rays. As part of an upgrade of the SLS, two LTS superbends are being constructed. These NbTi-based magnets will each consist of a pair of racetracks to generate the desired...
In recent years, remarkable progresses have been made in the R&D efforts for HTS high-field magnets. The screening-current-induced magnetic field (SCIF) and mechanical stress/strain (SCIS) in REBCO coils are raising growing concerns. This study presents experimental and theoretical analyses on the SCIS in two REBCO coils, with and without over-banding structures, as inserts in an LTS...
The High-Luminosity project (HL-LHC) of the CERN Large Hadron Collider (LHC), requires low β* quadrupole magnets in Nb3Sn technology that will be installed on each side of the ATLAS and CMS experiments. After a successful short-model magnet manufacture and test campaign, the project has advanced with the production, assembly, and test of full-size magnets. In the last two years, two CERN-built...
HTS is valuable for future detector magnets as it allows operation at elevated temperatures and magnetic fields. However, due to slow propagation of normal-zones, quench protection remains a challenge. Non-insulated coil technology offers a potential way forward, but controlling the associated ramping time constant is still an unresolved challenge. This study offers a potential way to have...
The high-strength substrate within REBCO contributes to its selection for use in the NHMFL 40 T all-superconducting magnet. To confidently scale up to a 40 T user magnet, both quench protection and cyclic fatigue are among the technologies that require successful demonstration. Here, numerous test and simulation results from two-in-hand wound, double-pancake stacked, insulated mid-scale test...
High-temperature superconducting (RE)Ba2Cu3O7-x (REBCO) coated conductor (CC) tapes are known for their capacity to tolerate high tensile stress under applied uniaxial tension, typically in the range of 600-700 MPa at 77 K, while mediocre level under pure bending (a.k.a., easy bending). Once utilized in coil, however, there is a limit to the value of the allowed strain/stress before...
We have succeeded in operating a 25 T cryogen-free superconducting magnet (25T-CSM), which consists of LTS outsert coils and Bi2223 insert pancake coils. As a next step, an upgrading of 25T-CSM to 30T-class CSM is considered by replacing the Bi2223 insert coils with REBCO coils, since REBCO tapes have better mechanical and in-field critical current properties. In a design of the 30T-CSM, the...
INFN is developing at the LASA lab (Milano, Italy) the High Order (HO) corrector magnets for the High Luminosity-LHC (HL-LHC) project, which will equip the new interaction regions. All the HO correctors, from skew quadrupole to dodecapole, are based on a novel superferric design, never used so far in high energy colliders, which allows a relatively simple, modular, and easy way to construct a...
In order to achieve high intensity and compact multifunctional cyclotron, the behavior of the non-circular coil in a high magnetic field at 4.2 K, and the reinforcement of it have been investigated. Two types of isosceles triangle shaped double-pancake coils; a coil with reinforcement due to Yoroi-coil (Y-based oxide superconductor and reinforcing outer integrated coil) structure and a coil...
Large aperture beam separation dipole (MBXF) will be constructed as a Japanese contribution for the High-Luminosity LHC upgrade. Those magnets will be installed at both sides of two interaction points, ATLAS and CMS. The required field integral is 35 Tm with the coil aperture of 150 mm. Nominal dipole field of 5.6 T at the nominal current of 12 kA is produced at 1.9 K by Nb-Ti based...
MCBXFB magnets are nested orbit combined correctors for the upgrade of the LHC. The first three magnets have been manufactured at CIEMAT and assembled at CERN, in the framework of the HL-LHC project. The power tests performed on the first prototype showed that the behaviour when the dipoles were individually powered was excellent, but the training to reach nominal currents in combined...
A 14 T whole-body MRI superconducting magnet is currently being designed at the Institute of Plasma Physics Chinese Academy of Sciences. The main coils will be wound with the Nb3Sn Rutherford cable-in-channel conductors, actively shielded, and operate at 1634 A to produce a central field of 14 T in an 840 mm warm bore. The magnetic field homogeneity is 5 ppm in a 45cm DSV. The inductance is...
Advanced Conductor Technologies has been developing high-temperature superconducting (HTS) Conductor on Round Core (CORC®) cables and wires wound from ReBa2Cu3O7- coated conductors for use in high-field magnets that would ultimately operate at fields exceeding 20 T. CORC® cables and wires have matured into practical high-current and high-current density magnet conductors that are being...
From a magnet designer’s point of view Bi-2212 round conductor is, in many aspects, the ideal candidate for high field magnets. Besides very high critical current densities that exceed specification for conductor of the Future Circular Collider (FCC) of 1500 A/mm2 in 16 T background, it offers two particular advantages over other HTS conductors, namely that it is available as an up to one mile...
The U.S. Magnet Development Program (USMDP) is developing Canted-Cosine-Theta (CCT) magnet technology for future high field accelerator magnets. The CCT concept limits Lorentz force accumulation by placing turns within precision-machined grooves that are separated by ribs and a spar that intercept forces, substantially reducing the stress in the conductor. CCT technology has been advanced...
Future high energy particle colliders are under study, with a first goal of 16 T dipoles, which is believed to be the practical limit of $Nb_3Sn$ magnets. Another more ambitious goal is to aim for 20 T dipoles. This very high field would require High Temperature Superconductors (HTS), such as Bi2212 or REBCO. Their substantially higher cost necessitate anyways the use of Nb3Sn for an...
R2D2, the Research Racetrack Dipole Demonstrator, is a short model being developed within a collaboration between CEA Paris-Saclay and CERN aimed at developing key technologies for future high field 16 T $Nb_3Sn$ magnets for particle colliders. In the particular case of block-coil designs, two different cable grades are wound in the same coil layer, in order to maximize the current density,...
A dipole magnet generating 20 T and beyond will require high-temperature superconductors such as Bi$_2$Sr$_2$CaCu$_2$O$_{8−x}$ (Bi-2212) and REBa$_2$Cu$_3$O$_{7-x}$ (RE = rare earth, REBCO). Symmetric tape round (STAR™) wires based on REBCO tapes are emerging for such an application especially because of their unique tolerance to bending to a radius as small as 15 mm. Although STAR™ wires...
A project aiming to fabricate an operational Nb3Sn superconducting undulator for the storage ring of the Advanced Photon Source at Argonne National Laboratory is under way. The Nb3Sn undulator has a design magnetic field of 1.2 T and a nominal operation current of 850 A. The maximum magnetic field on the conductor is about 5 T. With large critical current densities, the 35 µm subelement size...
Double-Stator-Single-Rotor (DSSR) surface mounted Permanent Magnet Synchronous Motor (PMSM) has the advantages of small size, light weight and high reliability. However, there are problems of large torque ripple and abundant back-EMF harmonic content. In order to improve the electromagnetic performance of the motor, a double-stator single-rotor field modulated motor (DSSR FMM) with high...
Superconducting magnets used in particle accelerators produce magnetic fields of high precision and uniformity to bend or focus the particle beam. For such magnets, the development of accurate and efficient numerical methods for the evaluation of the magnetic fields is of high importance. This work presents a hybrid Finite/Boundary Element Method (FEM/BEM) scalar potential formulation,...
Construction of a new primary proton beam line, which is called B-line, started in 2013 at the J-PARC Hadron Experimental Facility. The B-line is branched at the middle of an existing primary proton beam line (A-line) in the beam switching yard (SY), which is the connecting tunnel between the Main Ring (MR) and the Hadron experimental hall (HD-hall). At the branching point, about 0.1% of the...
Magnetic gear (MG), as a kind of non-contact transmission component, has many advantages, such as no friction, oil-pollution free, low maintenance and easy installation, and so on.This paper proposes a novel coaxial magnetic gear (CMG) with eccentric permanent magnet structure and unequal Halbach arrays for achieving sinusoidal air-gap flux density and high output torque. The proposed model...
The magnetic field modulation type magnetic gear composite motor is a new type of motor integrating magnetic gear and permanent magnet brushless motor. Its advantage is that it has higher torque density and efficiency, and has a good application prospect in the field of low speed and large torque. According to the principle of magnetic field modulation, the air gap magnetic field of the...
A quench detection system was developed for protecting and monitoring the superconducting solenoids for the Muon-to-Electron Conversion Experiment (Mu2e) at Fermilab. The quench system was designed for a high level of dependability and long-term continuous operation and is based on three tiers: Tier-I, FPGA-based Digital Quench Detection (DQD); Tier-II, Analog Quench Detection (AQD); and...
A tri-axial high temperature superconducting cable has the advantages of small size, large transmission capacity, low AC loss and high economic efficiency in power transmission of urban city. The essential difference between superconducting cable and traditional cable lies in their unhindered current-carrying characteristics. But when carrying alternating current or changing electromagnetic...
AC loss reduction is essential to apply high temperature superconducting (HTS) conductors to power devices. We have studied the effect of AC loss decrease of CORC that is a low-loss and high-current conductor. The currents through CORC are equally distributed to the CORC strands (HTS tapes) because the strands are helically arranged around a cylindrical former. We have confirmed that the AC...
Rapid-cycling synchrotrons (RCSs) are desired as the main component of radiotherapy facilities for cancer treatment in order to meet growing patient numbers. Superferric magnets consisting of high temperature superconducting (HTS) coil windings and iron cores are considered to be an effective solution for reducing construction cost and electricity consumption for RCSs. However, superferric...
The onboard high temperature superconducting (HTS) magnet of electrodynamic suspension (EDS) train suffers from the external magnetic fields generated by the ground coils including the suspension coils, propulsion coils and even generator coils. In such case, the ac losses will be produced in the HTS magnet and lead to a rise in temperature, possibly affecting the operation stability of the...
R&D on joints between superconducting wires or tapes is one of the most important issues for the development of large-scale superconducting applications such as magnet, rotation machine and so on. Although the electro-magnetic properties between superconducting joints have been evaluated in several ways, the interfacial structure of the joint should also be investigated in order to sufficient...
The No-insulation (NI) REBCO as an insert magnet has been applied to overcome the field limitation of LTS NMRs. So far, NI REBCO pancake coils have shown a “self-protecting” characteristic in experiments and, consequently, basic mechanism of self-protecting from thermal runaway has been widely studied by analyses under a low magnetic field or cooled by liquid nitrogen. However, several HTS...
High current cables for large fusion magnets can be composed of hundreds of tapes. A convenient way to deal with such large number of tapes is multi-stage cabling. The stack of tapes is a basic element for the first stage of various high current cables designs. AC losses have been evaluated analytically in the limits of very low and very high sweep rates, providing a global overview of losses...
Abastract: Currently, a new gas-filled recoil separator Spectrometer for Heavy Atoms and Nuclear Structure 2 (SHANS2) is being developed and designed at IMP (Institute of Modern Physics, Chinese Academy of Sciences). It will be used to synthesize and study the superheavy elements, including their physical and chemical properties. The SHANS2 include two dipole magnets and three quadrupole...
One of the technical issues in the application of High Temperature Superconducting (HTS) tapes is the need to wind long tape sections with uniform electric properties along their length. In recent years, the No-Insulation (NI) winding technique for HTS coils is emerging as a valid alternative to conventional insulated coils, as it allows a more effective current redistribution from the most...
Low resistivity joint technique for high-Tc superconducting (HTSC) tapes is one of the most indispensable techniques for practical applications. At the present time the solder joint technique is widely used for joining HTS tapes for the non-superconducting joint. However, in the case of a joint using a solder, the resistance across the joint cannot be very low because of relatively high...
Stress management techniques have shown great potential to mitigate the high level of stress appearing in high field accelerator magnets, which is especially critical for stress-strain sensitive superconductors, such as Nb3Sn or HTS. The Canted-Cosine-Theta (CCT) concept provides an effective method to intercept the Lorentz forces of each turn, leading to a lower stress accumulation...
In recent years, there has been a renewed interest in the suitability and use of the Bi-2212 wires in various fields of application. Many studies highlight the possibility to use Bi-2212 for high magnetic field magnets above 18-20 T.
The purpose of this work is to study the electrical properties of Bi-2212 wires at temperatures above liquid Helium. The samples were obtained via a novel...
No-insulation (NI) technique has been proved to be an available approach for improving the thermal stability as well as the highest operating current of the high-temperature superconducting (HTS) coil. Nevertheless, the NI HTS coil suffers from a non-negligible charging delay inevitably. To address this issue, the parallel co-wound technique is a possible way. For investigating the performance...
Whole body ultra-magnetic field 14 T magnetic resonance imag-ing (MRI) magnet is now under design at Institute of Plasma Physics, Chinese Academy of Sciences, the main coil based on the preliminary designed of Nb3Sn Rutherford cable in Channel Conductor (RICC). Rutherford cable is a core components of the conductor. During the fabrication process of Rutherford cable, the strands were subject...
In the framework of the High-Luminosity Large Hadron Collider (HL-LHC) project, 11 T dipole and MQXF quadrupole magnets employing Nb3Sn technology have been tested in short and long test configurations. Nb3Sn magnets are more sensitive than NbTi magnets to a potential degradation of their conductors during production, testing and cycling operation. In the SM18 magnet test...
For future 20+ T accelerator type magnets, ReBCO tape based conductors are ideal for their capability of carrying high current densities in high magnetic field. At CERN, demonstrator dipole magnets using ReBCO conductor are being developed in order to study the feasibility of this technology. A key problem in such magnets is how to realize the coil ends when using ReBCO tape conductor without...
There is a huge energetic potential associated to ocean waves, expressed in terms of the power per wave meter length that can be harvested, up to 60-80 kW/m in many areas near to the shore of populated areas. Among the different devices proposed to extract that power, the most extended ones are the Point Absorbers, based on the linear displacement between two bodies for which the use of...
The construction of European demonstration power plant (DEMO) aims to employ high temperature superconductors (HTS) as the main magnets to avoid the requirement of large amounts of helium for the cooling system. The central solenoid coils which is transported with AC current in the reactor should be ensured of their operation condition to avoid quench phenomenon under a high temperature...
The super high field magnets using superconducting wires have been promisingly applied for thermonuclear fusion power generation such as Korea Superconducting Tokamak Advanced Research (KSTAR) and International Thermonuclear experimental reactor (ITER) systems. The quench detection system (QDS) is essential for high reliability in the super high field magnet facilities. Generally, the quench...
There are demands for mobile microwave power sources for different applications, such as the rock melting and drilling, for example. The 28 GHz gyrotron has been proposed as radiation source for such purpose [1]. For frequency ~ 28-30 GHz or more magnetic field ~1-3 T are needed for resonance interaction of the electron beam with eigenmodes of a circular waveguide at gyrodevices. Magnetic...
High energy physics research will need more and more powerful circular accelerators in the next decades, in order to explore unknown regions of particle physics. It is therefore desirable to have dipole magnets able to produce the largest possible magnetic field, in order to keep the machine diameter within reasonable size. A 20 T dipole is considered a desired achievement, since it would...
Recently, the development of the concept project of the high magnetic field (HMF) tokamak continues in the Russian Federation. The value of the magnetic field on the plasma axis in the device is about 8 T. The maximum field on the winding of the toroidal field coils is about 16 T. The generation of a high magnetic field in a limited space of tokamak-type device with a given aspect...
Striation (multifilament) is an effective way to reduce AC losses in the coated conductors for the applications of magnets or electrical power devices. Considering the robustness of the striated coated conductors, it is preferred to have some transverse conductance like copper between superconductor filaments. In such a conductor, however, the striation works for AC loss reduction only after...
The reduction of large AC losses in ReBCO coated conductors caused by their wide tape shape is a critical issue for their power applications. In principle, striating the wide superconductor layer of a coated conductor into narrow filaments (multifilament) is effective for the AC loss reduction. However, this approach is effective only when the filaments are decoupled electromagnetically, i.e....
In this paper, a new configuration of self-shielding DC HTS cable with a “sandwich” structure by interleaving winding is proposed. The distributions of the magnetic field and the critical currents in traditional DC HTS cable and self-shielding DC HTS cable are analyzed and compared in detail. The simulation results show that the self-shielding DC HTS cable can minimize the outer magnetic field...
The use of high temperature superconducting (HTS) materials is promising for both DC and AC power applications and for high field magnets. However, HTS coils must be carefully protected against quench, since the formation of hot spots can damage the materials even more severely than in the case of low temperature superconducting coils. A possible solution to this issue is offered by the use of...
High-temperature superconducting (HTS) magnets have been widely studied for practical applications of NMR, MRI, and medical accelerators. 2nd-generation HTS, REBCO (Rare-Earth Barium Copper Oxide), coated conductors (CC) have a high critical field and excellent electrical properties, compared to other superconducting conductors. REBCO pancake coils using the no-insulation winding technique can...
This study analyzes the current bypass mechanism of a metal stitching smart insulation (SI) coil rolled by coating vanadium oxide (V2O3) on a metal stitching wire prepared by generating micro-holes into a second generation (2G) high-temperature superconducting (HTS) wire using a laser and by filling the micro-holes with metal solder material. Results showed that the metal stitching wire with...
Whole body ultra-magnetic field 14 T magnetic resonance imag-ing (MRI) magnet is now under design at Institute of Plasma Physics, Chinese Academy of Sciences, the main coil based on the preliminary designed of Nb3Sn Rutherford cable in Channel Conductor (RICC). Rutherford cable is a core components of the conductor. During cabling the strands are inevitably experience plastic deformation that...
High field magnet technologies are supported by the development of advanced superconducting (SC) cable constructed from the composite SC tape. The SC tapes in the helically wound composite cable experience flatwise as well as edgewise bending load together with tensile one. We analyzed precisely the influence of uniaxial tensile load to critical current (Ic) of BSCCO tapes, where the...
In the framework of the consolidation of the Antiproton Decelerator (AD) Target Area it was decided to replace the two original normal conducting quadrupoles used for the final focussing of the proton beam before the target by two 1-m-long quadrupoles based on permanent magnet technology. Their gradient is adjustable from 35 to 45 T/m inside an aperture of 60 mm in diameter. This paper...
Compared to low temperature superconductor (LTS) based fusion conductors, the use of high temperature superconductors (HTS) offers the possibility to increase the magnetic field strength in future fusion reactors, allowing higher flux swing or even more compact fusion reactors. REBCO, the most promising HTS material, is commercially available as coated conductor tape. Opposed to LTS wires,...
Particle spin physics research at Nica collider deals with polarized proton and deuterium beams. Special solenoids are proposed to control the spin direction of the polarized beams in NICA. Spin direction can be controlled by adjusting the integral of axial magnetic field of the solenoids. We present design results for 6T polarization control superconducting magnets for NICA collider. The...
A 14T physical property measurement system (PPMS) magnet with cryogen free is being developed in Institute of Electrical Engineering, Chinese Academy of Sciences (IEE, CAS). Unlike steady-state magnets such as NMR, MRI, the PPMS magnet is required to be excited frequently and the excitation rate usually needs very high, for example in 30min to reach the full magnet field. The fast excitation...
Large aperture superconducting combined function magnets with the magnetic rigidity of 13Tm will be utilized in the Spectrometer-Ring for the HIAF (High Intensity heavy-ion Accelerator Facility) project. The magnet is designed to provide a dipole field of 3.0 T and a quadrupole field of 11.3 T/m in a large aperture of 240 mm. The Canted Cosine Theta (CCT) superconducting magnet had been well...
This paper describes a simple, compact and cost-effective capacitor pulse power supply, which only uses a single magnet coil and two capacitors of different voltage and capacity levels to form a special circuit structure. It can realize the pulse magnetic field similar to the flat top wave, so as to meet some scientific experiments that require higher magnetic field strength and stability....
Flat-top high magnetic field (FTMF) is a significant research method for physics, chemistry, biology and other scientific fields with the demands for higher magnetic intensity, longer flat-top pulsed width and a lower ripple. To meet these demands, a new FTMF system based on multiple-capacitors power supply has been realized at the Wuhan National High Magnetic Field Center in March 2021....
Large-size aluminum alloy rings are widely used as connector, transition ring and reinforcing structure in aerospace and other fields. Their performance determine the service life, assembly accuracy and reliability of the equipment directly. However, the residual stress introduced during the manufacturing process lead to the structural instability and poor mechanical properties of the aluminum...
Coated superconductor magnets have already proved their feasibility in electrodynamic suspension (EDS) application as the on-board magnet, making the liquid-helium-free EDS train become possible. This paper designs a racetrack REBCO magnet served as the on-board magnet of EDS train, including the designs of both the REBCO coil composed of eight double pancake (DP) coils and the tailored...
Superconducting undulator (SCU) technology has been in use at the Advanced Photon Source since 2013. Due to the successful and reliable operation of the existing SCUs, the Advanced Photon Source upgrade project has decided to expand the use of NbTi-based SCUs. The first new magnets to be designed and fabricated are 1.9 m long with a period length of 16.5 mm. NbTi superconductor is used for...
FASER, the ForwArd Search ExpeRiment, is designed to search for new, yet undiscovered, light and weakly-interacting particles and study the interactions of high-energy neutrinos. Three dipoles are required to achieve sufficient separation of pairs of oppositely charged, high-energy Standard Model particles originating from decays of new physics particles. The first magnet is 1.5-m-long and...
The CSR external-target experiment (CEE) will be China’s first self-developed nuclear research experimental facility operating in the GeV regime based on the large-scale scientific facilities HIRFL-CSR. One of its core components is a dipole magnet with a large gap and wide acceptance. Unlike traditional large spectrometer magnets, the physical target of the CEE requires a highly stable,...
The NUCLOTRON type cable has been chosen for developing a fast cycled superconducting dipole for the booster ring of the HIAF project at IMP. The splices of the cable are key components for the magnet. A design which has a resistance about 10-9 Ohm and is easy to be fabricated is developed. The structure of the joint is optimized with Opera software. And reliable fabrication process is...
In the aluminum industry, development of highly efficient and fast heating methods of aluminum billets is expected. The induction heating by rotating the aluminum billet in strong DC magnetic field generated by HTS coils is one of the candidates for the heating methods in the aluminum extrusion processes, since this method has the large heating capacity with higher energy efficiency and faster...
Reducing AC losses in coated conductors is one of the important issues for HTS applications to electric power devices and magnets. Multifilament structure is a method to reduce AC losses. From the view point of improving the robustness of a multifilament coated conductor for local normal transitions, it is preferable to have a finite transverse conductance. When copper is plated over the...
We have been developing radiation-resistant warm magnets insulated by a Cyanate ester resin. We developed a glass fiber cloth prepreg tape using Cyanate-ester pre-polymers supplied by Mitsubishi Gas Chemical Corporation INC. The proton beam irradiation test was carried out for the evaluation of the radiation hardness. We prepared cured resin samples of Cyanate ester, Bismaleimide Triazine...
It is expected to build a sustainable social system that uses "hydrogen" as a fuel to generate electricity without emitting CO2. To realize this, technology for storing a large amount of hydrogen is indispensable, and storage as liquid hydrogen is ideal. However, the efficiency of the cooling device in the temperature range around 20 K required for long-term storage with liquid hydrogen is...
High-temperature superconductors such as REBa2Cu3O7-x (REBCO) can generate strong magnetic fields that are promising for applications in particle accelerators and compact fusion reactors. Lawrence Berkeley National Laboratory is developing magnet technology-based multi-tape REBCO cable conductors. Traditionally, voltage taps are installed in superconducting magnets. The voltage signals due to...
Dynamic loss is an essential parameter to consider for the design of high temperature superconducting (HTS) synchronous machine windings. For HTS coated conductors (CC), the existing definition of dynamic loss only considers the HTS layer, the validity of which compound with magnetic substrate is questionable. In response to the above concern, by use of the H-formulation based numerical...
Due to the extensive application of soft magnetic materials in transformers, motors, reactors and other electrical equipment, the research of accurate iron loss prediction method becomes an indispensable part to ensure the safe operation of power system and to realize the optimal design of electrical equipment. However, the development of appropriate methods for predicting iron loss is...
The world’s first full-sized high-temperature superconducting (HTS) Pinning magnetic levitation (maglev) engineering prototype train was officially launched in SWJTU, Chengdu, China in 2021. This prototype provides strong proof for the feasibility of engineering application of HTS pinning maglev in civil train. This prototype shows the basic load and low speed operation capability of HTS...
Development of high temperature superconducting REBa2Cu3Oy (REBCO, RE: Y and rare earth) coated conductors (CCs) would enable cost-effective magnet applications in rotation machines, generators for wind turbine and magnet use in medical imaging machines. To use for these applications, precipitates and structural defects with nano-meter size have been introduced in REBCO films to enhance...
GdBa2Cu3O7-δ (GdBCO) has high critical current density (Jc) of the order of 106 A/cm2 at 77 K in self-field and higher critical temperature (Tc) than that of YBa2Cu3O7-δ. Therefore, GdBCO coated conductor (CC) has been expected as a promising wire material. For the wire application, superconducting joint of CC has been required to lengthen them. In our previous work, superconducting joint of...
China Fusion Engineering Experimental Reactor (CFETR) is a major scientific project independently designed and developed by China and jointly with international cooperation. Engineering design and project infrastructure construction are currently underway. The design goal of CFETR is 1.5-2.0 GW fusion power, and the central magnetic field is up to 17 Tesla, which is much larger than the design...
V2O3 has been studied as a smart insulation material for 2G high-temperature superconducting (HTS) coils owing to its remarkable metal-to-insulator transition (MIT) upon heating or cooling via a critical temperature (Tc) of ~160 K. The smart insulated (SI) coil regulates its function according to the MIT properties of V2O3. At temperatures below Tc, V2O3 acts as an insulator, whereas it...
The Facility for Rare Isotopes Beams (FRIB) employs an advanced fragment separator for the efficient production and purification of the in-flight rare isotope beams. At the first stage, the incoming primary beam from a production target experiences an initial separation from the products of interest. A large phase secondary beam needs to be purified and focused with magnetic multipole elements...
The design and operation of resistive high field magnets require research and development in materials science, power supply engineering and instrumentation. Additionally, their energy efficient operation has become a growing constraint. The French National High Magnetic Field laboratory at Grenoble (LNCMI) is continuously improving its high magnetic field platform in order to satisfy the...
In REBCO tape having multi-layered structure, resistance of Cu/Ag and Ag/REBCO interfaces (interface resistance) is one of the major factors of joint resistance of tape-to-tape joints. Since the interface resistance depends on the manufacturer and/or lot number of REBCO tapes, it is necessary to evaluate the interface resistance beforehand at temperatures and magnetic fields of the operating...
The High Temperature Superconducting (HTS) magnet system is immersed in a sub-cooled liquid nitrogen (LN2) and continuously refrigerated by a cryogenic cooling system. Especially, in case of the side-wall cooling type, the HTS magnet system is located well below the level of LN2 for thermal and electrical safety and the cryogenic gaseous nitrogen (CGN2) is filled above LN2. However, the method...
Abstract: The YBCO racetrack pancake coils were wound by dry wing followed by impregnation. Various materials such as epoxy resin, paraffin, grease and so on with and without fillers were measured to impregnate coils. The superconducting characteristics of the coils after above different materials of impregnation were tested. Due to the anisotropic of the racetrack shaped coils, the...
In high-temperature superconducting films and tapes, optical switching are complex and are determined not only by the laser pulse energy, but mainly by its duration. Thermal processes play the main role at durations from tens to hundreds of ps. To study the physical processes occurring in an HTS tape under ultrashort laser irradiation, using the Comsol Multiphysics software, a multiphysics FEM...
Recent years have seen significant development of high-temperature superconducting Bi-2212 wires and magnets in the US with record critical current density, record wire lengths and record performance model magnets. A dozen racetrack coils have been produced within the LBNL subscale accelerator magnet program using Bi-2212 Rutherford cables, including the record performance of RC6, which...
Fermilab has been developing flexible printed circuit board (flex-PCB) based quench antenna (QA) probes since 2017, and these have seen a variety of improvements and customization for different applications over the years. The flex-QA have proven to be low-noise, low-cost, non-invasive, and highly sensitive sensors for quench characterization in superconducting magnets, with potential to...
Characteristics of fly-wheel type uninterrupted power supply (FW-USP) using superconducting induction machine (SIM) is analytically studied. In the study, it is assumed that the SIM is iron-cored and composed of Cu wire stator windings and HTS rotor windings. The rotor windings are made with HTS wires embedded in an iron rotor core and connected to HTS end-rings. The whole assemble of the...
The Nb3sn was prepared successfully by two methods of mechanical alloying followed by their respective heat treatment process. The microscope morphology, crystal structure, and superconducting properties were investigated. From the results, mechanical alloying was an effective method to produce the precursor, which changed the reaction formation energy of Nb3sn and can produce Nb3sn more...
The weight loss of the organic composite materials and their matrix resins have been measured in vacuum. These are intended for use as insulating materials of fusion superconducting magnets or as structural materials used in aerospace application. Since in these applications they are used under the radiation environments, the degradation of mechanical strength will be measured together with...
Significant progress has been made recently in the U.S. Fusion community to develop a strategic plan to enable engineering design and construction of a Fusion Pilot Plant (FPP). Princeton Plasma Physics Laboratory (PPPL) is working on developing high performance HTS conductors for fusion, and partnering with the U.S. industry, we are evaluating feasibility and affordability of cable on round...
Null-flux Electro-dynamic suspension (EDS) system promises to be one of the feasible high-speed maglev systems above 600 km/h. Due to its greater current-carrying capacity, superconducting magnet can provide super-magnetomotive force that is required for null-flux EDS system and cannot be provided by electromagnets and permanent magnets. There is already a relatively mature high-speed maglev...
To get an understanding of the magnetic field distribution in a superconducting magnet, computer simulations are needed which take into account the actual geometry of the magnet and the magnetic saturation in different materials. It is a further advantage that the software efficiently tackles the large number of unknowns needed for accurate 3D simulations and also allows the coupling of...
Compared with conventional power cables, high-temperature superconducting cables (HTS) have the advantages of large current capacity, low loss, compact structure, and no electromagnetic radiation. With the continuous improvement of electricity consumption in all of the world, HTS cables are of great significance to improving the transmission capacity of power systems. Because the HTS cable has...
In order to develop high temperature superconducting (HTS) tapes with excellent low-loss characteristics, a measurement system that enables us to measure AC loss characteristics of HTS tapes with high sensitivity is indispensable. We have successfully reduced background losses, which are apparent losses obtained by a pickup coil method in case where no specimen is located inside pickup coils....
The superconducting joint is one of key technologies to evolve high temperature superconducting (HTS) conductors and their applications. Various joint techniques have been proposed in these years [1]. To evaluate developed joint efficiently, we developed a resistance evaluation system for superconducting joints [2]. The system consists of a superconductor sample with a joint, a copper coil to...
An aluminium stabilized superconducting cable is developed for the Circular Electron Positron Collider(CEPC) detector magnet. In order to measure the critical current of the prototype cable, an inductive method is developed: the cable is closed in a low resistance loop forming the secondary coil of a transformer, while the 6 Tesla background magnet serves as the primary.
The critical current...
Bilfinger NOELL GmbH is the contractor of GSI for main SIS100 magnets.
The production of the 111 SIS100 Dipoles is completed and all dipoles are delivered to GSI. We will give a summary on the production of these magnets highlighting some of the major challenges. Production workflow, individual production steps and results from quality measurements at Bilfinger Noell are presented.
In the...
As known, the cold-rolled thin Nb-Ti tapes demonstrates very strong anisotropy of pinning force regarding rolling direction and external magnetic field because of dense anisotropic grain boundary structure. This leads in particular to form of “fish-tail” feature in low-field area of magnetization loops in inclined field due to competition of self-field and small external field in media with...
Abstract:
Dynamo-type high-temperature superconducting (HTS) flux pump has been verified to be a practical method for the charge of HTS magnet, due to its simple structure and low cost. The nonlinear properties of HTS stator which is influenced by its substrate magnetism, play an important role on the charging performance of the dynamo-type HTS flux pump. Generally, there are three kinds...
Abstract: High temperature superconducting (HTS) maglev, which uses the magnetic flux pinning effect to realize the suspension and guidance, has attracted wide attention in the field of transportation due to its advantages of self-stabilizing suspension, high efficiency, and energy saving. As the connection components between the bogie and car body, and the transmission components of traction...
New generation accelerators, such as future circular collider (FCC), require superconducting dipole magnets with non-copper $J_c$ of 1500 A/mm$^2$ at 16 T, 4.2 K. Nb$_3$Sn is the only proven superconductor with large-scale industrial production. Still, present Nb$_3$Sn wires can not meet the required conditions, and improvement in the fabrication is needed. Kobe Steel Ltd. has developed...
Bi-2212/Ag round wires are promising conductor candidates for the development of high-field magnets up to 25 T. With very high upper critical magnetic field and critical current density, Cable-In-Conduit Conductor (CICC) comprised of Bi-2212/Ag superconducting wires is under designing for the central solenoid coils of the China Fusion Engineering Test Reactor (CFETER). The current degradation...
With recent progress of fabrication technology of long length and high critical current high temperature superconducting (HTS) wires, the application of HTS wires to the windings in rotational machines becomes feasible. In most current research and development of HTS rotational machines such as large scale wind turbine generators and ship propulsion motors, the HTS wires are applied only to...
GdBa2Cu3Oy (GdBCO) coated conductors is one of the most promising candidates due to its high critical temperature over 90 K and high critical current density of the order of 1 106 A/cm2 at 77 K. The presences of a-axis-oriented grains has been known to cause the worsening current characteristics, so that it is important to investigate the formation mechanism of a-axis-oriented grains. In...
Typical Cable In Conduit (CIC) typed Nb3Sn conductor applied for the fusion magnets are manufactured by twisting multiple Nb3Sn strands based on the current-carrying specification. Jc degradation by the cyclic loading in the CIC conductors was confirmed. This is caused by the Nb3Sn filament breakage by applying the huge electromagnetic force (i.e. transverse compressive load). Therefore, the...
Simply- and quickly-fabricated low-resistive joints between various high-temperature superconducting (HTS) tapes are needed for some cases in high-temperature superconducting (HTS) magnets such as nuclear magnetic resonance (NMR) magnets, nuclear fusion magnets, and so on. We have developed pressure welding with indium foil inserted between the joint surfaces at room temperature or with a...
In order to increase the diversity of people's travel mode and fill the blank of the travel speed between the aircraft (900km/h) and the high-speed train (300km/h), the high-temperature superconductor magnetic levitation train still needs to be developed. The conventional magnetic rail used for levitation mainly adopts the isometric magnets. Advanced solution uses Halbach Array, which can...
High-temperature superconducting (HTS) maglev has good application prospects due to its passive stability. There are many researches on the levitation characteristics of a single bulk HTS in applied magnetic field. However, the bulks are usually arranged in an array in practical applications. In addition, experiments proved that levitation force and guidance force of the system with two bulks...
A long-term scientific project such as the Large Hadron Collider (LHC) at CERN must undergo periodic, preventive and corrective maintenance of electronic components along their lifetime. Components that typically require replacement are the aluminium electrolytic capacitors. More than 36’000 units, rated 500 V and 4.7 mF are installed in the protection systems of the high field LHC...
The long time thermal stability and radiation resistance of micro composite wires based on Cu-Nb alloy intended for use in devices with high neutron fluxes has been studied. We have demonstrated that for a given niobium content in the alloy (6%), it is possible to keep the ultimate tensile strength higher than 375 MPa after exposed to annealing vacuum treatment at 450 °C up to 3000...
As the so-called no-insulation (NI) HTS winding technique or its variations have expanded their applications beyond laboratory magnets, technical concerns on lifecycle such as lifetime, fatigue, long-term performance variation have become an important and timely imperative issue for the actual application of an HTS magnet to real-world systems. This paper reports long-term time-varying...
Though low resistance joint is important technology for persistent current operation of HTS magnet system, superconducting joints of REBCO wires require direct epitaxial growth between REBCO surfaces that can only occur in high temperature procedure. On the other hand, at 4.2 K operation, even conventional solder spliced joints of coated conductors should have quite low joint resistance if low...
Electron-beam additive manufacturing, or electron-beam melting (EBM) is a type of additive manufacturing, or 3D printing for metal parts. The raw material (metal powder or wire) is placed under a vacuum and fused together from heating by an electron beam. This technique is distinct from selective laser sintering as the raw material fuses having completely melted.
For industries such as...
In this work, we summarize the results of an experimental campaign of inductive and transport measurements aimed at the evaluation of the electromechanical performances of a 0.85 mm diameter RRP® wire relevant for the HiLumi LHC project. SEM micrographs have been used to evaluate the sub-element diameter and Cu/non-Cu ratio, whereas the chemical composition across the sub-element sections has...
This study analyzes the output characteristics of a 100-turn non-rotational-type metal insulation (MI) coil and a no-insulation (NI) coil installed inside a 1-MW armature with external fluctuating magnetic fields. Experiments were conducted to investigate the change of state and output performance of the superconducting coils based on the fluctuating magnetic field prior to the development of...
The effect of the magnetic flux trapping in normal-phase fractal clusters on critical currents in percolative HTS composites is studied. The normal-phase clusters are united by the common trapped flux and surrounded by the filling superconducting phase. The superconducting phase fraction is above the percolation threshold so there is a superconducting percolation cluster which is carrying a...
The cross-section design of cos $\theta$ superconducting magnets is historically developed in a two-step process: initially, the coil geometry is defined on the basis of magnetic optimizations; then, the structure is designed around the coil. The first step searches for the best coil cross-section maximizing the magnetic field, margin, field quality and conductor efficiency. The latter step...
PERC is a novel experiment in the field of low energy particle physics under construction at the FRM II in Garching, Germany. The project aims to investigate angular correlations and energy spectra in the β-decay of free cold neutrons.
PERC consists of 13 superconducting solenoid coils. In a 6 m section of the 8 m long decay solenoid e- & p+ form neutron decay are accumulated. At the end of...
China Fusion Engineering Test Reactor (CFETR), a new tokamak device, is under concept design based on the experience of Experimental Advanced Superconducting Tokamak (EAST) and ITER. Research and development of TF coil for CFETR is carried out by ASIPP. TF coil is winding by Cable in-Conduit Conductor (CICC). Main manufacturing process of CICC includes welding of jacket, draw lead, winding and...
The performance of accelerator magnets is strongly relying on the dielectric strength given by the electrical and mechanical robustness of the insulation system. This is in particular relevant for the current development of high field superconducting Nb3Sn magnets with their insulation system made from fibre reinforced resin. During the assembly and operation, this insulation system is exposed...
The new Nb3Sn superconducting magnet system for a 45 GHz electron cyclotron resonance (ECR) ion source is under developing in the Institute of Modern Physics (IMP). The sextupole coil, which is wound by a single Nb3Sn wire, is indeed a great technical challenge. Because of the complicated technology process and the stress sensitivity of the full-length Nb3Sn sextupole coil, a sextupole...
Nb3Al superconducting wires have high critical current and low strain sensitivity of the superconducting properties. Therefore, many Nb3Al wires were developed for accelerator or fusion magnets. In this study, critical current and mechanical properties of various Nb3Al wires were investigated. Some kinds of rapid heating, quenching and transformation (RHQT) processed Nb3Al wires were prepared....
The Fourth-generation ECR (FECR) ion source Nb3Sn Superconducting Magnet is being developed by Institute of modern physics, Chinese Academy of Sciences. In order to reduce the risk of development, a representative prototype is designed. The FECR prototype consists of two Nb3Sn solenoid coils and six Nb3Sn sextupole coils, This paper reports on the assembly process and cool-down to cryogenic...
Hf addition together with Ta to the Nb cores results in significant refinement of the Nb3Sn grain morphology, leading to large enhancement of flux pinning characteristics. That is why it attracts much interest in the field of Nb3Sn wire development. This effect has been confirmed so far for the internal tin Nb3Sn wires. However, this effect should be naturally expected also for the bronze...
High-temperature superconducting (HTS) tapes in a superconducting cable are twisted and stacked as multi-layer. The superconducting tapes are exposed to a combined magnetic field of the circumferential magnetic field created by the inner layers and the longitudinal magnetic field created by the twisted outer layers. The AC loss in superconducting tapes under HTS cable electromagnetic...
Improvement in the production technology of a Conductor on a rounded core (CORC) cable allows it to reach high engineering current densities and therefore becomes suitable for high fields magnets like MRI or acceleration magnets. Due to high packed tapes within the cable being magnetically coupled, this results in an increase in the magnetization loss, the load on the cryogenic system and...
Columnar defects (CDs) are useful pinning centers (PCs) not only to improve the absolute value of critical current density Jc in a magnetic field (B) but also to modify the anisotropy of Jc of high Tc superconductors: the modification of Jc by installing CDs in a controlled manner can be one of key technologies for superconducting magnet applications using REBa2Cu3Oy coated conductors....
The high-temperature superconducting (HTS) maglev system has tremendous possibilities for future high-speed transportation owing to its salient superiorities of self-stable. However, previous study had indicated that the relatively low damping of HTS maglev system may cause the undesired large-amplitude nonlinear vibration in system. To solve that, electromagnetic shunt damper (EMSD), which...
The superconducting magnets (SCMs) and figure-eight coils (FECs) are core components for the null-flux superconducting electrodynamic suspension (NFSEDS). In this paper, the multi-objective optimization design of NFSEDS is investigated to decrease the size of SCM and FEC based on Non-dominated Sorting Genetic Algorithm-II (NSGA-II). Twelve design variables are selected including the size of...
An advanced hybrid numerical method for the solution of nonlinear magnetostatic problems in superconducting accelerator magnets is proposed. The methodology is implemented in PITHIA-EM software and couples the Fragile Points Method (FPM) with the Boundary Element Method (BEM). The FPM is a Galerkin-type meshless method, based on a Discontinuous Galerkin weak form where simple, local, and...
Nuclear fusion, regarded as a promising and infinite energy resource, is under rapid development. Associated with multiple essential advantages, such as carbon free, low land use, unlimited fuel and very low manageable waste, a number of high quality and multinational fusion projects are under construction. Tokamak, as an essential device for plasma confinement, is a key focus investigated...
The strain sensitivity of Nb3Sn is considered one of the main challenges that has to be solved to use the full potential of this conductor in particle accelerator magnets application. In these applications, significant forces are applied to the superconducting coils both during the assembly and cooldown to cryogenic temperatures, and then during powering. The composite coil reacts...
We have been studying the No-insulation coil (NI coil) for applications to medical cyclotrons for cancer therapy and high-magnetic-field whole-body MRIs. Since the layers in NI coil winding are not electrically insulated from each other, the current can be bypassing the adjacent layers when a local defect or normal transition occurs in the coil. Therefore, NI coil is expected to realize both...
We are developing large diameter (m-class) no-insulation (NI) REBCO coil systems for applications such as cyclotrons for cancer treatment and high-magnetic-field whole-body MRI. NI coil technology is expected achieving both high thermal stability and high current density, which are essentially tradeoff relationships. Conventionally, superconducting coils have been required to quickly dissipate...
We have been developing the No-insulation (NI) REBCO coil for applications to medical cyclotrons for cancer therapy and high-magnetic-field whole-body MRIs. NI-REBCO pancake coil is expected that can realize both high current density and high thermal stability, which are essentially trade-off relationship. Since in an NI coil, electrical insulation is eliminated, the operating current can...
We are developing a high-Tc superconducting (HTS) air-core compact cyclotron, named Skeleton Cyclotron, that can accelerate various particles and variable energy for radio isotope (RI) production. The coil system of Skeleton Cyclotron consists of circular and noncircular REBCO coils for high magnetic field strength and high current density. However, the higher operating current density leads...
In recent years, advanced cancer treatment technologies have been required to deal with cancer patients with various disease sites and stages. Especially, targeted alpha-particle therapy is expected. In targeted alpha-particle therapy, a targeted drug labelled by alpha-emitting-RI is administered in a cancer patient. Therefore, nuclide production facilities are required, and alpha-emitting-RI...
The Center Solenoid Model Coil (CSMC) is a pre-research project of CFETR, and its task is to design and manufacture the CS superconducting model coil to gain wider experience in solving the related technical problems existing in design and construction of CFETR CS coils. The expected achievement is to charge the CSMC up to the operation current of 47.65 kA and the maximum magnetic field to 12...
More attention is focused on high temperature superconducting (HTS) machines due to lighter weight, smaller size, higher power density and torque than conventional counterparts. An axial-type synchronous motor with Gd-123 bulk as field poles has been manufactured and tested successfully in Tokyo University of Marine Science and Technology. The rated output power of the HTS motor is 30 kW at a...
Over the past decade High Temperature Superconductors (HTS) have gained interest for use in large scale coils for fusion applications. It is necessary to use a cable consisting of multiple parallel tapes in order to reduce the coil's inductance and to mitigate point defects. In many fusion and also non-fusion cable concepts the tapes are often transposed to reduce AC-losses. However, it has...
The enhancement of the acceleration performance of a superconducting linear acceleration (SLA) system to inject the pellet container to supply fuel to the fusion reactor has been investigated numerically. To this end, a numerical code used in the finite element method has been developed for analyzing the shielding current density in a high-temperature superconducting film. In addition, the...
High-speed forming can greatly improve the forming performance of lightweight sheet and tube components, and has broad application prospects in aerospace and automobile manufacturing. Electro-hydraulic forming (EHF) and electromagnetic forming (EMF) are two common high-speed forming processes. EHF utilizes the underwater discharge to produce a shock pressure as the driving force, while EMF...
The high temperature superconducting (HTS) quasi-isotropic conductor with high current capacity and quasi-isotropic performance is expected to have a wide application. AC loss is one of the major obstacles. This paper aims to study the AC loss of the quasi-isotropic conductor stacked by the second generation (2G) HTS tapes and copper tapes at 4.2 K. In order to fully understand AC loss...
HTS magnets with magnetomotive force >360 kA and off-power operation time longer than 1 hour have been achieved for a prototype Maglev train. Off-power operation means no power source, no cryocooler, no vacuum pump and no more cryogen supply in the vehicle, like permanent magnets. Such operation mode was realized based on the following techniques: (1) persistent current mode (PCM) operation of...
The traditional endoscope mainly relies on the operation of the operator. The intestinal wall is often deformed and bent when pushed the operator pushed endoscope in, which increases the probability of damage to the intestinal tissue. Here, a flexible endoscope (FE) is developed that overcomes the shortcomings of traditional endoscopes. In order to improve maneuverability, a permanent magnet...
Our research group has developed a High Temperature Superconducting Induction/Synchronous Motor (HTS-ISM) for next-generation transportation equipment. It was clarified based on the experimental and the analytical studies that the fabricated HTS-ISM possesses not only the excellent steady performances such as high torque density, high efficiency, but also the novel transient characteristics...
This solenoid will be used in new spectroscopy method in less researched THz range. The method is founded on using of a free electron laser with high spectral power radiation which can be smoothly tuned in desirable range of spectrum. The objects of research of this method are fast processes in physics, chemical and biological reactions. Uniform magnetic field of ~ 6 T value in the research...
A joint-less winding method uses second-generation (2G) high-temperature superconductors (HTS) to make an HTS magnet for persistent current mode operation without superconducting joint. Starting with simple double pancake HTS coil wound, we have tried to make and test various types of the joint-less HTS coils. Most recently, a prototype of a concentrically arranged joint-less magnet was made...
A phasing magnet has been developed at National Synchrotron Light Source II (NSLS-II) for the Coherent Soft X-ray Scattering (CSX) beamline. The phasing magnet will be located at the center of the straight section in between two identical and independent variably polarized APPLE-II devices. Based on Permanent Magnet technology, the phasing magnet has been designed to achieve the required...
High temperature superconductor (HTS) technology has been widely studied for various superconducting devices due to the capability of high magnetic field generation and its relatively strong strain resistance. Fusion magnet engineers also have made efforts to employ the HTS technology to their magnets, especially focused on the development of HTS cable-in-conduit conductor (CICC) such as...
High field superconducting magnets sustain large Lorenz force during operation. The superconductors for high field applications like Nb3Sn is strain sensitive, therefore it is essential to measure the strain level in superconducting coils during operation. Compared with traditional approach with resistance stain gauges, Fiber Bragg Grating Sensors (FBG) has significant advantages in high field...
The Center Solenoid Model Coil (CSMC) is a pre-research project of CFETR, and its task is to design and manufacture the CS superconducting model coil to gain wider experience in solving the related technical problems existing in design and construction of CFETR CS coils. The expected achievement is to charge the CSMC up to the operation current of 47.65 kA and the maximum magnetic field to 12...
EDIPO 2 (the upgraded EDIPO test facility) will provide a unique testbed for superconducting cables for fusion magnets, accelerators, and other applications. Compared to the previous magnet assembly, the magnetic field is enhanced from 12.35 T to 15 T, the aperture is enlarged from 90×141 mm2 to 144×144 mm2 and the uniform field length is increased from 680 mm to 1000 mm...
ReBCO-based CORC® superconducting cables [1] can enable compact fusion reactors and high-field accelerator magnets. However, additional research is required to develop sensitive and robust quench detection methods. One potential technique utilizes Hall probe arrays in CORC® cable terminations to monitor inter-tape current redistribution [2] as a proxy for quench detection. In short-sample...
Nested combined orbit correctors are needed for the upgrade of LHC. They are developed at CIEMAT, in collaboration with CERN in the framework of HL-LHC project. There are two types of magnets, so-called MCBXFA and MCBXFB, with different lengths (2.5 and 1.5 m, respectively), but sharing the same cross section. Coils of both magnets are wound with the same Rutherford-type NbTi cable, composed...
Institute of Modern Physics is developing the Fourth-generation of Electron Cyclotron Resonance source, also known as FECR. In order to fulfill the requirements of higher beam intensity and quality, the FECR needs a Nb3Sn superconducting magnet with high performance and complex structure. Therefore, a half-scale prototype is produced for the technical research, it was wound by a 1.3mm diameter...
We fabricated a conduction-cooled 3 T REBCO MRI magnet equipped with electrically conductive epoxy resin. The magnet is composed of 100 single pancakes and the total inductance is 91 H. When the operating current is 145 A, the central magnetic field is 3 T and the stored energy is 1 MJ. A quench protection test was carried out by raising the coil temperature using the heater. After the coil...
In industries, there are many issues against the implementation of conventional heating furnaces. First, the government recently executed an environmental protection policy that requires industries to use better technologies against low efficiency and CO2 emissions, etc. Second, industries use old and inefficient technologies for heating metals with large capacity and low efficiency. Also, the...
Aluminum alloy rings are the key component to realize the lightweight and improve the mechanical properties of aerospace vehicles and devices. However, the residual stress is inevitably introduced by uneven heating and mechanical load having a negative effect on the dimensional accuracy and performance of the rings. Therefore, the elimination of residual stress is of great significance to...
We report the current state of research and development to realize a new design theory of High Temperature Superconducting (HTS) armatures that achieve both robustness and low-loss characteristics. In order to realize it, the self-organizing design method, which is the first-principles design method [1], and the Face-to-Face Double Stacked (FFDS) conductor technique [2] are effectively...
Several ultra-high magnetic field (>20 T) REBCO magnets are under development for fundamental research or practical applications. A few quench protection techniques, such as a no-insulation winding technique and a temperature rise technique by heaters, were proposed to protect REBCO magnets from thermal runaway and burning-out. Meanwhile, it was reported that REBCO tapes were plastically...
Transcranial magnetic stimulation has important applications in clinical diagnosis, clinical treatment and scientific research. In transcranial magnetic stimulation, the geometric configuration of the coil is particularly important, which determines the stimulation intensity and focalization. To improve these two indicators of transcranial magnetic stimulation, a novel coil is proposed in this...
Magnetic drug delivery system (MDDS) can deliver the magnetic drug to a specific area and reduce the side effect on healthy tissues. To improve its delivery efficacy, the high magnetic field strength and gradient are required. In order to understand the motion of the magnetic drugs under high magnetic field, this study established a multi-physics simulation model (including: magnetic force,...
We are studding the superconducting joint between multi-filamentary Bi2223 tapes with incongruent melting (JIM) method, to develop a high-field 1.3 GHz-NMR in Japan. We obtained critical currents of 12 A at 77 K and 177A at 4 K for the reinforced HT-NX type wire in early stage of the study [1], and a high critical current above 50 A at 77 K was obtained in non-reinforced H type wire [2]. For...
The Mu2e field mapping system is designed to produce high accuracy field maps of the detector solenoid used in the experiment. The data acquisition system is mobile and uses a self-propelled mapper with rotating arms equipped with 3D Hall probes. The measurements require not only accurate readouts of magnetic field, but also accurate location of all the Hall probes when taking data. The...
In ITER magnet system, there are feeders for toroidal field (TF) coils, poloidal field (PF) coils, central solenoid (CS) modules, correction coils (CC), magnet structure cooling and monitoring instrumentation. Main busbar is used for TF, PF and CS feeders and corrector busbar for CC feeders. Main Busbar (MB) operated up to 68 kA with peak field of 3.6 T is used for TF, PF and CS feeders....
Sirius is a 3 GeV 4th generation synchrotron light source located in Campinas, Brazil. Sirius first delta undulator is currently being built. It is a 1.2m long permanent magnet structure with 21 periods with a lengh of 52.5mm and 13.6mm gap. This paper provides an overview of the current status of the delta undulator regarding development, construction, measurements and correction of the...
Superconducting motors have been studied for electric vehicles, airplanes, and so on in the world. Therefore, superconducting motors become lightweight and have a high-power density. Since REBCO superconducting tapes have tape-shapes, motors with racetrack coils as armature windings have been studied. However, racetrack coils are inferiority in the respect of increasing interlinkage flux to...
There are already a wide variety of medical mixers used in the pharmaceutical manufacturing process, and they have contributed greatly to many people suffering from diseases. However, most of the rotating machine used in current medical mixers adopt the mechanical bearing system, and dust is generated by friction with the rotating shaft. In addition, the contact rotating system has...
We have previously demonstrated proof-of-concept no-insulation style coils wound with a heavily filled conductive epoxy resin system. This epoxy resin system appears to eliminate REBCO delamination, and also allows for tuneable contact resistance between turns. The coils we have reported to date are small coils with an ID of approximately 25 mm and an OD of approximately 50 mm with an...
In recent years, magnesium diboride (MgB2) wire has become a promising candidate for the development of superconducting magnetic resonance imaging (MRI) magnets because of its critical temperature (39 K), which allows magnets to be operated without using liquid helium. Extensive research using unreacted MgB2 wire has enabled MgB2 MRI magnets to be operated in persistent current mode (PCM). We...
Bilfinger NOELL GmbH is active in the field of superconducting magnets for particle traps. We report on two types of traps: a magnet for a neutron trap and several magnets for antiproton traps.
Bilfinger NOELL has developed, manufactured and delivered a large volume magnetic storage device for ultra-cold neutrons to Technical University of Munich in June 2020. The magnet of PENeLOPE...
We have fabricated Ce and La co-doped Gd123 thin films on LaAlO3 single crystal substrates by the fluorine free metal organic deposition method (FF-MOD). From our previous study, it is confirmed that Ce doping is effective in introducing artificial pinning centers (APCs) into GdBa2Cu3Oy coated conductors. In addition, La doping promotes...
We performed characterization of superconducting properties of production 2G HTS wires based on YBCO with Y2O3 nanoparticles, which were developed recently specifically for application in high magnetic field [1], including magnets for compact fusion reactors and particle accelerators. We measured magnetization curves using vibrating sample magnetometer (VSM) in the Quantum Design PPMS (in the...
Since superconducting technology has advantages of high efficiency, large capacity, and eco-friendliness, HVDC superconducting power devices such as superconducting cable, transformers, fault current limiters, and magnetic energy storage are being extensively studied. The creepage distance of solid insulator is very important for the reliable and economical insulation design of the HVDC...
Bearingless switched reluctance motor (BSRM) has the advantages of simple structure, no winding and permanent magnet on rotor, low cost, good robustness, strong fault tolerance and strong environmental adaptability. Therefore, the BSRM has broad application prospects in the field of high-speed direct drive system, such as aerospace, high-speed flywheel and turbo molecular pump.
The levitation...
The purpose of applying electromagnetic stirring was to change the flow field of molten steel in crystallizer during the solidification of casting blank, ultimately improving the quality of the steel. The strong static magnetic field was generated by the high-temperature superconducting magnets and rotated outside the crystallizer. The molten steel cut the magnetic line in the crystallizer to...
The high-temperature superconducting induction heating technology could widely use in industrial production such as penetrating heating, quenching heating, welding and melting of steel. The steel uses the strong static magnetic field generated by the superconducting magnets of the high-temperature superconducting induction heating device. The steel rotate in the air gap and cut magnetic lines...
Superconducting racetrack shaped magnet has been fabricated successfully aiming at its application to superconducting undulator. The magnet was wound with NbTi superconducting wires by a method of dry winding followed by the vaccum pressure impregnation. First the single coil was fabricated and the critical current was tested in liquid helium. The critical currents of the six coils tested were...
A new PrFeB cryogenic permanent magnet undulator (CPMU) prototype with 12mm period length is being constructed for High Energy Photon Source (HEPS) at IHEP. HEPS is a new 6 GeV synchrotron radiation light source. Insertion devices play a significant role in achieving the high performance of the photons. The magnetic field performance of the CPMU must be measured in the vacuum chamber and...
For the High Luminosity upgrade of the Large Hadron Collider (HL-LHC), CERN has procured about 20 tons of high critical current density Jc (>1200 A/mm2 at 15 T, 4.22 K) and high RRR (>150) wire from Bruker-EAS and Bruker-OST (1135 km of the 0.7 mm 108/127 RRP wire; 590 km of the 0.85 mm 192 bundle-barrier PIT wire and; 2180 km of the 0.85 mm 108/127 RRP wire). This conductor has been used for...
The storage ring of Hefei Advanced Light Facility(HALF) will employ high-gradient quadrupoles for the sake of diffraction limit, the typical gradient values of them arrive at 60-80 T/m, the saturation on the pole tip is very serious. Moreover, the gap between two adjacent poles should have a certain interval to accommodate light box, which is equal to reduce the pole width. All the cases...
The demand for high power density motors for electric propulsion aircraft demands conductors capable of withstanding high frequencies (i.e., 300-1kHz), but also capable of high current density. This is because motor power increases with B, J, and w. Superconductors are attractive because of their high J which can lead also to high B, but they are presently limited to f < 300 Hz. One...
Abstract: A special necking morphology was observed on Cu-Nb composites after the thermal compression. During the compression process under the heating temperature above 700℃, the nanofibers recrystallized rapidly, and the properties of Cu-Nb composites rapidly attenuated in the dynamic instabilty, and it was difficult to observe the rheological area. During the compression process below 700℃,...
The no-insulation HTS coils can be excited above their critical current without burning out. The saturation of the magnetic field can be observed in the overcurrent excitation test, however, as the power supply further increases, there is still a risk of burning out of the NI HTS coil. This report uses a distributed circuit model validated by overcurrent experiments to study the overcurrent...
Tokamak is a feasible device to keep the fusion reaction by magnetic confinement method. The high DC current is loaded on toroidal field (TF) magnets to generate high field for plasma confinement. However, this load may also bring heat loss for normal conductor and the risk of melting. High temperature superconductor has great potential for TF magnets due to its zero resistance and high...
Based on the designed field current of an high temperature superconducting (HTS) synchronous motor and the cooling temperature at 30K in our laboratory,this article introduces the structure and fabrication of a novel cryostat suitable for a linear-motor type flux pump used on an synchronous motor, and reports the charging test of the HTS no-insulated (NI) double racetrack coil used in the...
Due to excellent thermal stability and high-power density in steady state, no-insulation (NI) winding technology is widely used in the application of superconducting magnets. However, current ripple and background magnetic field fluctuations caused by relative devices result repetitive turn-to-turn current of the NI interpolated coil, which will impose a great impact on the thermal stability...
A 240 MeV proton cyclotron is under-development in Hefei for proton medical application. Two double-split HTS superconducting coils are designed to generate max. 5 T magnetic fields which are used to confine the proton beam revolving around the median plane. In the past experience, low temperature superconducting coils are classic design, but people have to face lower operating temperature and...
Thermal effect on the magnet materials and magnetic structure plays an important role in the performance of the insertion devices such as the in-vacuum undulator. By cooling the magnetic structure to low temperature to achieve higher peak magnetic field and higher resistance to demagnetization, cryogenic permanent magnet undulator (CPMU) developed from the conventional in-vacuum undulator has...
Electromagnetic forming (EMF) is an important application of pulsed magnetic field technology, which uses a pulsed magnetic field to induce a Lorentz force on a metal workpiece, thus shaping the workpiece into desired geometry. Compared to conventional forming processes, EMF can significantly enhance the formability of materials, making it a promising option for high strength metal alloys...
Electromagnetic forming (EMF) is a metal forming process based on pulsed magnetic field. Instead of using mechanical force as in conventional forming process, EMF shall reshape metal workpiece by using a pulsed Lorentz force which is induced by a pulsed magnetic field. By adjusting the geometry configuration of the field generator (namely, coil), the Lorentz force with manifold spatial...
High-temperature superconducting (HTS) cables are rapidly developed for their increased transmission capacity and reduced power transmission losses, and PPLP with excellent low-temperature dielectric and mechanical characteristics is used as insulation materials for HTS AC cables. However, unlike AC, since the direction of the electric field does not change in the DC environment, the space...
The next generation NMR spectrometer operated at 1.3 GHz (30.5 T) is currently being developed [1]. The superconducting magnet in this NMR consists of low temperature superconducting (LTS) coils using Nb-Ti and Nb3Sn, and high temperature superconducting (HTS) coils using Bi2223 and RE123, which are connected in series. Superconducting joints between Nb-Ti and Bi2223 are preferable to realize...
In the industry for Nb3Sn conductors at the moment, it is considered that 16 mass% is a limit of the tin content for the bronze process as well as a limit of the critical current density (Jc). Because the mechanical performance of the bronze dramatically changes from ductile to brittle with increasing the thin concentration over 16 mass%. Therefore, the internal tin process using pure tin...
Bi-2212 conductor is now a serious candidate for HEP, NMR, and other ultra-high field magnet applications since our demonstration that 50 bar over-pressure heat treatment (OPHT) is reliable and predictable for many coil reactions. As more magnet designs are generated, predictable and consistent critical current density ($J_{\text{c}}$) values are important too. In fact there are still...
EU DEMOnstration reactor (DEMO) aims towards demonstrating the feasibility of commercial fusion power plant. Various activities are in progress as part of EUROfusion’s framework for the design of DEMO. As part of the mechanical assessment activities, various Finite Element (FE) analysis on these complex systems are performed. Due to the large dimensions of the magnets, a multiscale approach is...
A variable resistance thin dielectric insulation coating for REBCO tape HTS coils has been developed. This new type of insulation system switches between fully insulating and conducting, after an increase in inter turn voltage. Non-Insulated (NI), fully soldered, HTS coils have proven to be very reliable; NI coils are achieving high magnetic fields above 25 Tesla and are almost impossible to...
To prevent an unintended shutdown of the high-temperature superconducting devices (HTS), the monitoring and diagnosing system to quantitatively estimate the degradation of superconducting properties before the normal transitions occur has been proposed. Only the active power component of the Poynting vector measured around the coil conducting AC transporting current is observed in the system....
Elevated bridge is applied widely in maglev railway systems for high-speed ground passenger transportation. But the vibration of vehicle and bridge is essentially coupled with each other and there is a strong problem of vehicle-bridge coupled vibration. Therefore, it is necessary to investigate the vertical dynamic characteristics of superconducting electrodynamic suspension (EDS) train...
Starting with Gamma sources before moving to Xrays, Radiation therapy also proposes protons or heavier ions like carbon to treat cancer tumours with unrivalled accuracy. Today, radiation Therapy is a proven cancer treatment modality from which several tens of thousands patients benefit each year. But being a proven treatment modality does not mean it is not evolving.
In this plenary, we will...
We present the integration and initial test of the world’s first superconducting magnet system for Magnetic Density Separation, from coil winding to cryostat assembly as well as first cool-down and energizing. Magnetic Density Separation is a relatively new separation technology that allows the simultaneous sorting of multiple non-magnetic materials based on their mass density by combining a...
Fusion power plants offer the prospect of a new sustainable source of energy for future generations. The design and R&D of future reactors is expected to largely benefit from the experience gained in the design, construction and operation of ITER. However, deploying reliable fusion power plants, requires to overcome the design challenges and to address the remaining readiness gaps. Europe is...
High-temperature superconducting REBCO tapes are expected to be applied to next-generation magnets for their high critical current density. One of their problems in the magnet application is the magnetic field instability caused by the decay of magnetization due to the shielding current caused by the tape shape. Therefore, it is important to evaluate the magnetization relaxation of REBCO tapes...
The Chinese Fusion Engineering Testing Reactor (CFETR) is a DEMO design to bridging the gap between ITER and the first commercial fusion power plant. Toroidal field (TF) magnet system is one of the most challenge for CFETR project. The operating current of the TF magnet is 95.6 kA. The major radius and minor radius of CFETR is designed as 7.2 m and 2.2 m, respectively. To reduce the...
We have started to develop a magnetic refrigeration system for hydrogen liquefaction. This system has a superconducting magnet, in which an active magnetic regenerative (AMR) bed moves inside. During steady-state operation, there is a possibility that the superconducting magnet is conduction cooled by the cold of liquefied hydrogen. However, since it is in the development stage, the magnet is...
Non-insulated (NI) coils in superconducting REBCO high-field magnets provide electro-thermal stability. However, current transfer between turns through the metal causes transient currents and magnetic fields, increasing the AC loss and requiring longer times to charge the magnet. Therefore, magnet design and optimization requires numerical modeling. Although 3D modeling provides the full...
In this study, we focused on the layered winding concept, in which the conductor can be optimized for each layer by grading, and succeeded in the significant improvement of the conventional rectangular conductor winding concept. The radial plate (RP) system is the main proposal for the toroidal field (TF) coil of Japan's DEMO (JA DEMO), because of its performance in ITER. However, the RP...
High-temperature superconducting (HTS) composites are being considered for use in high-field magnets for future particle accelerators, as they allow the development of very high field dipoles and quadrupoles. As part of the US Magnet Development Program, LBNL is developing Bi2212- and REBCO-based insert magnets towards 20 T hybrid dipole magnets. The field quality of the magnets is important...
High-temperature superconducting (HTS) coils and magnet systems are used in various applications today. Despite the great advantages they offer over conventional systems, their commercial success is yet pending. A major obstacle is a high price due to the cost of the HTS tape and the development effort needed to meet very specific requirements.
In various projects, we have developed...
Superconducting magnets are capable of producing exceptionally stable magnetic fields when operating in “persistent current” mode. In this approach, a superconducting switch disconnects the power source from the magnet circuit, allowing the magnet current to flow in a closed superconducting loop free of power supply noise. We present the design, fabrication, and test of a 1.9 T iron-dominated,...
Tokamak Energy Ltd is a UK company developing spherical tokamaks incorporating HTS magnets in the pursuit of fusion energy production.
A series of demonstration projects has been conducted on a rapid development cycle to generate stable and robust magnet structures, experimental test capabilities, and simulation tools sufficient for the design and construction of a major HTS magnet system...
In agreement with CERN the LASA laboratory of INFN (National Institute for Nuclear Physics) of Milan has carried out the industrial development of a novel type of magnet, for the High Order (HO) correctors of the High Luminosity - LHC (HL-LHC) project. These corrector magnets are based on a superferric design and will be installed in the new HL-LHC insertion regions for the ATLAS and CMS...
Most of the existing AC loss experiments and simulations of High Temperature Superconductors Coils deal with low currents of less than 100 A, which does not provide sufficient data or analysis for the HTS coils with higher current at 500 A to 800 A. If the AC loss is considerably larger, it will result in high heat dissipation into the HTS coils, and so as to elevate the coil temperature and...
The Super Separator Spectrometer (S3) aims to study the limits of the nuclear existence [1][2].
In order to achieve large momentum as well as charge-state acceptance for S3 layout, a high-gradient field magnet technology that generates a pure normal multipole field has been designed. This magnet is designed according to the current sheet approach. For a better overall quality field produced...
Magnetic field and current variations are responsible for AC losses in superconductive magnets. These losses may induce an increase of temperature within the material and negatively affect the performance of the magnet.
Developed at CEA, the new fully analytical model named COLISEUM (COupling Losses analytIcal Stages cablEs Unified Model) aims at predicting the coupling losses at various...
The self-field critical current Ic of 2G high temperature superconducting (HTS) tape can be reduced by applied dc magnetic field. This property can be used in the development of HTS switching elements through so-called Jc(B) switching. The design of a dc magnetic field switch is reported with both single and bifilar configurations. Dc magnetic field is applied by an iron-core field coil with...
The no-insulation (NI) high temperature superconductor (HTS) toroidal field (TF) coil or its variations have been regarded as a potential option for a compact, high magnetic field tokamak due to compactness in size and robustness in operational reliability. However, its real application still faces multiple challenges, e.g., we have limited experience in design, construction, and operation of...
Superconducting magnets have been attracting research interest due to their numerous applications, which include accelerator magnets, fusion magnets and superconducting trains. However, as the coils driving the magnets require large currents, the losses in the current leads supplying the coils can be problematic. Power semiconductor devices have shown improved performance at cryogenic...
During its nominal operation, strong current variation, more than 10 kA per second, can be imposed on the KSTAR PF (Poloidal Field) magnet system. Due to AC loss, transient massive backward flow can occur, especially at the cryogen inlets of each magnet. To protect cryogen circulator, several valves are activated to adjust or lower pressure below the circulator’s operation limit. In this work,...
Over 30 years ITER has been through many design iterations and multiple novel solutions for the magnets have been tried, in some cases being carried through to successful manufacturing and in other cases being abandoned. Now that ITER operation is approaching, the fusion community is considering possible next steps, to a power producing fusion plant. If we consider the long road ITER has...
Superconducting accelerator magnets, due to their high aspect ratio and field configurations, have some unique design and fabrication issues, particularly for higher magnetic field configurations. After more than a half century, the accelerator magnet community is, for the first time, now on the verge of installing magnets based on Nb3Sn in the Large Hadron Collider at CERN. Much experience...
The upgrade of the LHC to increase luminosity (High Luminosity LHC) requires the construction of six different types of accelerator magnets based on LTS technology. Besides the quadrupoles in Nb3Sn, with peak field of 11.5 T, we have two different dipoles in the 4.5-5.6 T range based on Nb-Ti, and three types of correctors. All magnets are characterized by wide apertures (150 mm), posing...
The National High Magnetic Field Laboratory headquartered at Florida State University in Tallahassee, Florida, USA designs, builds, and operates a variety of ultra-high field magnets including superconducting magnets providing up to 32 T, dc resistive magnets providing up to 41.5 T, resistive/superconducting hybrid magnets up to 45.1 T, and pulsed magnets up to 100 T. Some of the "lessons...
Firstly reported by MIT in 2010, the no-insulation (NI) high temperature superconductor (HTS) winding technique introduced a new philosophy of HTS magnet protection: “current sharing” with adjacent turns upon a quench. The protection mechanism of the NI HTS technique was later explained by RIKEN: the multi-turn-to-single-turn transition. To mitigate the charging delay, a major drawback of NI...
Quality Assurance (and the derived quality controls) define the Nuclear Quality Approach in ITER. The higher the impact of manufacturing and assembly errors, then the more rigorous the QA regime, leading eventually to Safety Specific controls such as the appointment of an Authorised Notified Body ANB, by the Safety Regulator. Requirements come from regulatory and safety surveillance, quality...
MuSEUM experiment is in progress at J-PARC to measure the muonium hyperfine structure with a sensitivity as low as a few ppb. Muon g-2/EDM experiment is also planned in J-PARC to measure muon’s anomalous magnetic moment and electric dipole moment with an accuracy below 0.1 ppm. Both experiments require high homogeneous magnetic field below 0.2 ppm pp(peak-to-peak). Commercial MRI magnets...
Low emittance machines require lattices with many magnets of short length. Furthermore, successful lattices require strong gradients with strong dipole fields. These lattices are popular today, as MAX IV has demonstrated that a diffraction limited synchrotron light source can be based on such a lattice.
This paper gives an overview of the various magnets used by the different diffraction...
In this paper, we present results, analytical and experimental, of two dimensionally identical 1.5 T NbTi coils with a 2-T peak field, operated in the 4.2-6 K range, one impregnated with paraffin and the other solid nitrogen (SN2). In the paraffin coil, the paraffin prevents conductor motion and the coil operates stably in the temperature range. In the SN2 coil, although not as strong as...
Bulky metallic structures are needed in the toroidal field (TF) superconducting magnets for fusion applications to withstand the large Lorentz forces acting on the winding. The pulsed coil operation during the plasma scenario and the fast current discharge or a plasma disruption in off-normal operating conditions cause magnetic field variations, inducing eddy currents in the TF structures. The...
MgB2 in bulk form shows great promise as a trapped field magnet (TFM) as an alternative to bulk (RE)BaCuO materials to replace permanent magnets in applications such as desktop high-field magnet systems and rotating machines. In addition to being inexpensive and lightweight, they exhibit a number of additional advantages: a long coherence length, smaller anisotropy, strongly-linked...
This paper proposes a dual-stator high-temperature-superconducting modular linear vernier motor (DS-HTS-MLVM), suitable for long stroke applications. The dual stators are two pure slotted-cores and staggered by half the stator pole-pitch. The mover adopts a modular structure, installed with HTS excitation windings and copper armature windings. The cryostats for HTS windings also adopt a...
For generating diversified magnetic field waveforms, a flexible control system of Pulsed High Magnetic Field Facility (PHMFF) has been developed at Wuhan national pulsed High Magnetic Field Centre (WHMFC). Firstly, in order to describe various magnetic field systems, a general physical model composed of energy storage modules, load unit, transport circuits, and other auxiliary units is...
Cryogenic system plays a vital role in the development of magnet technology. Especially for superconducting magnet，it would be in more widespread use now if it were not for the problems associated with the cryocoolers or cryostats required to cool down those superconducting devices or facilities.
For a variety of high-Tc superconducting magnet applications such as energy storage, generators...
A 1.15 GHz nuclear magnetic resonance (NMR) spectrometer magnet has been under study at the Institute of Electrical Engineering of the Chinese Academy of Sciences. This NMR magnet requires spatial field homogeneity to reach 4 per million (ppm) in a sphere with a diameter of 40 millimeters. To achieve such a high magnetic field quality, each double pancake was wound with Bi-2223 tapes to reduce...
The persistent current switch (PCS) is essential for magnetic resonance imaging magnet (MRI) magnet which works in closed-loop mode. In this paper, the design of NbTi/CuNi thermally triggered PCS is presented. Furthermore, quench test and switching time test have been given at 4.2-K temperature and 0-3 T magnetic field.
Power electronic devices are typically utilized to provide quench protection for the superconducting magnets. Integrating quench protection devices in the Dewar can make the system more compact. The cryogenic characteristics of the power electronic device are therefore necessary to be studied in order to ensure that it can work properly under the low-temperature condition. The characteristics...
A major focus of Nb3Sn high field accelerator magnets for HEP is on significantly reducing or eliminating their training by understanding the underlying physics mechanisms. We have been are investigating whether mixing organic olefin-based thermosetting dicyclopentadiene (DCP) resin, commercially available as TELENE○R by RIMTEC Corporation in Japan, with high heat capacity ceramic powders,...
A REBCO bulk magnet can make a higher magnetic field than the existing permanent magnets and electromagnets. Recently, various applications of the bulk magnet, such as a compact NMR/MRI system, a magnetic separation system, a generator for a large-scale wind turbine, an electric motor for a ship propulsion system, an aircraft electric population system, and so on, have been developed and...
Based on finite element method (FEM) and difference method, a simulation method for the quench behavior of superconductors is introduced in this paper. With this method, the heat conduction equation of a superconductor under a thermal disturbance can be solved simply and visually. The stability of an REBCO high temperature superconducting tape under adiabaticapproximation is simulated, and ...
A 4.8-m-long cryostat has been developed to cool a pair of 1.9-m-long planar superconducting undulator magnets (SCUs). The final design and the thermal model of this cryocooler-cooled LHe-based cryostat has been completed. The cryostat is fabricated and a preliminary cool-down test has been performed. This paper presents a comparison between measured and calculated thermal performance of the...
In high field applications, the HTS coils are commonly impregnated with epoxy resins for insulation and mechanical reinforcement to against the huge Lorentz forces. Till now, many of the epoxy impregnated ReBCO based HTS coils show some degree of performance degradation (Jc) due to thermal stress during cool down, electromagnetic stress during operation or any other reasons. It remains a...
Persistent current switches (PCS) which switch between superconducting and resistive states enrich the operation scenarios of superconducting magnets and lead to simple but colorful charging procedures. The state of a PCS can be controlled through superconducting phase change such as in temperature controlled case, global failure of flux pinning such as in over current controlled case, or a...
The demonstration fusion power plant DEMO by EUROfusion Consortium has now entered its conceptual design phase. DEMO is intended to demonstrate the necessary technologies for controlling a very powerful plasma, generating electricity consistently, and a reliable maintenance of the plant itself. Consequently, the plant design is a challenge not only for its physics conditions, but also for its...
We present the updated REBCO insert coil technologies applied to the 835-MHz REBCO insert (H835) for the MIT 1.3-GHz NMR magnet (1.3G). As a replacement for the previous 800-MHz REBCO insert that was damaged when it quenched during operation in 2018, we are constructing the 19.6-T H835 based on our new single-coil formation design with a stacked of 40 stainless-steel-co-wound no-insulation...
During the integrated commissioning of JT-60SA tokamak, the superconducting magnets have experienced several tests such as current ramps or fast discharges. The time variations of the associated magnetic field have induced AC losses in the winding pack (WP) of the magnets, i.e. hysteresis and coupling losses, and in the casing, i.e. eddy currents losses, of the toroidal field (TF) coils.
From...
Previously we reported our new circuit model, named as “B model”, for fast and effective simulation of a no-insulation (NI) high temperature superconductor (HTS) coil having a “single” defect. A primary benefit of the “B model” over the conventional distributed network model is to use only “five segments” of the defect-existing turn in an NI HTS coil, while a substantially larger number of...
The bearings of the flywheel energy storage system play an important role in supporting the flywheel, reducing frictional resistance, and ensuring the stability of the whole system. It is a key component that determines the energy storage capability, charging and discharging efficiency, and lifetime of the flywheel. The electromagnetic bearing is a multi-variable time-varying coupling...
The imaging quality of the Low-field magnetic resonance imaging (MRI) equipment is usually inferior to that of the high-field MRI equipment, however, the low-field MRI equipment has the advantages of lightweight, low cost, flexibility, etc., and is enough to meet most of the medical standards. With the progress of image reconstruction technology, the competitive disadvantage of the low-field...
In order to meet the needs of scientific research, a Multi-stage Ultrahigh and Magnetic System (MUMS) has been developed at Wuhan national pulsed High Magnetic Field Centre (WHMFC) for generating 100 T magnetic field. Based on multi-stage technology, MUMS is composed of outer, middle and inner coils with three corresponding pulsed power supplies, and the field waveforms from three coils are...
The DC fault current does not naturally generate zero-point, so it generates a large arc when cut-off operation. If it is failure to quickly extinguish the arc generated at the moment, lead to fire and equipment damage. Therefore, we proposed a fast and reliable transformer-type superconducting DC circuit breaker. The transformer-type superconducting current limiting elements are highly and...
No-insulation HTS magnets with high thermal stability and high current density have great advantages in the fabrication of ultra-high field NMR magnets. However, the turns of the double pancake coil of NMR magnet made by no-insulation technology are usually inconsistent with the theoretical value to keep the outer diameter of the coil consistent in engineering application, which affects the...
To study and explore the key technology of Ultra-high field MRI system, the 14 T body-size MRI magnet technology study activities has be launched by the Institute of Plasma Physics Chinese Academy of Sciences (ASIPP). The Nb3Sn Rutherford-type cables is designed for the conductor structure due to the 14 T magnet. The preload must be applied for the coil at room temperature, to counteract the...
The power exhaust represents a major challenge for the EUropean fusion reactor DEMOnstrator, asking for a new, robust design of the divertor, beyond the solution currently pursued for ITER. For this reason, the construction of a satellite fusion experiment, the Divertor Tokamak Test (DTT) facility, is being pursued in Italy. This compact tokamak, which must be very flexible in terms of plasma...
Abstract—The superconducting current limiter has the advantages of small on-state loss, fast fault response speed, and strong current flow capacity. It can quickly limit the short-circuit fault current in the power system and protect the safety of power equipment. Superconducting current limiters can be divided into resistive current limiters, inductive current limiters and hybrid current...
Three-phase transformer type superconducting fault current limiter (SFCL) using two superconducting module (SM)s between secondary windings, which consisted of three-phase transformer windings wound on three legs of E-I iron core and two SMs connected between secondary windings, were suggested and its fault current limiting fault current limiting and recovery characteristics using double...
Electromagnetic forming (EMF) is a high-speed forming process that has recently been explored in modern industrial applications to extend the forming limits of magnesium alloy or aluminum metal sheets. In this study, an experimental and statistical approach using analysis of variance (ANOVA) and response surface methodology (RSM) techniques is used to find the significant main and interaction...
We have succeeded in detecting local obstacles automatically in a 200-m-long RE-123 coated conductor (CC) by introducing deep learning based image recognition in reel-to-reel scanning Hall probe microscopy (RTR-SHPM). Longitudinal Ic homogeneity in CCs is one of the most important requirements for practical applications. Usually, such properties as Ic variation as a function of longitudinal...
In recent years, the REBCO tapes have a broad development prospect in the application of large high field magnets due to its high critical current density and superior mechanical property. Several conductors/cables with high carrying current capacity made of REBCO tapes, such as RACC, CORC, TSTC, RS, SSC, HTS-CroCo and Q-IS, are expected to fabricate cable-in-conduit conductor (CICC) or...
In a big admount of superconductive applications it is necessary to introduce an high temperature superconductivity stage, in order to realize the current lead.
In particular, in the superconductivity industial applications, it is also necessary to find the best compromise between the cost and the technical performance.
This paper presents the result of a geometrical and soldering...
The electrically excited high temperature superconducting (HTS) coils can replace the mover of the linear synchronous motor (LSM) for electromagnetic launching with an expectation of improving the motor’s efficiency. In this paper, three stators with different core and winding structures are designed for the LSMs with the movers made by HTS coils. The electromagnetic parameters of these three...
DC Interruption technology is essentially required as DC system and microgrid have increased. The Interruption technology also includes current-limiting technology, and it is suppressed the fault current that rises when the fault current occured. Until now, many hybrid Interruption technologies have been proposed in which a semiconductor element or a superconducting element is combined with a...
High temperature superconductor (HTS) coils have been applied in high field magnet applications, such as nuclear magnetic resonance (NMR) and maglev trains. The accurate calculation on the critical current of HTS coils is key for the magnet design and optimization. In practical applications, HTS tapes are also often wound into different shaped coils, such as racetrack coil for motors and ‘D’...
Among the current limiters whose performances were proved, there are many current limiters wherein their unique electrical characteristics are combined. Of these, the SFCL that uses coil and core are combined with a superconducting current limiting element and has a unique current limiting performance. Its applicability as a SFCL was proved. Especially, the initial current limiting operating...
As we all know, the motor equipped with hybrid magnetic bearings (HMB) is easier to get higher speed and higher power because HMB not only has the advantages of no friction and wear, but also has the advantages of high suspension force density and low power consumption. Therefore, HMB has important application value, especially in the field of high-speed direct drive. Until now, domestic and...
Deperming of ship has been conducted since the World War Ⅱ by several Navies and faces hard work for the deperming of large-size ships. We have been investigating a ship deperming system using High Temperature Superconducting coil laid flat on seabed of shallow water. The investigation started from the calculation of magnetic field to be imposed on ship. Considering deperming procedure, the...
A magnetic flux lens (MFL) exploits the induced screening current during an in-situ zero field cooling magnetization process to enhance the local flux density. It is a passive device being equivalent to an inner coil of a hybrid magnet. However, it requires no power supply and quench protection.
The magnetic flux lens has been first realized by using bulk HTS superconductors, and been...
To minimise the (alternate current) AC loss, multi-filament high-temperature superconducting (HTS) costed conductors (CCs) have been investigated for years. Many methods for striating the HTS CCs are developed and proven effective, such as laser cut and mechanical cut. This paper presents a novel approach to create the filamentary structure. Instead of cutting the HTS tape after manufacture,...
Marine energy power generation fits the concept of Sustainable Development Goals: SDGs because it is renewable, safe and widely available energy source. It is expected to be developed as a predictable energy resource in island nations and countries facing the sea since the force generated by seawater is persistent. Conventional generators are good for high-speed and low-torque fluid, so we...
NIMS has started design of a magnetic refrigerator to cool quantum computers. As well known, quantum computer is bringing a revolution to the world of super computers. In general, 3He-4He dilution refrigerators are used to cool the quantum computers at operating temperature below 100mK. However, dilution refrigerator uses a lot of helium 3, that is very expensive these days. On the other hand,...
The Comprehensive Research Facility for Fusion Technology（CRAFT）project is a key pre-research project of the China Fusion Engineering Test Reactor (CFTER) device in China. The manufacture of a full-size CFETR toroidal field（TF）coil is one of the key sub-topics of the CRAFT project, which is completed by the Institute of Plasma Physics Chinese Academy of Sciences (ASIPP). A hybrid...
For commercial large-scale magnet systems, the transient loss during the ramping process is an important evaluation metrics for refrigeration requirements, that is greatly influenced by contact resistance between winding turns. Due to intrinsic bypass current of no-insulation magnets, two part of the transient loss were considered: turn-to-turn loss generated by radial direction current, and...
We have proposed a novel method to adjust the magnitude and direction of current in the second generation(2G) high temperature superconducting (HTS) coil by providing a strong constant magnetic field. This method can be contactless used in a variety of flux pump devices, such as linear-motor type flux pump, rotating flux pump and so on. We have redesigned the experimental device on the...
The level of fault current increases as urban power grid expands rapidly in recent years. The traditional relay protection has difficulty in preventing increasing fault current damaging electrical devices in power grid. Magneto-biased superconducting fault current limiter (SFCL) is a novel technology with the ability of reducing the level of fault current in the first half of the cycle, which...
RF system is one of the key components of a 2 GeV, 6 MW high power FFAG accelerator being designed at China Institute of Atomic Energy. In order to verify the design principle and the engineering feasibility, a small scaled RF cavity is under construction, which can also be used as the main accelerating cavity for a 100 kW electron irradiation accelerator. By the deflections of several 180 deg...
7-filamentary Ba1-xKxFe2As2 (Ba122) iron-based superconductor (IBS) tapes were proven to be applicable to fabricate the high filed insert coils in recent years. The iron-based superconductors with ultrahigh upper critical fields have expected to be used in future high-field applications. However, the current 7-filamentary Ba122 tape is also sensitive to strain. In order to promote the...
The iron-based superconductor is a promising candidate for applications in polycrystalline forms owing to its high current transport performance under high magnetic fields. Especially, doped-BaFe$_2$As$_2$ (Ba122) is particularly interesting in terms of both small anisotropy and small weak-link issues [1]. Epitaxial thin films (ETF) of Ba122-type superconductors have been realized only with Co...
A HTS conductors test facility can be inserted in a 19.5 T @200 mm bore resistive magnet and operating temperature ranges from 4.5 K to 50 K with current up to 100 KA is under design. A superconducting transformer with a 200 A primary winding composed of immersion cooled NbTI conductors and a 100 kA secondary winding composed of force-flow cooled CICC as the current supply for HTS sample....
In order to meet the normal operation of HECRAL (Hybrid superconducting Electron Cyclotron Resonance ion source with Advance in Lanzhou) superconducting magnet, a cryostat in the form of immersed in liquid helium was designed, which integrated two two-stage GM cryocoolers, helium tank, thermal shield, outer dewar, suspension structures, maintenance tower, binary current leads, corresponding...
Within the framework of Open Science, set as a priority by the European Commission in Horizon Europe, the OPEN Super Conducting Cable (OPENSC2) code has been recently developed and released to grant the entire research community the possibility to analyse thermal-hydraulic (TH) transients in forced-flow superconducting (SC) cables for fusion and power applications. The code is...
In this paper, DC fault current limiting characteristics of the flux-lock type superconducting fault current limiter (SFCL) with parallel and series connection between two coils were analyzed.
The flux-lock type SFCL with parallel connection between two coils was composed of two windings connected in parallel and one superconducting module (SM), which was connected in series with the...
High field resistive magnets use Cu matrix composites as conductors because composites conductors have high mechanical strength. The conductors are manufactured by cold deformation that introduces high densities of obstacles to resist dislocation motions. The increased density of these obstacles increases the mechanical strength of the conductors. Under cyclic loading, such as the loading...
This paper describes the design activities on the Toroidal Field (TF) conductor and coil of the DEMO Nuclear fusion power plant. As prototypes of future commercial tokamaks, DEMOs are expected to be able to produce cost-effective electrical power. In this view, an optimized design becomes a crucial aspect in the whole engineering design procedure. The 2018 baseline of DEMO reactor includes 16...
Along with development of hydrogen-use, sustainable society in which it is used as clean energy source as well as energy storage material, MgB2 superconducting power applications have been attracted scientific interest due to its huge potential of superconducting characteristics, made from affordable elements and applicability to liquid hydrogen cooling. As MgB2 wires have been commercially...
Abstract: The High Energy Photo Source (HEPS) is been built in China and the magnets are in batch production. The octupole magnets with skew quadrupole component used in the storage ring have been designed and manufactured. This magnet has an aperture of 30mm, a field gradient of 735000 T/m3 and a length of 0.26m. Different design schemes are compared. The magnet consists of 2 yokes and 4...
An electron cyclotron is to heat a plasma by driving current in a fusion system. This system requires strength and accurate magnetic field distribution for the interaction of the electron beam and radio frequency wave energy. The magnet of the system consists of a conduction-cooled superconducting magnet for 7 T and structures connected with a 2nd stage GM cryo-cooler of 1 W at 4 K for cooling...
The output power of high stability dc power supply system which drives the water-cooled magnet of Steady High Magnetic Field Facility (SHMFF) can reach up to tens of megawatt, so that the circuit usually adopts the realization scheme of Silicon-controlled rectifier plus LC filter. And in order to generate low-ripple magnetic field required by the High field nuclear magnetic resonance and other...
A novel Canted-Cosine-Theta (CCT) coil technology is first proposed and applied to the HIAF (High Intensity heavy-ion Accelerator Facility) fragment separator, which can offer the absence of multipole components and meet the requirements of high magnetic stiffness (25 Tm). In this paper, a half-aperture CCT multipole prototype was built and successfully tested by the Superconducting Magnet...
In September 2020, a 4-year national project was embarked on to develop a conduction-cooled 6 T 320 mm all-HTS magnet for MRI with support from the Korea Medical Device Development Fund. It is a collaborative R&D effort led by SuperGenics, Co. Ltd., in participation with Changwon National University, Korea Electrotechnology Research Institute, Korea Maritime and Ocean University, Korea...
Recently, energy production and cooling technology using hydrogen has been developed worldwide. In particular, the ortho-para conversion process, which was a problem in hydrogen liquefaction, was overcome through the development of catalysts. Hydrogen has been an attractive material as a refrigerant due to its low liquefaction point and high thermal conductivity. In superconducting...
A system based on a novel scheme for generating the repetitive pulsed high magnetic field (RPHMF) is developed and applied to enhance the performance of NdFeB electrocatalyst in alkaline water electrolysis for the first time. In this system, the scheme for generating continuously high-frequency pulses depends on the cooperation of multiple power modules with new structure. Multiple power...
As part of the U.S. contribution to the HL-LHC Accelerator Upgrade Project (AUP), Fermilab is designing and building cold masses suitable for use in the LHC interaction regions. The cold mass provides a vacuum-tight helium enclosure for the magnets. Two magnets are aligned both axially and in cross section at Fermilab based on survey and warm magnetic measurements. Bus work and...
A desktop 300MHz nuclear magnetic resonance (NMR) superconducting magnet with conduction-cooled cryostat system was developed in Institute of Electrical Engineering, Chinese Academy of Sciences (IEE, CAS). The magnet has a standard 54mm-diameter warm bore with length 600mm, and the 5 Gauss line is actively shielded within the region 650mm (z) ×400mm (r). The operating current is 111.46A with a...
The superior electromechanical properties (EMP) of REBCO coated conductor (CC) tapes made them enabled to be utilized in a wide range of practical superconducting applications such as coils, magnets, and generators. However, the extreme application environments degrade the current-carrying capabilities so it is important to develop a technique to evaluate the EMPs and their reversible limits...
Iron-based superconductors (IBSs) are regarded as promiscing candidate for high magnetic field applications because of its relatively high superconducting transition temperature (Tc), and nearly isotropic upper critical field (Hc2) ~100 T. Amoung various IBSs, AEAFe4As4 (AE = Ca,Sr,Eu, A = K, Rb, Cs, 1144)[1] superconductors are one of the most recently developed IBSs with several unique...
The results of the development of a magnetic system for bending an electron beam in the industrial accelerator ILU-10 will be presented.
The ILU-10 accelerator has an operating energy range of 2.5–5 MeV. The available design allows to eject electrons only vertically. However, there is a demand for the ability to eject a beam bended at 90 °.
The paper presents two ways to solve this problem....
MgB2 has been regarded as the most attractive candidate for the next-generation superconducting material due to its high critical temperature and low material cost. Sam Dong Co., Ltd., Korea, is a supplier that produces a variety of the MgB2 superconducting conductors to meet customers’ requirements over the past 6 years. Recently, we have increased the area fraction of...
Abstract: Superconducting joints are essential for persistent-mode operation in a superconducting magnet system, the resistance has to be around 10-14-10-12 Ω thus to produce an ultra-stable magnetic field. Based on the national collaboration program of the MRI for small animals, the development of superconducting joints between bronze-route Nb3Sn multifilamentary wires manufactured by...
Quench and protection in magnets wound with coated conductors is of great interest for many applications, including those of high energy physics accelerators. The relatively large slow normal zone propagation and large MQE of coated conductors and the potential of burn out in well insulated coils has led to an interest in non-insulation coils. A stability of block type dipole magnets wound...
The named fully superconducting magnetic bearing (SMB) consists of a rotor of high temperature superconducting (HTS) bulk of YBaCuO and a stator wind of HTS coated conductor tapes. The fully SMB has been developed a prototype and under operation in Japan. The dynamics of fully SMB under long term operation is vital to engineering applications, however, the experimental and theoretical studies...
When the HTS tapes in the quasi-isotropic cable are insulated in middle but soldered together at terminals, it is call partially coupled quasi-isotropic cable. There are resistances at soldered parts which would form closed current loops. When the cable is carrying DC current and subjected into AC magnetic field at the same time, it would induce coupling current and change the current density...
We are presenting a detailed study of the magnetization of CC-tapes stacks by the flux pump method. Magnetization of a CC-tapes stack was carried out using repeated cyclical impact of a local magnetic field source. The size of the localized area of the external magnetic field was five times smaller than the size of the HTSC sample.
A commercially available 12 mm wide CC-tape from SuperOx was...
We experimentally studied the quench characteristics of coated conductors wound on metal cores spirally. The length of the metal core of each sample was 230 mm. A coated conductor was wound at the center 160 mm section of the core. Current terminals were attached over the coated conductor with 100 mm separation (effective section). Indium was filled in the gap between the current terminal and...
The iron-based superconductor (IBS) is a good candidate for high field magnet applications. The bending effect and properties of IBS tapes were systematically investigated in this work. The bent Ba1-xKxFe2As2 (Ba122/Ag/AgSn) 7-filamentary tapes with different bending diameters (D=10, 15, 20, 25, 30 mm) were prepared by wind-and-react method. A special mechanical structure was used to prevent...
Improvement of mechanical stability of superconducting cables under high mechanical loads is one of the most important challenges for their industrial application. Provided that impregnation is commonly adopted to protect coil wound by superconducting tapes from mechanical disturbance caused by Lorentz force generated from magnetic field and rotational vibration of machines such as motor, this...
In MuSEUM experiment at J-PARC, we are working on precise measurements of the muon hyperfine structure in the ground state. We are currently developing a device for experiments in a high magnetic field (1.7 T) in order to achieve higher precision than the previous experiments. For high-precision measurement of muon hyperfine structure, it is essential to improve the magnetic field accuracy in...
With commercialization of high temperature superconducting (HTS) RE (RE= rare earth) Ba-Cu-O tapes, it is extensively applied in the superconducting magnets with high magnetic field due to its high critical current density and excellent mechanical properties compared to low temperature superconducting (LTS) conductors. However, it is difficult to realize the persistent current mode (PCM)...
As the efficiency of ordinary linear motors for electromagnetic launching is not high enough, the high temperature superconducting linear synchronous motor (HTS-LSM) is proposed with an expectation to improve the efficiency. This research focuses on a unilateral type HTS-LSM which mover is made up of closing coils pre-excited. In the research, the motor’s electromagnetic thrust characteristics...
Due to the use of high-performance permanent magnet, hybrid magnetic bearing (HMB) has the advantages of compact structure, high levitation force density and low power consumption. In particular, the six-pole AC HMB can be driven by a three-phase inverter to generate radial two degrees of freedom (2-DOF) suspension force with low cost, symmetrical structure, good linear force current...
No-insulation (NI) high temperature superconducting (HTS) machine is a kind of synchronous semi-superconducting machine with high power density and enhanced thermal stability. This technique has a great potential for electric aircraft propulsion systems, in which the NI HTS coils are used as rotor windings. However, NI HTS coils suffer from eddy currents flowing through turn-to-turn contacts...
In general, the field coils of a superconducting motor or generator need to be impregnated with epoxy resin to protect the coils from mechanical stress occurring during rotation. Recently, various studies that have been conducted to optimize the epoxy impregnation method revealed that coils impregnated by the vacuum pressure impregnation (VPI) method have superior thermal and electrical...
Field pole magnet composed of stacks of high-temperature superconducting (HTS) tapes is a featured technology due to its simple manufacturing process, flexibility, and high current density thanks to intensified characteristic of HTS characteristics.
In this study, our group measured magnetic distribution of rounded stacks of HTS tapes in comparison with flat shaped ones. Normally, critical...
The JT-60 Super Advanced (JT-60SA) magnet system consists of toroidal field (TF) coils, central solenoid (CS), and equilibrium field (EF) coils, and all coils are thermally protected by a thermal shield. The CS consists of four stacked modules with 52 layers, and the conductor is designed with a cable-in-conduit conductor (CICC). The CS is cooled to an operating temperature of 4.5 K by...
In order to design a pulsed electromagnet, it is necessary to consider eddy currents that depend on the pattern shape of the pulse excitation, and to design the structure and set the operating parameters considering the fluctuation of the magnetic field distribution and its effect on heat generation. Evaluation tests of a new bump magnet for the J-PARC RCS showed that the magnetic field...
Recently, a Wireless Power Transmission (WPT) system has been attracting attention for automobiles and electric railways. However, the power transmission efficiency in the conventional WPT system composed of copper coils is not high enough due to large resistance. Therefore, we have investigated the effectiveness of applying REBCO coils to WPT system. Since the increase AC loss of the REBCO...
The Divertor Tokamak Test (DTT) facility [1], under construction in Frascati, Italy, will rely on a fully-superconductive magnetic system. Thanks to the limited dimension of the machine, three cryo-lines will house all the Feeders for the Central Solenoid (CS), for the Toroidal Field (TF) and for the Poloidal Field (PF) coils, respectively. The in-cryostat route of the different Feeders (two...
Abstract
This work presents an experimental study on electromagnetic and thermal behaviors caused by a quench propagation on a no-insulation (NI) high temperature superconductor (HTS) coil. To observe quench behaviors of NI HTS coil, 25-turn NI single pancake test coil was wound, and an overcurrent experiment was performed in conduction-cooled condition. Since the quench is a local and...
Recently, permanent magnet synchronous motors(PMSM) are widely used in industrial fields due to various advantages such as high speed operation, high efficiency, and compact design. However, PMSM has the disadvantage of noise and vibration caused by high magnetic energy during the interaction between the stator and the rotor magnet. These drawbacks have a significant impact on machine...
AC applications of REBa2Cu3Oy (REBCO) superconducting tapes require large current capacity and low AC loss properties. We have already proposed transposed parallel conductors in our previous study on the development of superconducting power transformers and rotating machines. The parallel conductor with the optimal transposition does not induce the additional AC loss. However, if the...
The ground semi-physical simulation experiment is essential for the reliability verification of micro satellites equipped with micro thrusters. The HTS translational system based on the complete diamagnetism of superconductors is a feasible scheme. In order to explore the levitation force, translational characteristics and the factors affecting the performance of superconducting translational...
REBa2Cu3Oy (RE123) melt-textured bulks are expected for high field applications using their excellent field trapping properties. RE123 melt-textured bulks are typically fabricated using the Top-Seeded Melt Growth (TSMG) or Top-Seeded Infiltration Growth (TSIG) method where bulks are melt grown from the seed crystals placed on top of the pellets, which...
One of the properties in superconductor is perfect diamagnetism called as Meissner effect. Among superconductors, YBa2Cu3O7-δ (YBCO) polycrystals has high critical temperature (Tc) over 90 K and high critical current density (Jc) of the order of 104 A/cm2 at 77 K in self-magnetic field［1］, so it is expected as a material for shielding magnetic field under liquid nitrogen cooling. Concerning to...
Abstract— Fermilab is fabricating ten full length cold masses for the high-luminosity Large Hadron Collider Accelerator Upgrade Project (HL-LHC AUP). One practice assembly and one pre-series assembly have been completed. This paper summarizes the construction details. Topics include incoming inspection, bus assembly, component machining, shell forming, beam tube insertion, bus expansion loop...
Three-phase transformer type superconducting fault current limiter (SFCL) using secondary windings with closed loop, which consisted of three-phase transformer windings wound on three legs of E-I iron core and two/three superconducting modules (SCMs), were suggested and its fault current limiting operations according to ground-fault types were analyzed. To verify the effective operation of the...
Dry magnets using MgB2 wires are one of effective options to eliminate dependence on liquid helium in MRI scanners. In the dry magnets, however, lack of thermal mass of cryogen makes a controlled quench difficult and extends time for restarting the magnets after the quench. In this study, a novel rapid ramp-down procedure, which can be substituted for the controlled quench in emergency...
A conventional rectifier based on a thyristor is widely used as a magnet power supply in the largest tokamak fusion device such as JT-60SA and ITER. The rectifier converts AC input power to DC output power supplied to the magnet bi-directionally. In order to energize and de-energize the magnet controlling power flow, the rectifier shifts phase angle of AC current with reference to input AC...
Nb3Sn strand was used to enable the development of short (1.4 m) segmented coil designs, as opposed to the nearly 2 m long compensated solenoid designs needed for NbTi machines. Using Nb3Sn strand will allow a conduction cooled design, if quench is properly managed. We modeled two designs with magnetic field homogeneity better than 10 ppm (part-per-million) within DSV (Diameter of Spherical...
Cryo-assemblies with the low-beta Nb3Sn quadrupoles for the high luminosity LHC (HL-LHC) upgrade will be tested at Fermilab’s magnet test facility. Total of 10 cryo-assemblies will be delivered to CERN within the US HL-LHC Accelerator Upgrade Project (AUP). The horizontal test stand at Fermilab already has been used for testing the existing LHC inner-triplet quadrupoles, but the stand and...
Aiming at the very small-scale NMR magnets, the authors have studied to detect NMR signals for NMR relaxometry using the single-sided magnetic pole which contained the high temperature superconducting (HTS) bulk magnet. The NMR signal relaxation rate depends on the mobility of molecules, including fluctuations and diffusion, in the microscopic environment. This measurement method can acquire...
Electrodynamic suspension (EDS) system is promised to be the ideal option for high speed magnetic levitation transportation. The electromagnetic forces for levitation and guidance of the EDS system are based on the relative motion of onboard superconducting magnets and the null-flux coils fixed on the ground. This unique working principle requires an auxiliary device to suspend the vehicle at...
As is known, heat losses through current leads largely determine the economic efficiency of the superconducting systems. Much attention is paid to the design of optimal current leads, but the benefits of standard approach are physically limited by the Wiedemann-Franz law. An innovative way to further reduce heat inflow is to use current leads equipped with Peltier thermoelectric elements....
The electrical and physical properties of $\mathrm{Nb_3 Sn}$ strands are strongly dependent on the heat treatment during which tin diffuses into niobium by solid-state diffusion. During diffusion, $\mathrm{Nb_3 Sn}$ grains grow at the Nb/bronze interface. The shape and size of the grain depend on the temperature of the last step of the heat treatment, its duration and the size of the Nb...
As the use of renewable energy increases in the future, hydrogen production is predicted to increase significantly. As the amount of hydrogen used increases, it is more cost-effective to transport in liquid hydrogen state than to transport in high pressure gas form. So, the more liquid hydrogen is used, the greater the opportunity for the high-temperature superconducting coil to cool the...
One of the problems with the practical application of high-temperature superconducting coils is burnout due to the heat generated by a local low critical current density. At the current level of manufacturing technology for a high-temperature superconducting tape, it is not possible to manufacture long high-temperature superconducting tapes that do not completely include deterioration of local...
When a hotspot occurs in a conduction-cooled HTS superconducting winding, decrease of heating at the hotspot and decrease of local temperature rise are necessary. In order to do that, good thermal conduction around the heat-source materials such as an electric-insulation film on the HTS tape and a non-metallic structural material is important. The electric insulation materials are generally...
Generally, the double sided linear HTS induction motor has higher propulsive force and higher efficiency because the HTS windings can carry higher current with lower loss. In this paper, the primary side of the proposed linear motor is made from silicon steel sheet, and ReBCO HTS tapes are used to wind the armature windings which are settled into the iron core. The secondary sides are made...
MgB2 has the highest Tc of 39 K among metallic superconductors [1] and is expected for applications at 10-20 K. MgB2 bulk permanent magnet [2] is interesting for compact, high field magnet applications. Recently, we developed the Magnesium Vapor Transportation (MVT) method [3] that transports magnesium vapor to precursor boron pellets. By using the MVT method, we have succeeded in obtaining...
The finite element analysis of electromagnetic coupling between a stainless steel shell and the 100 T pulsed magnet has been developed at the Wuhan National High Magnetic Field Center (WHMFC). The 100 T pulsed magnet consists of inner, middle and outer coil coaxially nested. The stainless steel shell is fitted tightly around the middle coil to resist the strong Lorentz force. The thickness of...
BOnding eXperiments (BOX) are a novel, affordable and fast benchmarking solution aiming to reproduce specific mechanisms of training and performance limitations in Nb3Sn and Nb-Ti superconducting magnets. The BOX samples are tested at the University of Twente at 4.2 K within a solenoidal background field with sufficiently high magnetic forces. Following conventional manufacturing processes,...
The JT-60SA large research tokamak is being constructed by the National Institutes for Quantum and Radiological Science and Technology (QST) in Japan, as a satellite tokamak project designed to complement the International Thermonuclear Experimental Reactor (ITER) and to produce demonstration data for use in the proposed DEMOnstration Power Plants (DEMO). JT-60SA started cool-down phase in...
This paper presents calculation results of time-varying behavior of no-insulation (NI) high temperature superconductor (HTS) field coil for synchronous motor considering armature reaction and slotting effect. Despite the direct current (DC) operation in synchronous motor with HTS field winding, NI field coils are under time-varying conditions caused by rotor field harmonics depending on...
Switched reluctance motors (SRMs) have many excellent advantages of inherent simple structure, good fault tolerance, high rotating speed, high power and robustness. Magnetic bearing (MB) preserves the characteristics of no friction, no lubrication, free maintenance and long life. Bearingless switched reluctance motor (BSRM) integrates the functions of the SRM and MB. Therefore, the BSRM is...
Superconducting magnetic bearing (SMB) is a promising candidate for flywheel energy storage systems due to its great advantages of low friction loss, long-life operation, and maintenance-free. Since the amount of the SMB stored energy is strongly related to its levitation force, in this work, we have proposed a novel structure of hybrid superconducting stator which combines the HTS bulks and...
The electron cooling technology is applied in the spectrometer ring (SRing) for HIAF to boost the luminosity of high-density beam. There are 4 kinds of main coils are used to offer longitudinal field along electron path. In this paper, the three-dimensional magnets of the electron cooler are analyzed. The model consists of a gun section, two 90° angle toroids with a radius of 1 m, a cooling...
The Helmholtz Zentrum Berlin (HZB) developing a new synchrotron light source, BESSYIII, as successor to the excellent 3rd generation light source BESSYII. The BESSYIII storage ring will be designed for a beam energy of 2.5GeV and Multi bend achromat (MBA) optics for low emittances of 100pm-rad. In parallel to optimizing the optics of the MBA cells, we are starting to develop various magnet...
The Neutron Spallation Source (SNS) at ORNL upgrade from 1.0 GeV to 1.3 GeV is in progress now. There are number of water-cooled magnets which should be upgraded to transport 30% of higher beam energy. There were designed new Chicane Magnets, Injection/Extraction Septum Magnets, and Lambertson Magnet. The magnetic designs were a challenging task because new magnets must have a good combined...
A ferromagnetic shimming has been applied to improve the field homogeneity of NMR magnets. The study deals with the results of evaluating the magnetic field distribution for a 400 MHz all-REBCO NMR magnet at the 20 mm DSV(diameter sphere volume) with mapping experiments. The mapping path consists of 128 positions that moving along the surface of the cylinder 24 mm in diameter and 30 mm in...
One of the practical applications of the second generation HTS tapes (or CC – coated conductors) lays in the area of development of superconducting magnetic energy storages (SMES). In particular, HTS SMES will be applied for charging pulse mode magnets used in particle accelerators. The important particularity of such magnets is the rapidly changing operating current and magnetic field at low...
Cable-in-conduit conductors (CICCs) are applied in the superconducting magnets designed for fusion reactors, because of their high-engineering current transmission capacity and large heat removal capabilities. In previous research, CICCs exposed varying degrees of performance degradation during electro-magnetic (EM) loading cycles. To prevent this kind of degradation, CICCs must be designed...
In previous studies, Jc-strain relation in the reversible range and the irreversible external-tensile strain (ε_irr_t) of MgB2 filament were reported. In general, it is said that ε_irr_t is almost equal to the pre-compressive strain caused by cooling after heat treatment. In this study, the irreversible external-compressive strain (ε_irr_c) of MgB2 multifilament wire was measured. In...
Performances of ultra-high field superconducting magnets have been improving. On 2017, a world-record high magnetic field of 45.5 T was generated with insert no-insulation (NI) Rare-Earth Barium Copper Oxide (REBCO) pancake coils (14.4 T), called “LBC3”, and an outsert resistive magnet (31.1 T). After 45.5-T generation, the insert NI REBCO pancake coils were quenched, and plastic deformations...
A major problem of state-of-the-art Nb3Sn accelerator magnets is their long training due to thermo-mechanical perturbations. Increasing the specific heat, Cp, of the Rutherford cable would reduce and/or eliminate training by limiting its temperature rise. This paper studies feasibility of increasing the Cp of Nb3Sn Rutherford-type cables by using composite Cu/Gd2O3 and Cu/Gd2O2S tapes produced...
A major focus of Nb3Sn high field accelerator magnets for HEP is on significantly reducing or eliminating their training. Samples of NbTi and Nb3Sn wires and Rutherford cables were impregnated with organic olefin-based thermosetting dicyclopentadiene (DCP) resin, commercially available as TELENE® by RIMTEC Corporation in Japan, mixed with high heat capacity ceramic powders. The high heat...
The cost of high-field NMR systems has led to the development of low-cost ‘benchtop’ instruments for use by academic and commercial institutions. Whilst these devices have made NMR-spectroscopy more accessible, their use of permanent magnets limits the available resolution. Bulk high temperature superconducting (HTS) materials offer a route to bridge the performance gap to high-field...
Due to the wide application of non-linear loads and switching electronic devices, the current in the power grid is often mixed with many harmonic components. The non-sinusoidal currents will have certain effect that unstable voltage and increased heat dissipation on electrical equipment made of superconducting materials, such as superconducting motors, SMES and HTS magnets. In this paper, In...
A no-insulation (NI), cryogen free HTS MRI magnet is currently being developed at the Robinson Research Institute. Consisting of 23 double pancake coils of varying size, width and REBCO material, the magnet is designed to image the human brain (1.5T of moderate uniformity, +/- 150 ppm over a 200 x 150 ellipsoidal imaging volume).
Risk of a quench arises from several sources, such as defects...
High-temperature superconducting REBCO coated conductor is one of the main candidates for next-generation high field magnets in fusion reactors and particle accelerators owing to their high current-carrying capability. While these materials can operate at higher temperatures and generate higher magnetic fields than their counterparts with lower critical temperatures, protecting the REBCO...
One of the most actual problems of modern physics is the development of powerful radiation sources in the THz band. At the moment, the highest pulse and average power in the THz band are realized by the fast-wave devices – free-electron lasers and gyrotrons. The gyrotrons are vacuum electronics devices based on the stimulated cyclotron radiation of electrons moving along helical trajectories...
Pb–Bi alloy and Wood's metal have been used for more than 30 years as representative superconducting solder intermedia to establish superconducting joints between NbTi and Nb3Sn wires. However, the use of Pb and Cd has been severely restricted by environmental regulations. The author has developed a novel alternative superconducting joint method between NbTi and Nb3Sn wires without Pb and Cd....
NbTi superconductors with large cross-sectional area of high purity aluminum are used in accelerators, SMES, and fusion devices to improve their stability. The Large Helical Device (LHD) is a Heliotron-type fusion experimental device, which consists of a pair of superconducting helical coils and three pairs of superconducting poloidal coils. The LHD conductor used for the helical coils is a...
Development of High Temperature Superconductors (HTS) electrical machines results in applications of various fields, (linear machine, axial field machine), as they have higher efficiency and power density. Numerical modeling of superconducting electrical machines is usually performed by finite element method based on their electrical behavior. H-formulation of the Maxwell’s equations, is one...
Full superconducting generator uses superconducting magnets wound with HTS tapes to replace copper wires to form a strong magnetic field. As far as superconducting magnets are concerned, stabilization is the guarantee of reliable operation of superconducting magnets, because in the operation of superconducting magnets, small changes in temperature, magnetic field or current will cause magnetic...
Conductor on round core (CORC) cables composed of YBCO coated conductors and a former show significance in high current capacity and mechanical flexibility. However, YBCO coated conductors are vulnerable to a local quench, and this disadvantage can affect the thermal stability of the CORC cables. Therefore, this paper first develops a 3D electromagnetic-thermal cable model with the termination...
Abstract gradients minimized in order to retain thermal and operating margin. We have used 3D finite element method (FEM) simulation in COMSOL Multiphysics software to calculate the temperature distribution both along the winding direction and across the cross-section of an MRI segment coil at its equilibrium operating temperature. We have also modelled the evolution of the thermal...
One of the problems with a superconducting magnet is heat leak from the external environment to the inside of the cryogenic devices. In order to suppress the heat leak, the wireless charging has been proposed. Therefore, superconducting diode is expected as a novel rectifying element operating at cryogenic conditions [1]. In our previous study, we reported that YBa2Cu3Oy(YBCO) films grown on...
Superconducting flywheel energy storage system (SFESS) has the advantages of fast response, high power density, long life, unlimited charge and discharge and pollution-free. With the improvement of the mechanical properties of superconducting magnetic bearings（SMBs）, it will be a better choice for SFESS to adopt fully-superconducting bearing composed of HTS coil stator and HTS bulk rotor. Due...
Generally, the wind and react process is used to manufacture MgB2 coil. The react temperature is relatively high, around 650 °C, and this may increase the magnetic field inhomogeneity as a result of the distortion of the winding former. To solve this problem, Kiswire Advanced Technology has developed a twisted cable with fine MgB2 strands that can be wound after heat treatment. In this study,...
The No-insulation (NI) coil's turn-to-turn current paths prevent local heating by forcing the current to bypass into nearby turns when a hot spot appeared in a coil. However, the bypassing current will reduce the magnetic field that generates unwanted induced currents in the adjacent coils in a multiply-stacked HTS magnet. This induced current can temporarily exceed the designed maximum...
A nuclear magnetic resonance (NMR) magnet system equipped with a persistent current switch (PCS) operates efficiently without Joule loss in persistent current mode (PCM). The superconducting joint technique and a persistent current switch (PCS) are essential to develop the PCM. In this study, we fabricated NbTi superconducting joints and measured the resistance of these joints. Based on the...
REBa2Cu3Oy(RE123, RE: rare earth element) melt-textured bulks are used as superconducting magnets using their high field trapping (BT) properties. Their BT performances are enhanced by both enhancement of critical current density (Jc) and an increase in size of the bulks. We prepared all c-grown Gd123 melt-textured...
Superconducting (SC) current feeder system is an integral part of a large-scale superconducting magnets based machines like a tokamak or accelerator. One end of the SC feeder is connected to SC feeder of magnet and another end is connected to the power supply via current leads for powering the magnet. So far, low temperature superconductor (LTS) is the popular choice for such applications....
Paschen failures in ITER and W7-X superconducting coils at the acceptance tests have shown that it is highly desirable to lower the coil discharge voltage of the DEMO TF coils. Another benefit of lowering the discharge voltage might be the reduction of the number of coil feeders, i.e. connect in series the TF coils inside the cryostat, which is attractive for machine integration. For a given...
Divertor Tokamak Test facility (DTT) is the device devoted to tackle the power exhaust issue in the view of future fusion power plant [1]. The DTT construction is nowadays started in the ENEA site of Frascati, Italy. The DTT superconducting magnet system is comprised of 18 Toroidal Field (TF) coils, able to generate a magnetic field of 6 T at the plasma major radius (i.e., at 2.19 m from the...
Single-grain REBaCuO superconducting bulks have significant potential as a trapped field magnet (TFM) because they can trap a magnetic field, BT, over several tesla. To enhance the BT value, reliable seeding methods for the fabrication of REBaCuO bulks is essential to increase critical current density, Jc. The top-seeded melt growth (TSMG) technique is a well-known growth method to...
Chris Reis1,2, Laura Garcia Fajardo1, Tengming Shen1
1. Lawrence Berkeley National Laboratory, Berkeley, CA, 94720
2. University of California, Berkeley, CA, 94720
High temperature superconducting magnets have the potential to generate magnetic field of greater than 20 T for compact fusion reactors, particle physics colliders and nuclear magnetic resonance. A key remaining technology...
We designed and fabricated a prototype high temperature superconducting(HTS) sextupole magnet for the chromaticity correction of an asymmetric–energy collider, named SuperKEKB. The HTS sextupole magnet consists of six two-layer-rectangular REBa2Cu3Oy(REBCO) coils, which are wound with a 4-mm-wide coated conductor and impregnated with the epoxy resin. In this study, we measured quench...
A Linear synchronous motor (LSM) is more electrically and mechanically efficient as compared to a linear induction motor (LIM) when it is running at high speed. Therefore, LSM is especially suitable for maglev which is usually operated over 400 km/h. To acquire stronger thrust force, high-temperature superconducting (HTS) magnets are proposed to replace traditional permanent magnets or...
The stability of a levitation transport system using a bulk superconductor levitated above a permanent magnet rail has been studied. We investigated the inclination of the superconducting shuttle to improve the stability of the superconducting levitation transport system. The roll angle of the superconductor shuttle was estimated by measuring the magnetic force acting on each part of the...
Recently, we proposed a REBCO split wire having multi-core structure. The split wire is fabricated by separating the REBCO layer using the commercial REBCO-coated conductor. The fabrication method is electrical separating by bending stress (ESBS) and electrical separating by pressure concentration method (ESPC) [1]. In the measurement of the screening current induced magnetic field, that was...
In order to accurately evaluate the reliability of Pulsed High Magnetic Field Facility (PHMFF) at Wuhan national pulsed High Magnetic Field Centre (WHMFC), a reliability analysis method based on Markov chain and reliability block diagram is introduced in the paper. PHMFF is composed of lots of pulsed power modules, magnet coils and its corresponding control system. Based on the hardware of...
A refrigerant circulation cooling system for a HTS (High Temperature Superconducting) coil shows better cooling performance than a heat conduction cooling system when the distance between a cryo-cooler and the HTS coil becomes large because the temperature gradient between the coil and the cryo-cooler becomes small. By combining this excellent cooling system with magnetic refrigeration...
The homopolar hybrid magnetic bearing (HHMB) has the characteristics of the same air gap magnetic field direction, simple manufacture and assembly, low hysteresis and eddy current loss because the axial magnetized permanent magnet is often used to provide bias flux. Therefore, the HHMB has often adopted to suspend the rotor of the high-speed motorized spindle to obtain good performances of...
Commercial HTS coated conductors exhibit asymmetric Ic (B,θ) characteristics, where θ is defined as the angle between the applied magnetic field and normal component of the superconductor plane. Previous works reported influence of Ic (B, θ) characteristics on dynamic resistance in a coated conductor and AC loss of coil windings wound with coated conductors. However, the influence of...
Superconducting magnets in fusion reactors are subjected to a huge electromagnetic force of >100 MN/m. The magnets have to be sustained with a structure with a strong body to avoid high stress and deformation. Extrapolating existing fusion experimental device constructed ever, the total weight of the magnet system, i.e., the magnet and support structure, of a commercial fusion reactor is...
REBCO melt-textured bulks are expected for strong magnet applications utilizing their high field trapping properties. Typical REBCO melt-textured bulks consist of a-growth and c-growth regions depending on the growth directions from the seed crystal placed on top of the pellets. We have developed a new method, Single-Direction Melt Growth (SDMG) method, for fabricating REBCO bulks wholly...
One of the biggest weaknesses of superconducting coils is that the coil burns out when quick action is not taken at the moment of quench. It is known that the no insulation (NI) technology of the high temperature superconducting (HTS) coil almost solved the problem of burning the coil by this quench. In HTS coil applications, the larger coil sizes and higher generated magnetic field strengths...
Superconducting Magnetic Energy Storage (SMES) has the characteristic of fast response and high power density, which can be used to enhance the stability of power system and improve the power quality. With the increasing capacity of the power system, the application of a single SMES has certain limitations. By integrating individual superconducting magnet unit or SMES unit, modular SMES...
A number of programs aimed at modeling electrical, magnetic, thermal, and mechanical transients in superconducting magnets and circuits were developed at CERN as part of the STEAM (Simulation of Transient Effects in Accelerator Magnets) project. The framework includes software to accurately model quenches in a superconducting magnet, either self-protected or protected by energy-extraction,...
A structural model has been developed for the VIPER cable, which is based on the Twisted Stacked-Tape Cable (TSTC) design and has four slots each containing 50 REBCO HTS tapes. Each slot contains a TSTC and the entire void space is filled with solder. The four slots are arranged around a central cooling channel. It is developed by Commonwealth Fusion Systems (CFS) in collaboration with the...
High-quality magnetic resonance imaging (MRI) techniques can provide precise anatomical details of small extremities such as hands and feet. Conventional MRI systems use cryogenic superconducting magnets cooled by liquid helium, and these occupy a large amount of space. Therefore, we have been developing a compact and high-performance desktop finger MRI system using REBCO wires. The proposed...
For the electrodynamic suspension (EDS) system that uses superconducting magnets, the transmission efficiency of no-contact on-board power source will be affected by the eddy current loss generated on the outer wall of the cryostat. To address this issue, improving the structure of the generator coils is an effective approach. In this work, we have carried out the optimization of the...
As an industrial application of the high-temperature superconducting coils (HTS coils), for example, an induction heating device that rotates a metal in a DC magnetic field by a superconducting coil have been studied. For that purpose, when operating the HTS coils, it is necessary to remove the heat from the coils and keep those at about 50K or less. In addition, assuming application to...
The magnetic bearing using the pinning effect of the high-temperature superconductor (HTS) has been developed. The rotor composed of the permanent magnet levitates without control with levitation gap g = 10 mm due to the pinning effect of HTS. In order to give the function of the secondary side of the induction motor (IM) to the magnetic bearing, a force other than the rotation direction due...
Abstract : To cool the superconducting magnets of compact synchrotron, a forced flow cooling system based on GM/J-T concept with cooling capacity of 10 watts at 4.5K is researched. The cooling system consists of heat exchanger, precooling system, J-T valve and forced flow cooling tank. In refrigeration process, high pressure helium is cooled by the heat exchanger and precooling system, and...
In the superconducting magnet system, which is the core equipment of the fusion experimental device, a large number of measuring equipment are installed in the system for the operation and monitoring of the system. Although each measuring equipment is inspected and repaired during the maintenance period of the experimental device, there is a concern that trouble may occur in the measuring...
We have been developed the compact NMR magnets consisted of the stacked high temperature superconducting (HTS) bulks trapped by a field cooling (FC) method. The HTS bulk annuli magnet for compact NMR relaxometry operating in liquid nitrogen was analytically designed and experimentally demonstrated. On the other hand, the high-quality magnetic resonance imaging (MRI) techniques can provide...
Recently, radial hybrid magnetic bearings (RHMBs)，which can suspend the rotor stably by electromagnetic forces in radial two degrees of freedom (2-DOF), have received more and more attentions. Besides, RHMBs have the advantages, such as no wear, no lubrication, long life and free maintenance. Therefore, RHMBs have broad application prospects in industrial rotating machineries, especially in...
In this study, we report on the optimized design results of REBCO high-temperature superconducting magnets for 3T whole body MRI. That is, for the REBCO magnet consisting of the main coil, the compensation coil, and the shield coil, an optimized design using an immunogenetic algorithm is carried out with two objective functions of maximizing the magnetic field uniformity in the uniform sphere...
REBaCuO, where RE denotes rare-earth elements, superconducting bulk materials are promising for high performance magnets that can trap large magnetic field in compact space. REBaCuO bulk materials are subjected to electromagnetic force and thermal stress in the devices. The electromagnetic force and thermal stress increase as the bulk size and critical current become larger. Thus improvements...
The application scenario of Hybrid type superconducting fault current limiter (H-SFCL) is the ship DC system. Therefore, the superconducting coil works in low frequency environment. The use of iron core can effectively reduce the tapes consumption, help to reduce the end leakage magnetic field, and reduce the AC loss of the superconducting coil in operation. When designing a superconducting...
To magnetize superconducting bulks in a more cost-efficient way, pulsed-field magnetization (PFM) is a promising method using a conventional solenoid coil on a laboratory scale. The trapped field, BT, by PFM of a ring-shaped bulk reported to date is around 0.3 T at 60 K, which is quite low compared with that of field-cooled magnetization (FCM), as well as disc-shaped bulks by PFM. The reason...
JT-60SA is a tokamak magnetic confinement device for plasma experiments. This is one of a joint international research and development projects involving Japan and Europe. JT-60SA adopts superconducting magnets consist of cable-in-conduit conductors. The magnet system consists of 18 Toroidal Field (TF) coils and 4 Central Solenoid (CS) modules, and 6 Equilibrium Field (EF) coils. Poloidal...
Abstract-Experimental Advanced Superconducting Tokamak (EAST) is the first fully superconducting tokamak in the world. The superconducting magnets are made of NbTi Cable-In-Conduit Conductor (CICC). The heat load due to plasma discharge rises the temperature of magnet. If the cooling of magnet is not sufficient and the temperature margin of the superconductive cables is not enough, it maybe...
Abstract-China Fusion Engineering Test Reactor (CFETR) is the next device in the roadmap for the realization of fusion energy in China, which aims to bridge the gaps between the fusion experimental reactor ITER and the demonstration reactor (DEMO).
The toroidal field (TF) coils play a major part in the tokamak, which provide the main magnetic field to confine the plasma, and one TF coil has...
Abstract: The high-frequency insulated core transformer (ICT) accelerator is expected to replace traditional ICT for its small size and high power density in the field of irradiation below 1MeV. As a key component of the accelerator, the ICT high-voltage power supply is used to feed the accelerator tube. Segmented core structure of the ICT will lead to uneven flux density distribution of...
By using a High-temperature superconducting (HTS) tape, it is possible to realize a coil that can generate much higher magnetic field. However, it is a problem to increase the inductance in an HTS coil since the number of windings increases due to restriction on the current capacity of an HTS tape. For coils with large inductance, large induced voltage and noise are induced between the coil...
The poloidal field coils (PF1 to PF6) of the proposed EUROfusion DEMO machine are to be operated in the pulsed mode. The heat is deposited in these coils due to field changes during a normal plasma cycle, due to field changes corresponding to a range of plasma control actions, due to nuclear heat load, etc. The PF2-PF5 coils winding packs (WP) are made up of the NbTi cable-in-conduit...
Recently, we proposed a novel winding technique, which entails employing grease materials as a turn-to-turn insulator to ameliorate the charging-discharging delay observed in no-insulation (NI) coils. As a result, we obtained coils that possess superior thermal and electrical stabilities without charging-discharging delays. However, because of the higher resistance of these grease materials as...
Implementing an efficient quench protection system in a classical insulated High Temperature Superconductor coil remains complicated and risky. Since about ten years, many groups have been working on novel windings consisting on removing the classical insulation between turns. This solution improves the thermal stability, and it avoids local degradations in case of a quench. One named them as...
In the context of tokamak reactors, the Poloidal Field Coils (PFCs) are magnets that surround the Toroidal Field Coil (TFC) assembly and generate a magnetic field which equilibrates the plasma and shapes it into specific forms. To enforce plasma requirements, the six PFCs of the Divertor Tokamak Test (DTT), a facility that will be built at the ENEA research centre in Frascati with the main...
As a novel type of rail transit system, high temperature superconducting (HTS) maglev has entered the research and development stage of engineering application. During the future practical engineering, the dynamics performance of HTS maglev system is very important. Because its vibration characteristics will affect the safety and comfort of vehicle operation. Although, lots of previous...
JT-60SA (JT-60 Super Advanced) is a full-superconducting tokamak, constructed in Ibaraki Japan. The operation of JT-60SA is being carried out under Japan and European Union broader approach project. The superconducting magnet system of JT-60SA has 18 toroidal field (TF) coils, 4 modules of a central solenoid (CS), and 6 coils of equilibrium field (EF) coils.
The TF coils are D-shaped coils...
The SPARC Toroidal Field Model Coil (TFMC) Project seeks to design, build, and test in a two-year time period a first-in-class, high-field, large-scale fusion magnet using Rare Earth Yttrium Barium Copper Oxide (REBCO) superconductor. The principal objective of the project is to retire the operational and manufacturing risks of REBCO toroidal field magnet technology at-scale for the SPARC...
We have been developing conduction-cooled HTS magnets wound with REBCO-coated conductors for MRI systems, with the aim of developing 9.4 T MRI magnets for whole-body and brain imaging. One of a key technology to implement the REBCO coil is quench protection and we proposed a quench protection method using electrically conductive epoxy resin [1]. The electrically conductive epoxy resin is...
The plasma confinement of the International Tokamak Experimental Rector (ITER) is provided by the magnetic field generated by 18 toroidal field (TF) coils while 6 poloidal field (PF) and 6 central solenoid coils have the function to drive, shape and pre-heat the plasma. Fusion for Energy (F4E), the European Domestic Agency for ITER, is responsible for the supply of 10 TFC and 5 PFC to the ITER...
We are developing a helium-free 3T-MRI high-temperature superconducting magnet for whole-body imaging using REBCO wire. The development of a meter-class REBCO magnet has few practical examples, and the problem in the manufacture has not been clarified. Therefore, we grasped the characteristics of REBCO coils by manufacturing meter-class coils and evaluating the current-voltage characteristics...
In the last few years High Temperature Superconducting (HTS) non- and partially insulated coils have shown exceptional resilience towards quench and other disrupting effects in many practical experiments. These coils are therefore widely investigated as an approach towards larger high field HTS magnets for both Fusion and Particle Accelerator applications. One of the main concerns for these...
QST, as Japan Domestic Agency (JADA) in ITER, has responsibility to procure 9 ITER Toroidal Field (TF) coils and all 19 TF Coil Cases (CC). The 9 TF coils are procured by two suppliers to accelerate their production. In the first supplier, four TF coils have been fabricated and three of them has been delivered to the ITER site. On the other hand, the second supplier fabricates the forth TF...
The innovative concept of using a combination of two identical superconducting bend magnets working at a fixed field in a proton therapy gantry, allows for a light and compact design, while being able to deliver protons over a range of 70-230 MeV. In this concept, the gantry is conceived as achromatic, allowing the magnets to operate at a constant field, and therefore avoiding the technical...
REBCO coated conductors (CCs) are expected to be applied to high field magnets due to their high longitudinal tensile strength and excellent critical current characteristics in high fields. For large scale magnets with large stored energy, the coil design is determined by the feasibility of quench protection. Although various quench protection methods have been proposed for REBCO magnets, the...
The poloidal magnetic field of ITER is provided by 6 Niobium–Titanium (NbTi) coils mainly for plasma shaping and position control. The fabrication of the two lower coils PF6 from China ASIPP and PF5 from European F4E has been completed and the coils installed in the bottom of the Tokamak pit in 2021. This paper presents the challenge of the manufacturing process, which involves manufacturing...
A collaboration between CERN, CNAO, INFN and MedAustron has been formed with the aim at designing a light rotating gantry suitable for hadron therapy based on 430 MeV carbon ion beams. After a preliminary design based on 3 T dipole field, now the collaboration is engaging to improve the design to 4 T or more. The magnets are designed according to cosθ layout to be wound with Nb-Ti...
Growing interest for high-temperature superconducting (HTS) tapes, in particular the 2nd generation with functional layer of REBCO (RE = Y, Gd, Er,…), is motivated by an impressive progress in capability of such conductors to transport large currents. Nevertheless, this essential property, characterized by the value of critical current, Ic, quite often fluctuates along 100-1000 m lengths by...
The use of carbon ions in particle therapy can enhance the treatment quality, introducing higher biological effectiveness compared to photons and protons.
Rotating gantries are nowadays used to deliver particle beams from different directions to obtain precise conformal dose mapping at the tumour location. The mechanical stability requirements during the rotation usually require heavy...
High-temperature superconductors (HTS) are expected to have a major impact on the development of future particle accelerators and fusion energy systems. One of key challenges associated with HTS is a slow propagation of the normal zone that complicates early detection of thermal runaway (quench) in an HTS magnet using voltage-based techniques. Furthermore, fusion systems require field ramping...
The Wendelstein 7-X (W7-X) stellarator equipped with a large cryogenic magnet system (MS) [1] has been extended for the long pulse operation at the Max-Planck-Institute for Plasma Physics in Greifswald, Germany. If the main focus of mechanical engineers during first two experimental campaigns was on the static structural strength of the MS, the issue of component cyclic behavior is addressed...
A Mach-Zehnder Interferometer (MZI) based optical fiber sensing technique developed and patented by EPFL is an efficient and economical way to detect hotspots in HTS applications. Due to the MZI sensitivity being a composite of strain sensitive and temperature sensitive contributions, the MZI gives an instantaneous response to a quench (within 10 ms) resulting from the quick strain transfer to...
The critical heat flux in liquid hydrogen is ten times higher than that in liquid helium, and is approximately half of that in liquid nitrogen. Since the resistivity of pure metal such as copper or silver at 20 K is less than one-hundredth of that at 300 K, HTS magnets immersed in liquid hydrogen are expected to satisfy the cyostable condition at a practical current density for electric power...
One of important application for HTS bulk magnets is compact NMR/MRI. We have developed a single-sided (unilateral) HTS bulk magnet and a home-built NMR spectrometer to get NMR relaxometry signals from the sample on the outside of the magnet. The NMR signal relaxation rate, the only parameter that is observed in NMR relaxometry, still gives us the information about the mobility of molecules,...
The Grenoble Hybrid magnet is a modular platform using resistive and superconducting technologies to produce various DC high magnetic field and flux configurations for the scientific community. They range from 43 T in 34 mm diameter with 24 MW of electrical power to 9 T in 800 mm diameter, when the superconducting coil is used alone. Thanks to the ongoing upgrade of the electrical power...
We report experimental and theoretical results of power generation characteristics of a 1 kW class fully High Temperature Superconducting Induction/Synchronous Generator (HTS-ISG) that consist of a stator winding using REBCO coated conductor and a rotor winding using BSCCO tape.
Recent advances of the HTS material technology make it possible to realize electric machines that show high...
Internal oxidation technique could generate nano oxide particles in Nb3Sn strands, which could significantly refine the Nb3Sn grain size and boost the high-field critical current density. . In this paper, we will report the recent progress of the APC (Artificial Pinning Center) Nb3Sn wire in Hyper Tech. Our APC Nb3Sn wires with Ta and either Zr or Hf doping demonstrated substantial grain...
To extend its user’s facilities the High Field Magnet Laboratory (HFML) of the Radboud University is in the process of building a 45 T hybrid magnet. The magnet system will consist of a 22 MW, 32.7 T Florida-Bitter type of resistive insert and a 600 mm bore, 12.3 T Nb3Sn based CICC type of superconducting outsert magnet. The Nijmegen hybrid magnet will be operated with separate current sources...
In order to improve the current performance of the Large Hadron Collider (HL-LHC project) or to construct the particle accelerators for the Future Circular Collider (FCC), the development of high field Nb3Sn magnets is of high importance. A Heat Treatment (HT) is required for the formation of the Nb3Sn superconducting phase that leads to various physic-chemical phenomena inside the...
The cryogenic and electrical tests of a hundred-kW HTS dynamic synchronous condenser (DSC) prototype were conducted in recent months. The performance of this prototype, which was developed to verify some key technical aspects for the future 10-Mvar HTS DSC, was evaluated based on the test results. The active power test results were nearly the same with design values, which indicated that the...
A no-insulation (NI) high-temperature superconductor (HTS) winding technique has been mainly applied to direct-current (DC) high field magnets, while its application to alternative-current (AC) machines is limited. One of the potential applications of the NI HTS winding technique is a synchronous rotating machine, typically employed in aircraft and ship electric propulsion. Under an ideal...
In the quest for all-superconducting very high field magnets, the first successes where obtained with High Temperature Superconducting inserts wound using BiSrCaCuO conductors. It is the case for the 25T CSM (Cryogen-free Superconducting Magnet) installed in 2015 at the HFLSM (High Field Lab. for Superconducting Materials). It remains to date the only magnet above 24T that is fully open to...
Recently, we have reported successful fabrications of the Jelly-Rolled Nb/Al composite monofilament wires having 50 microns in outer diameter. Those Nb3Al super-fine wires show a ductile mechanical performance and may be promising to apply for the React and Wind high field superconducting magnets. However, those Cu/non-Cu ratio was 0.5. So far in our study, it has not been succeeded to draw...
Recent developments in low ac loss MgB2 conductors are of significant interest, given revived interest in fully superconducting (SC) generators. Evaluating AC losses in SC armature windings is critical to develop a feasible fully SC machine. In fully SC machines, SC armature windings experience rotating magnetic fields with spatial and time harmonics which has an undisputed impact on ac...
Nb3Sn superconducting wires made by the restacked-rod process (RRP®) exhibit a precipitous change of their intrinsic irreversible strain limit εirr,0 with heat-treatment temperature , called the strain irreversibility cliff (SIC). The occurrence of SIC over a very narrow range of , within the domain of temperatures typically used for heat-treating magnets made of RRP® wires, can be a...
In the continuity of the Large Hadron Collider (LHC) large-scale projects are under development, such as the HiLumi - LHC and the Future Circular Collider (FCC), in order to produce particle collisions at higher luminosities and energies. The achievement of these projects strongly relies on the development of high field Nb3Sn magnets. The Nb3Sn intermetallic superconducting phase is produced...
A large-bore Nb3Sn “cable test facility magnet” designed to test advanced cables and inserts in a high transverse background field, is here proposed. The project is funded by the U.S. Department of Energy (DOE) Office of Science (SC). The test facility dipole magnet (TFD) creating the background field is developed at the Lawrence Berkeley National Laboratory (LBNL). In line with the...
The properties of high-temperature superconductors (HTS) have inspired several applications in electric power systems. In particular, their zero resistance and high current capacity can lead to more compact and efficient generator designs.
Despite its zero resistance, HTS experiences losses under time-changing current or magnetic fields. These losses are fundamental during the design of...
The DEMO ENEA Low Field W&R (Wind and React) conductor, developed in the frame of the conceptual design studies for the Toroidal Field (TF) coils of DEMO, has been designed to be constituted of a small number of superconducting Nb3Sn strands and a high number of stabilization copper wires. It has been extensively characterized at the SULTAN facility in February 2021. The conductor has been...
A 35 T/17 mm cold-bore full superconducting magnet has been designed. It consists of a 15 T LTS background magnet with the inner radius of 150 mm, and a 20 T HTS insert magnet with the inner radius of 17 mm. We hybrid used no-insulated and steel-insulated REBCO tapes to wind the HTS insert, with the aim of protecting part of HTS coils in a relatively safe state. Two mechanical models were...
A 25 T All YBCO superconducting magnet with a warm bore of 52mm is designed for high-frequency gyrotrons in Wuhan National High Magnetic Field Center (WHMFC). The designed peak-peak field inhomogeneity is 50 ppm within 10mm Diameter of Spherical Volume (DSV). The magnet includes Inner, middle and Outer Coils which consists of 34, 56 and 68 double pancakes (DP) wound by bare YBCO tape,...
Our group has successfully developed SCML-03, which was used to study the dynamic behavior of high temperature superconducting (HTS) maglev. As the experimental speed of SCML-03 can only reach 300 km/h, it is no longer competent for research tasks in a higher speed range. At present, HTS maglev has entered the key stage of engineering application. In order to study its dynamic characteristics...
AC loss in the Nb3Sn cable-in-conduit conductors (CICC) usually decreases after the conductor undergoes electromagnetic cycling. This can be attributed to the increase of inter-strand resistance due to strand-bonding detachment during cyclic loading. In the years 2018 to 2020, ITER launched a series of test campaigns in SULTAN test facility, whose aim was to study the Tcs degradation of TF...
In 2015, we achieved 24.6 T by the 25T cryogen-free superconducting magnet (CSM) with a Bi2223 insert. Then it has been used as a user magnet at High Field Laboratory for Superconducting Materials, IMR, Tohoku University. The Bi2223 insert consists of 38 double pancake coils with high strength Ni-alloy/ Bi2223 tapes (Sumitomo type HT-Nx) [1]. In this case, we used turn separation in the middle...
Abstract: The High temperature superconducting flywheel system for energy storage is attractive due to its self-stable levitation of the rotor without control and a great reduction in the rotational loss of the bearings. It can improves the energy storage capacity and density of single machine, and will have broad application prospect in the future. This paper presents the recent progress on...
Cuprate high-temperature superconductors (HTS), such as RE-Ba2Cu3O7-d (REBCO, RE=rare earth) coated conductors, (Bi,Pb)2Sr2Ca2Cu3O10-x tapes and Bi2Sr2CaCu2O8-x wires, have enabled the development of high-field superconducting magnets. The brittle nature of HTS requires elaborate means to protect them against the high stresses associated with high-field magnet operation, which so far have...
In the framework of the US Magnet Development Program (MDP), Fermilab has developed and tested a high-field Nb3Sn dipole demonstrator MDPCT1 for a post-LHC Hadron Collider with the goal to achieve the field of 15 T in the aperture. The magnet design is based on 60-mm aperture 4-layer shell-type coils, graded between the inner and outer layers to maximize the magnet performance. An innovative...
Superconducting magnets are employed in accelerators to achieve higher magnetic fields to attain a higher particle-beam deflection. However, superconductivity, i.e. the complete absence of electrical resistivity, is lost upon exceeding a critical temperature leading to the quench phenomenon. Then, the affected magnet regions shift to normal-conducting state and begin to heat up. In the worst...
The R&D project of compact high-temperature superconducting (HTS) cyclotron system for radioisotope production is ongoing, supported by Japan Science and Technology Agency (JST) and Japan Society of the Promotion of Science (JSPS). This HTS cyclotron has two major features: (1) the magnet has no iron core (air-core), and (2) the output energy is variable. The developing HTS cyclotron system is...
MDPCT1 is a four-layer cos-theta Nb3Sn dipole demonstrator developed and tested at Fermilab in the framework of the U.S. Magnet Development Program. The magnet reached record fields for accelerator magnets of 14.1 T at 4.5 K in the first test and 14.5 T at 1.9 K in the second test and then showed large degradation. While its inner coils performed exceptionally well with only two quenches up to...
Superconducting magnets designed for high energy physics and nuclear fusion require mechanical stabilization and electrical insulation to perform at high currents and magnetic fields. Vacuum pressure impregnation (VPI), a process of curing epoxy in and around the superconducting wires, is most commonly used to support and consolidate a magnet. However, the heat and mechanical stresses...
High-field REBCO magnets contain several pancake coils with many turns, which are vulnerable to high stress and strain due to the large background magnetic fields. In addition, screening currents substantially increase the stress. Electro-thermal quench is another issue which is required to be taken into account while designing a high field magnet. Thus, there is a need for fast and accurate...
High current Rare-Earth Barium-Copper Oxides High Temperature Superconductor (HTS) Cable-In-Conduit (CIC) Conductor conceived for large fusion magnet applications based on aluminum slotted-core incorporating HTS tape stacks has been successfully proposed in the last years [1]. In this work, the activity carried out for designing and manufacturing CIC samples aimed at the investigations of...
As the high critical current at high field, the representative second-generation high-temperature superconductor (2G HTS) ReBCO serves as a good candidate for future fusion devices, i.e. the Chinese fusion engineering test reactor (CFETR), the Demonstration Power Station (DEMO) with magnet field higher than 15T. The main goal of CFETR is to build a fusion engineering tokamak reactor with a...
A 46 T all-superconducting magnet is being designed at the Institute of Plasma Physics Chinese Academy of Sciences. This magnet consists of, from the outside to the inside, the CFETR CS model coil capable of producing a 10 T central field, a REBCO-CORC insert coil providing an additional 10 T central field, and three REBCO insert coils which are dry wound with 4 mm wide REBa2Cu3O7-x tape...
After more than 20 years of development, the manufacturing of high-temperature superconducting (2G-HTS) wire has been quite well established: a thin (1-2 microns) layer of YBCO superconductor epitaxially deposited on a biaxially aligned metal substrate. Such a conductor is very susceptible to current blocking defects. These defects are typically caused by mishandling of the tape between the...
The accelerator Nuclotron is one of the most important installations of the NICA accelerator complex in Dubna, which also includes a booster synchrotron and a collider. The superconducting booster synchrotron was put into operation at the end of 2020, the superconducting collider is in the final stage of assembly. Its launch is scheduled for late 2022. The magnetic system of the...
The quench process in a superconducting magnet is inherently transient and three-dimensional (3D). In many cases, such as magnets protected by active protection systems, it is possible to accurately simulate this transient with a two-dimensional model. However, a more complex 3D model is required in case of a self-protecting magnet. Simulations are particularly challenging due to physical and...
We have succeeded in measuring critical current, Ic, in multi-filamentally Bi-2223 tapes at extremely low electric-field criterion down to at around 10^-13 V/m, at 5 K and external magnetic fields up to 4.5 T perpendicular to the tape surface which is comparable to the operation condition of Bi-2223 based insert magnet for 30 T-class NMR magnet in persistent mode operation. While the Ic of the...
Commercial REBCO tapes are a promising technology for power and magnet engineering. Due to their complex manufacturing, they present inhomogeneities of the critical current distribution and silver stabilizer thickness along their length. It is therefore paramount to investigate the impact of inhomogeneities when designing superconducting devices based on such tapes.
This kind of study...
The High Intensity Heavy-ion Accelerator Facility (HIAF) is a new project under construction in China, which will provide beams of stable and unstable heavy ions with high energies, high intensities and high quality. This paper discusses the superconducting magnet system for this accelerator complexes. It will consist of a Nb3Sn magnet with the peak field of 12 Tesla for the ECR ion source...
MgB$_2$ superconducting wires hold the advantage over traditional NbTi wires of higher temperature operation, at lower cost than REBCO tapes, and allowing the use of existing winding techniques. The adoption of MgB$_2$ wires into large-scale applications such as MRI solenoid magnets, long-length power cables, wind turbine generators or industrial magnets requires a robust production process...
With only 1 µm thickness of high temperature superconducting (HTS) material, HTS tapes are very fragile and can easily undergo an irreversible damage when operated near to its rated values. When wound into coils, this phenomena intensifies, limiting the operating values to only 50-80 % of its rated values. This is mainly due to the restricted HTS current path and poor thermal conduction...
An asymmetric dependence of the critical current on the direction of an applied magnetic field in HTS coated conductors has a non-trivial influence on the AC loss of coil windings. We report the modelled influence of real conductor critical current asymmetry on the AC loss characteristics of a 1 MVA HTS transformer design previously demonstrated by the Robinson Research Institute as well as a...
It is required to improve yield of coiling for REBCO-based magnet developments, however, the conventional test method represented by the end-to-end current transport measurement of the coil could not derive detailed information such as the positions of the defects and the mechanisms for the failures. In this study, we have developed a novel method adopting hybrid microscopy integrating...
Renewable energy and electric power liberalization have become important watchwords for present electric power system. However, the stability of electric power systems is also a serious concern because of the lack of inertial energy of conventional synchronous generators. Since a low system stability may cause an unexpected power oscillation with the natural frequency of an electric power...
JT-60SA is a superconducting tokamak constructed in a project being undertaken jointly by Japan and Europe. The thermal shield provides screening of the superconducting coils from the plasma vacuum vessel at elevated temperature and the tokamak cryostat at ambient temperatures. The thermal shield is made of stainless steel plates and is cooled by helium gas which flows in embedded pipes along...
We have been developing DC superconducting cable with magnetic energy storage function. This novel application offers high-speed and high-power charge/discharge operation indispensable for compensating output power fluctuation from renewable energy sources such as photovoltaic, wind turbine, etc. In this paper, we will report its development status under a Japanese national program: (1)...
We present a systematic design approach to the cryogenic system of ReBCO coated conductor based high-temperature superconducting actuators used in highly dynamic applications. While ReBCO coils operating around 20 K can in principle increase the force-density of linear actuators by nearly a decade, the thermal design of such a system poses two important challenges. First, the foreseen AC loss...
High temperature superconducting (HTS) magnets working as inserts inside low temperature superconducting (LTS) magnets are foreseen to enable >16 T class accelerator dipoles for future particle colliders. Under the U.S. Magnet Development Program (US-MDP), LBNL has been making steady progress towards designing and fabricating practical Bi-2212 and Nb3Sn canted-cosine-theta (CCT) dipoles that...
A project to develop a 10-Mvar high temperature-superconducting (HTS) dynamic synchronous condenser is carried out by China Southern Power Grid Corporation. In order to cool the magnets to 20-30 K, a set of cryogenic system using circulating helium as the working fluid was developed, and it has been coupled and tested with the 10-Mvar class dynamic synchronous condenser. Six cryogenic coolers...
The U.S. Magnet Development Program (US-MDP) aims at developing high-field accelerator magnets with magnetic fields beyond the limits of Nb3Sn technology. Recent progress with composite wires and Rutherford cables based on high temperature superconductor Bi2Sr2CaCu2O8-x (Bi2212) allows considering them for this purpose. However, Bi2212 wires and cables are sensitive to transverse stresses and...
A power supply system with transformer type superconducting magnetic energy storage (SMES) is being created to power the superconducting magnets of the particle accelerators Booster and Nuclotron of the NICA complex at JINR. The system includes a solenoid made of HTS cable, with an operating temperature of 28 K, with flow cooling by liquid neon, and an operating current of up to 8 kA with 4 s...
Magnetised bulk superconductors can be used as super-strength, stable permanent magnet analogues capable of providing magnetic fields of several tesla in a compact and portable magnet system. In addition to a large magnetic field, B, the magnetic field gradients (dB/dz, dB/dr) are naturally large. This makes them attractive for a number of engineering applications that rely on high magnetic...
Recent development of Bi-2212 insert coil technology at National High Magnetic Field Laboratory (NHMFL) has shown promising in-field performance, ~ 440 A/mm2 at 16.3 T peak field in 2019, thanks to the matured conductor technology and reliable heat treatment process. Now Bi-2212 coil technology is entering to a new stage to be considered as a competitive candidate for high field (above 20 T)...
The article presents the results of the preliminary development of the HTS conductor based on the VS-type design for the central solenoid of the compact thermonuclear reactor TRT, which is under development in Russia. The operating current of the conductor have to be at least 60.0 kA in the field of 15 T at temperatures of 5-20 K. The compactness of the magnetic system requires the creation of...
Only a handful of high-temperature superconducting (HTS) electric machines using HTS bulks as magnetic poles have been developed. This is mostly due to the need for the bulks to be magnetized before use, which is a challenge for practical application. It is important to develop a magnetization method for the bulk arrays because recently we have used them as an armature for high power...
BaFe2As2 (Ba122) shows high upper critical field (Hc2 > 50 T) with small electromagnetic anisotropy (γ ~ 1-2) [1] and large critical grain boundary angle (θc ~9˚) [2], and therefore is a promising material for applications in polycrystalline form. Foreseeing high field magnet applications, Weiss et al. have reported demonstration of trapped field of 1 T for K-doped Ba122 polycrystalline bulks...
Railway Technical Research Institute is researching the magnet technology on the application of the railway system.
In magnet technology, we are fabricating and evaluating magnetic materials. As applications of magnet, we are developing research on the high-temperature superconducting magnets, the superconducting magnetic energy storage, the superconducting traction transformer, the...
