The Z pulsed power driver at Sandia National Laboratories is used for a wide range of high energy density physics experiments in areas such as inertial confinement fusion, radiation effects, and dynamic material properties. Experimental demands are pushing for the highest energy attainable with more reliability and precision in timing and pulse compression. A previous version of the...
Unusual electrodynamic properties of metamaterials naturally call for investigations of their applicability as slow wave structure (SWS) elements in modern microwave vacuum electron devices [1,2]. In this work, a novel microwave oscillator based on the idea of a cylindrical metamaterial SWS (MSWS) is designed. The designed MSWS, consisting of split ring resonators (SRRs) with oppositely...
Water can be activated by applying plasma in contact with the water. Plasma activated water (PAW) typically contains hydrogen peroxide, nitrates, nitrites, and peroxynitrite, and typically has a pH ranging from 2-4.The components of PAW and the low pH have proven synergistic antimicrobial effects against bacteria, biofilms, yeasts and other microorganisms.
In this contribution, we describe a...
Backward Wave Oscillators (BWO’s) utilizing moderately relativistic (~500kV), high-current (~10 kA) electron beams are capable of producing hundreds of MWs of pulsed radiation in the centimeter wavelength range. Such relativistic BWOs (RBWOs) allow for relatively broadband, smooth, frequency-tuning via adjustment of the accelerating potential; making them an attractive source for use in...
This study focuses on achieving wide tunabiltiy of a compact reflex triode virtual cathode oscillator (vircator). The cathode is of a bimodal carbon fiber (CF) material paired with a pyrolytic graphite anode. These materials display ideal operating characteristics which including but not limited to, long lifetime > 10^6 shots, high operating temperatures > 1000 K, and large current densities...
Water purification technology that can decompose refractory organic compounds efficiently is required because eluent standard of factories became stricter. As one of methods of water purification, we have studied spraying polluted water into pulsed discharge. In this method, polluted water is purified by OH radical and ozone mainly, which are produced by the discharge. However, generation...
Propylene carbonate (PC) is a promising dielectric for the compact pulsed power sources because of its large permittivity, high dielectric strength and broad operating temperature range. By adding nano-particle suspensions homogeneously to the dielectric liquid, the insulating properties of the dielectric liquid can largely be enhanced in the electrical engineering application. In this paper,...
An Exploding Foil Initiator (EFI) is one method used to detonate secondary high-explosives without the use of sensitive, primary high-explosives.
We are developing a new, high-energy EFI system (also known as an E-gun) to replace and enhance an existing E-gun that is near its end of life. The existing E-gun stores 48 kJ at 40 kV and has been used at currents up to 1 MA. The new system will...
Persistent organic pollutants, such as pharmaceutical residues, often withstand treatment by conventional water treatments. Plasmas generated directly in water have shown to effectively decompose these compounds, presenting a promising new approach. Especially corona-discharges that are generated by short high voltage pulses are able to penetrate large volumes of water of different...
The transparent cathode is a cathode in which separate longitudinal emitters are periodically placed about a fixed radius from the center [1]. Owing to the longitudinal current along each emitter there is a periodic azimuthal magnetic field in which electrons drift in an applied radial electric and longitudinal DC magnetic field. Thus, this cathode in a smooth-walled tube operates as an...
Thyristors of tablet design with diameters of silicon wafers of 40 to 56 mm and an operating vol-tage of 2 to 2.4 kV DC were triggered by an external overvoltage pulse applied across the thyris-tor main electrodes. In experiments a voltage rise rate across the thyristor was changed from 1 to 6 kV/ns. Under such conditions the thyristor closing process occurred due to initiation and...
A high power inverted relativistic magnetron was designed and simulated using the massively parallel electromagnetic particle-in-cell code ICEPIC in conjunction with single particle smooth bore relativistic analysis. This Inverted Magnetron also known as the Inverted Magnetron Oscillator (IMO) has two design variations, the IMO-1 and the IMO-2. Both IMO models are designed to operate in L-band...
For discrete semiconductor switches with smaller ratings stacked for high-voltage high-current applications, there is the need to ensure reliable gate synchronization of all the switches in the stack. The delay of switching of separate stages must be minimized by reducing the effects of stray inductances in the switch operation. This paper describes the design of a HV switch for high-voltage,...
The global water environment continues to worsen mainly due to organic pollution caused by agricultural and domestic and industrial wastewater. Wastewater includes many kinds of pollutants. Among them, persistent organic pollutants (POPs) present serious problems due to their high environmental persistence and hormone-like activation. Further, they are resistant to environmental degradation...
In the process of treating tumor with nanosecond pulsed electric fields, the muscle contraction is inevitable. The purpose of this paper was to study the effect of different parameters of high frequency nanosecond pulse bursts on the rabbit muscle contraction strength. Ten unipolar high frequency pulse bursts with different field intensities (3 kV/cm, 5 kV/cm and 10 kV/cm), intra-burst...
A 50 kV solid-state switch has been developed using ThinpakTM Current Controlled SolidTRON® (CCS) thyristors from Silicon Power Corporation. A switch comprises thirty-six, series-connected thyristors and an internally powered, optically initiated trigger circuit. The trigger circuit drives the common primary winding of sixteen trigger transformer; each transformer has two output windings...
Under the sponsorship of the Joint Non-Lethal Weapons Directorate (JNLWD), the Directed Energy Warfare Office (DEWO) at the Naval Surface Warfare Center (NSWC) Dahlgren Division has completed refurbishment of the Orion high-power radio-frequency (HPRF) system to support RF vulnerability testing. Orion is a flexible HPM source allowing for frequency agility from 1.07 GHz up to 3.3 GHz with...
Pulsed electric fields (PEF) can cause irreversible damage to the bio-membranes of microorganisms, with the resulting electro-mechanical stresses induced across their membranes stretching and potentially rupturing these phospholipid bi-layers. The electro-mechanical stresses have an electrostrictional nature, as the membrane the cytoplasm inside the membrane and the external suspension have...
Diversified Technologies, Inc. has introduced a new PEF (Pulsed Electric Field) system for processing fruits and vegetables by softening their tissue at the cellular level which makes slicing, dicing, peeling, drying, and juicing easier.
Diversified Technologies' PEF System for the tissue modification of fruits and vegetables lowers their processing cost by actually making more of the cell...
With the availability of very high power (~$10^{9}$ W) and short duration (≤$10^{-9}$ s) microwave sources it is possible to study the non-linear interaction of powerful EM waves with under dense plasmas in a regime not studied so far. In contrast to the laser-plasma wakefield experiments, this approach addresses a significantly lower power, plasma density and electric field gradient regime...
The high energy density (HED) capacitor is the energy storage component in capacitive pulsed power systems. There is an obvious voltage decay phenomena when the capacitor is disconnected with the charge source, and the higher the energy density is, the faster the voltage decay. And the voltage maintaining performance (VMP) of capacitor is of special interests especially in the occasion that...
Atmospheric-pressure plasma jets have recently received significant attention due to its unique capabilities as low temperature, low cost, portability, and ease of operation which are suitable to such novel applications as analytical chemistry, thin film processing, nanomaterial synthesis, surface modification, sterilization, and etching. In biological applications, chemical species including...
Abstract: Experimental results of an L band all cavity axial extraction relativistic magnetron (RM) working at 1.57 GHz is presented. In this 6-cavity RM configuration, the microwave from two adjacent cavities is coupled into an axially oriented coaxial sector waveguide through radial slots on the cavities. This configuration is more compact because only three sector waveguides are added...
A comprehensive picture of the relationship between optical fluence $(30-30,000~\mu J/cm^2)$, optical wavelength $(295-375~nm)$, electrical bias $(8-64~kV/cm)$, and photocurrent efficiency (defined as the ratio of electrons extracted to electrons generated) in SiC photoconductive semiconductor switches (PCSSs) is presented. The behavior of SiC PCSSs including high electric field stress...
Cygnus, a dual-beam x-ray source, supports the Subcritical Experiments Program at the Nevada National Security Site for both Los Alamos and Livermore National laboratories. Since 2004, Cygnus has been successfully fired over 3000 times and refurbishment activities were completed in 2012 and 2016. The major refurbishment in 2016, conducted over a six-month period, will rejuvenate Cygnus...
Eagle Harbor Technologies, Inc. (EHT) has developed a 35 kV pulser for driving 50 Ω loads with nanosecond-scale rise times. This inductive adder uses EHT’s nanosecond pulser technology to drive nonlinear transmission lines (NLTL) to construct an all-solid-state RF plasma heating system for fusion science applications. The inductive adder configuration allows for independently adjustable...
At present, the infrastructure of China Spallation Neutron Source (CSNS) project is finished in Dongguan city, Guangdong province of south China. Now the system debugging is under way. CSNS accelerator consists of an H- linac and a proton rapid cycling synchrotron. The 324MHz RF linac is designed with beam energy of 81MeV and a peak current of 30mA, which mainly includes one RF Quadrupole...
This paper presents a new type of equivalent circuit of a high-voltage pulse transformer and an accurate method to measure it’s parameters. The new equivalent circuit is obtained from the impedance characteristic curves when the primary and secondary coils are in different states (open circuit or short circuit). In the new equivalent circuit, the distributed capacitance between primary and...
This paper proposes a dual-line closed transition transfer switch (CTTS) and a technique for fault and lifetime self-diagnosis. The proposed system consists of the dual-line CTTS, a closed transition operator, active and inactive channel inspectors that extract the switch characteristics, and a self-diagnosis block for fault and lifetime of the switch using the characteristics. The system...
A prototype S-band sheet beam klystron has been fabricated and tested. To enable testing of this one of a kind tube, a unique test stand was created that we will discuss in this presentation. The sheet beam klystron was designed to operate at 2.856 GHz and nominally produce 6 MW peak / 6 kW average r.f. power. A ScandiNova solid state modulator delivers the high voltage pulse to the potted...
Abstract: The two-way power combiner consisting of two TM01-TE11 serpentine mode converters with a common output has demonstrated high power capacity and high combination efficiency for two phase-locked relativistic backward wave oscillators (RBWOs) [1]. To realize channel power combination for four phase-locked X-band RBWOs, we propose an all circular waveguide four-way power combiner based...
Industrial pollutants and in particular pharmaceutical residues have caused large-scale pollution to the potable water in China. Many pharmaceuticals and macromolecular organic matter withstand conventional water treatment technologies. Consequently, advanced oxidation processes (AOP), and especially low-temperature plasmas with their ability to create reactive species including the hydroxyl...
The BEEMP laboratory in NUDT is now undertaking the research of a promising electric propulsion concept——the pulsed inductive thrusters (PIT). An experimental facility has been set up including a specially-optimized driving coil, a high-voltage pulsed circuit, and a constant-current high-voltage power supply. This paper introduces the design of the experimental facility with special emphasize...
In the sequential discharge of the pulsed power modules connected in parallel, the occurence of a surge voltage at the crowbar diodes of the triggered modules afterward is analyzed and the elimination method of the surge voltage is suggested. In the case using two 100 kJ pulsed power modules and the muzzle-shorted railgun as a load, the surge voltage is generated during the crowbarring period...
The effective treatment of the industrial wastewater is very significant to the protection of our environment. The system of wastewater treatment based on pulsed discharge plasma provides a new way for the disposal of industrial wastewater. However, the traditional reactor cannot meet the demand of degradation rate and the treatment efficiency. In order to improve the degradation rate and...
The coupling path of high power electromagnetic (HPEM) to electronic devices is divided into following two ways, one is the Front-door coupling and the other is the Back-door coupling1. The former is flow in an intended path such as antennas or sensors and the latter is inflow through an unintended path such as holes or cables. As HPEM pulse has higher power and it causes larger damage to...
The application of High-Power Electromagnetic Pulses (HPEMP) in dressing of resistant gold- containing ores appears attractive as this technique provides for a significant increase in precious metal recovery in hydrometallurgical (gold and silver) and gravitational (PGM) processes (V.A.Chanturiya et al, Pulsed Power Conference, 2005 IEEE). The present work studies the effect of high-voltage...
The dynamical behavior of plasmas is strongly dependent on frequency. At the lowest frequency the plasma is in the regime of magnetohydrodynamics (MHD) and has been the focus of extensive research in fluid plasma modeling in the past few decades. At somewhat higher frequencies, the electrons and ions can move relative to each other, behaving like two charge separated, interpenetrating fluids....
Discharge plasma in liquid is generated by high voltage such as 15 kV. Our previous experiments succeed with around 3 kV in under water discharges. Our work aim to generate the discharge plasma in liquid less than 3 kV using capacitor discharges. Electrical capacitance is as follows for discharge: 0.5 µF, 1.0 µF of film capacitor and 4 nF of ceramic capacitor. A charger is used DC power supply...
The tanks and armor vehicles can be damaged by high-speed metal jet caused by the High Explosive Anti-Tank (HEAT). In order to improve the effective length and the penetration capacity of the metal jet, the electromagnetic enhancing system for the metal jet is put forward. Aiming to the effect of the time sequence to the performance of the metal jet, the relationship between the times of the...
To further the goal of optimized material design for pulsed power components, we aim to achieve a fundamental understanding of the model non linear dielectric material BaTiO3, through concurrent experimental and theoretical study. This effort is intended to lead to improved synthesis and design control, and a validated model to enable material predictions difficult to obtain in controlled...
K. Rainwater, D.H. Barnett, J. C. Dickens, A. Neuber and J. J. Mankowski Center for Pulsed Power and Power Electronics Dept. of Electrical and Computer Engineering Texas Tech University, Lubbock, TX, USA
This paper presents the electrical and mechanical hardware considerations of a compact, 160 J modular pulse forming...
Underwater discharges are applied in industrial fields. However, phenomena of underwater discharges have not been completely clarified. The purpose of our study is to clarify characteristics of underwater discharges. In high repetitive underwater discharges, bubbles generated by discharges are gathered to the tip of an electrode. Discharge plasma forms under the influence of the bubbles may...
This paper describes the results of an experimental investigation carried out to compare the contamination performance and surface degradation of outdoor insulators made from different polymeric materials. The tested insulators included silicone rubber (SR), ethylene propylene diene monomer (EPDM) and high-density polyethylene (HPDE), which were used for reference. To replicate typical harsh...
The Dual Beam Radiographic Facility (aka Cygnus) has been operating successfully for over 10 years providing invaluable data for our nation’s stockpile mission. However successful, there have been some failures that may have been predicted, hence eradicated, during an uninterrupted operation phase. This report describes a statistical method to incorporate existing machine diagnostics, such as...
During the last three years, a programme of research into studying the lightning impact on a high peak mountain tower has been undertaken at the SIAME Laboratory. Various diagnostics equipment has been mounted near the tower, such as fast speed cameras to capture the arc propagation and capacitive antennas for electric field measurement.
The present paper presents the design and calibration of...
Electromagnetic launchers with pulse power have an advantage over the chemical guns in that they has the ability to use electromagnetic force to accelerate armature to high velocity. A multi-stage induction type coilgun system is one of the most important research items. Especially, the capacitor driven induction coilgun, which is almost free from physical contact between the barrels and...
Pulsed plasma thrusters (PPTs) are relatively mature electric propulsion devices for small/micro satellites to complete specific space missions. PPTs are mainly divided into two categories, electromagnetic PPTs and electrothermal PPTs. Under the effect of a current pulse, propellant is ablated and decomposed to form plasma bulk. Afterwards, charged particles are accelerated by Lorentz force or...
The capacitor bank topology with a load side crowbar diode is well known as a pulsed power system for the electromagnetic launcher such as coilgun and railgun because of its controllability, reliability, technical maturity. In general case of multi-stages synchronous induction coilgun accelerates a projectile using the electromagnetic force that converts electrical energy to kinetic energy;...
High current facilities have been used for a wide variety of HEDP experiments, such as fusion energy, radiation-physics, equation-of-state, plasma-physics and astrophysics etc. Linear transformer driver (LTD) is a new technical approach that can deliver fast high current and high voltage pulses with very compact devices. One of the most difficult technical problems encountered in building...
A 400 kV - 85 ns PFN-Marx has been developed. Based on an innovative design [1], named the “zigzag design”, the 16 stages of this generator, which delivers an open circuit output voltage of 720 kV, fit in a 650 mm length. For a slightly overmatched load (Zload = 100 Ohm), the output voltage reaches 400 kV with a rise time as less as 5ns. The inductance reduction associated to the innovative...
A switch module assembly utilizing a power crowbar circuit and high-pressure plasma closing switch technology has been designed, constructed and tested. The switch module is the central block of a lightning impulse current generator under development, capable of producing a 10/350μs waveform at a peak magnitude in excess of 200kA (W/R = 10MJ/Ω). The circuit consists of two separately charged...
A pulsed power system based on a coaxial switched oscillator was built and tested. The switched oscillator is charged to over 100 kV either by a Marx generator or a PZT-based autonomous power supply. When coupled to a helical antenna, the system generates electromagnetic radiation with a frequency bandwidth centred on 500 MHz.
Pulse power generators have been used in various fields such as environment, biology, agriculture and so on. Therefore, many researchers demand functions such as high power, short pulse, safety, miniaturization, low cost and ease of use. Our research aim to develop a high performance pulse power generator. The generator has ease of use and miniaturization. It is able to output various trigger...
In this contribution we show results of direct and indirect removal of nitric oxide (NO) with (sub)nanosecond pulses. The nanosecond pulse source is the 0.5-10-ns, 0-50-kV (positive and negative), 0.2-ns rise time pulse source that we recently developed at Eindhoven University of Technology. The direct-removal setup is an in-plasma removal setup, where the polluted air (with NO) is flushed...
Virtual cathode oscillator is a device that generates high power microwaves using oscillation of virtual cathode formed behind the anode. Virtual cathode oscillator has been studied due to its simple structure and tunability. Most virtual cathode oscillator system consists of prime power, pulsed power, microwave source, and antenna. In virtual cathode oscillator, pulsed power system produces...
Power cables are exposed to various stresses in their service lifetime due to loading and transient effects that appear in the system. These stresses degrade the insulation in the long term and can even result in premature failure depending on the severity of the deterioration. Electrical treeing is closely related with partial discharge (PD) and in some stages of its growth it can be...
**This paper presents experimental results from a repetitive pulse HPM-system, consisting of a marx-generator driving a coaxial vircator under high vacuum. The experiments were performed at starting vacuum levels in the high-vacuum range at pressure levels of safe operation for the system. Data was monitored of the vircator voltages and currents from the driving pulse generator, the vacuum...
Pulsed power has long been used in many applications such as ozonizers, sterilization, and bioelectrics; the use of embedded systems for pulse power has been researched. However, certain factors such as the embedded system design make development difficult and complicate system use. Additionally, many fields require certain functions, safety that has noise protection and ease of...
Abstract：The essential launching characteristics of four typical electromagnetic railguns models were comparatively reviewed referring to the current distribution in conductors. Such four models were as a small conductive simple railgun, the large resistive simple one, the large conductive simple one, and the large conductive complex one. First, according to strict physical theories, a small...
In the report we present new approach where radiation phase of Ka-band BWO is controlled by an external rf signal which is ultra-short. Thus, such excitation is not an amplification regime. Particle-in-cell simulation demonstrated that phase-induced BWO excitation is feasible for a seed power minimized to -38 dB with respect to the driven BWO.
In experiments, two synchronized accelerators...
High power microwave sources play a significant role in a variety of applications such as accelerators, basic physics, astronomy, high power radar, thermonuclear fusion, and various industrial applications. The virtual cathode oscillator (vircator) is one of the most promising high-power microwave sources among several types of pulsed high power microwave generators. The vircator is considered...
This article is dedicated to the 100th anniversary of operation of the first main water pipeline in Azerbaijan, named “Schollar-Baku”, designed in 1917 by English engineer William Lindley, provided to this day Baku by clean drinking water. In recent years, due to the depletion of resources, violation of ecological balance on the planet, climate change, etc., pays great attention to development...
We have developed two advanced designs of a field-distortion air-insulated spark-gap switch that reduce the size of a linear-transformer-driver (LTD) brick. Both designs operate at 200 kV and a peak current of ~50 kA. At these parameters, both achieve a jitter of less than 2 ns and a prefire rate of ~0.1% over 5000 shots. We have reduced the number of switch parts and assembly steps, which has...
Design considerations and initial static charge and transient discharge simulations using COMSOL Multiphysics™ are presented for a stacked set of pulse-forming transmission (T-) line modules charged in parallel and discharged in series. Each module is designed to use a rigid injection-molded dielectric (cast in halves to accommodate the center conductor) with a helical discharge path of...
Traditionally, large-amplitude, fast-rising currents and magnetic fields has been measured with electro-magnetic probes such as Rogowski coils or B-dot probes. Such probes are observed to work satisfactorily for many experimental configurations but the probe to digitizer signal is affected by cabling and cabling elements. Measurements must frequently be made in the presence of significant...
Nonlinear Transmission lines (NLTLs) have been studied for high power RF generation with good prospects of applications in pulsed radar systems, disruption of communications in battlefield, etc. Usually, NLTLs employ barium titanate (BT) ceramic-based capacitors or ferrite bead inductor as nonlinear elements, denominated as capacitive or inductive lines, respectively. On the other hand, a...
For production of stable protectors against thermal and chemical influence, we introduce the technology of their spraying on technological surface. Everybody knows that metallic compounds are combustible. This fuel produces the flame of plasma. The processes of oxidation, which take place of burning chamber, are directed to the creation of ideal mixtures for oxy-ionic gases. In the gaseous...
Test stand complex for the testing of land and aerial based HPM sources is described. The stand utilizes low-inductance Marx generator operating in the repetitive burst regime with a rate 1-20 pulses/sec and total energy in pulse of 3kJ/pulse at 7Ohm load. Marx generator produces pulses with the risetime of 10-12 ns, output voltage and current 250-650 kV and 10-55 kA, respectively.
Marx...
High-power electromagnetic fields and currents in the excitation and propagation in the ground is of a significant interest for numerous applied problems. A pulsed electromagnetic field source has been developed for the related purposes. The source is designed as a dipole (vibrator) antenna, excited by the high-current pulsed discharges.
The usage of a dipole with a high input capacitance and...
Following impulse excitation of the primary winding of a Tesla transformer, the secondary response contains a fundamental component plus higher-order mode. The paper will describe a winding technique that enables the higher-order modes to be suppressed, and so provide a transformer output with an improved spectral purity, that is better suited for use in many high-power applications than...
As a relatively new kind of the pulsed power supplies for electromagnetic launchers, the IPPS (inductive pulsed power supply) attracts researchers’ attentions with the major advantage of high energy storage density. However, it possesses one major disadvantage: too much energy remained in the energy storage inductors and then wasted in the muzzle resistor after the projectile (or armature)...
A key parameter for the compressor operation is the switch performance, transferring from a storage (high Q) phase to release (low Q) phase. By initiation of plasma due to a gas discharge phenomenon it is possible to drastically change the boundary conditions and enable a fast phase transfer.
In this work, we investigate the use of a high peak power laser pulse to generate seed electrons and...
The majority of publications dealing with Tesla transformers are confined to studies of their performance based on a familiar lumped equivalent circuit. This paper will differ from these in being concerned with the very important and practical issue of the coupling between the two transformer winding. It will consider the importance of the coupling factor for different practical applications...
The paper will describe experimental studies of magneto-forming technology, undertaken at Loughborough University and using the existing 2 MA/100 kJ Quattro capacitor bank as power supply. Five different practical arrangements will be detailed and results presented that illustrate:
- Welding aluminium cylinders with galvanized steel cylinders in theta-pinch geometry
- Welding stainless steel...
A pulsed power induction coilgun system is a multi-physics system that is too complicated and difficult to simulate and design. Several studies presented design and simulation schemes of a coilgun system by a finite-element method (FEM) which is not cost-effective and need time-consuming process. The impact on the energy efficiency by capacitance, voltage level, and initial position of...
This paper presents the n stage dynamic model generalization for bipolar Marx Generators, during the capacitors charging mode, to estimate the generator pulse repetition rate.
Bipolar Marx Generators are based in modular solid-state switching stages. Their operating principle can be reduced to two operating modes; Mode-I - Capacitors charging and Mode-II – Output pulse forming. In mode I, n...
The Townsend breakdown theory is generally applicable in the case in which a DC voltage is applied to a gap filled with gases. The result of Townsend breakdown theory is generally not applicable directly in the case in which a high-power microwave propagates in the atmosphere. In this paper, we develop a theoretical model to describe the breakdown of high-power microwave propagation in the...
The most prominent advantage of Brooks-type coil is that it can obtain the highest energy storage density and the resistance of per unit inductance coil is smaller. However, the biggest problem of the Brooks-type coil is that there is a very large fringe field around it. For preventing electromagnetic radiation interference, it is necessary to consider the safety distance between the coil and...
Application of microwave plasma offers a potential method to produce faster combustion in internal combustion engine1. In this paper, microwave multi-point ignition and spatial ignition had been confirmed via high-speed Schlieren imaging technique. The experiment was implemented with the microwave resonant ignition system and the Schlieren optical system. 2ms-3000W-2.45GHz plused microwave...
Perfluorinated liquids are attractive for use in high-voltage devices because of their chemical stability under electrical discharges. For applications like liquid spark gaps, the breakdown velocity is an important parameter. In this work, we present the results of measurements of the anode-initiated electrical breakdown velocity at 140 kV in perfluorinated liquids of several chemical classes....
A new architecture of high voltage pulse generator has been proposed. It is based on combining two types of switches’ technologies, namely IGBT used as opening switch and spark gap used as closing one, and two types of energy storage, Inductive and capacitive, in order to get a compromise with a better performances dedicated especially for embedded applications.
This new architecture has...
Inductive Output tubes (IOT) or klystrodes are used to produce RF power in several industrial, research and medical applications. TV broadcasting and industrial heating represent the biggest percentage of these applications. In these cases the RF power is required continuously, and therefore classical IOT power system topologies are based on a high voltage DC power supply, together with...
The gouging phenomenon on the surface of the sliding contact of an electromagnetic launcher is one of the major problems to realize it in practical uses. The resistive overlay is known as one of the solutions to overcome the gouging on the rail surface even though the energy transfer efficiency to the projectile is reduced due to the increase of the rail resistance.
We conducted the...
Vircator can generate GW class microwave power and is the preferred device in certain military application due to its simple structure and lighter weight because no magnet is used. Previous investigation [1] leads to the conclusion that applying a magnetic field on vircator is going to decrease its output power, to the extent eventually a total cutoff. However, previous study was conducted...
Compulsators (compensated pulsed altarnators) are ac generators designed maximize the short circuit current that could be delivered to the load. The role of the compensation (active/passive/selectively passive) is to minimize the inductance of the alternator during the discharge process. Over the last three decades, many topologies of the compulsator have been evolved in order to achieve a...
Periodic structures that reduce the velocity of electromagnetic wave propagation are widely used in electron beam driven high power microwave sources. When the frequency increases into the mm-wave region such structures become difficult to manufacture because of the small physical dimensions. “Additive Manufacturing” or “3D printing” offers the possibility of constructing certain types of...
Investigation of phase control in a klystron-like relativistic backward wave oscillator is presented in this paper. The guiding magnetic field, the distance between the input cavity and the pre-modulation cavity, the rise time of diode voltage, and the input signal frequency are optimized to decrease the phase jitter of output microwave. Particle-in-cell simulations show that when the diode...
The goal of this study is to design an Ultra-Wide Band (UWB) antenna for a High Power Microwaves (HPM) application. Classical antennas must be compatible with the bandwidth, the impedance of the system, and with the radiation characteristics (gain, directivity, and polarization). However, additional constraints such as high-voltage transient input signals have to be considered in the case of...
Plasma activated water (PAW) has gained increasing attentions for a wide range of applications in the biomedical fields. Especially PAW are known to inactivate microbial cells effectively. Gas-jet assisted nanosecond pulsed discharge in the water was used to produce PAW. Nanosecond high voltage pulses from a five-stage Marx-generator were applied to two electrodes installed in the distilled...
The paper presents the study on the plasma chemical synthesis of nanocomposite carbon-bearing powders based on SiO2 and TiO2 and the analysis of their main characteristics. The nanopowders were synthesized in the plasma chemical reactor using a pulsed electron beam for the low-temperature plasma generation. The experiments on the synthesis of powders were carried out using a TEA-500 pulsed...
References [1-3] studied contactless skin-effect opening switches (SEOS) in combination with semi-conductor opening switches (SOS) and plasma opening switches (POS). This paper proposes to review in greater detail one of these combinations: a SEOS and an SOS. This combination has several attractive properties: durable functioning of each component and a good ratio of charging time to energy...
Abstract- The evaluation of pulsed power systems and their constituent components requires unconventional loads with exceptional voltage, current, impulse energy, and continuous power dissipation capability. This paper presents the design and construction of a reconfigurable resistive load with active temperature monitoring for the evaluation of ultra-high voltage pulsed power modulators and...
Sheet beam klystrons have many advantages over traditional round beam klystrons that are desirable for a variety of applications. They can operate at a high efficiency and relatively low voltage by keeping the perveance per unit area of the electron beam low. This is achieved by spreading the beam out in one dimension which decreases the current density and power density. They can produce...
Activation of water using pulsed electric discharges serves several important agricultural and biomedical applications. Plasma activated water (PAW) contains reactive oxygen and nitrogen molecular species (RNOS) like hydrogen peroxide H2O2, nitric acid HNO3, nitrous acid HNO2 and peroxynitrite ONOO-, exhibiting strong antiseptic power. TU/e spin-off company VitalFluid develops generators for...
The existing fusion technology is mainly based on the microsecond pulse electric field. However, there is a great defect in the traditional fusion technology: the microsecond pulse electric field is sensitive to the cell size, and it is difficult to realize the effective fusion of cells with different sizes. There was a significant positive correlation between the transmembrane potential and...
The object of the study is a pulse transformer with a toroidal magnetic core wound by a transformer steel strap operating under short voltage pulses, at which the magnetic field has no time to steady in the core material. The pulse magnetic field diffusion in the steel strap of the core was analyzed using a 1-D model of dynamic losses, covering the effects of hysteretic and excess losses [1]....
The Hermes III accelerator at Sandia National Laboratories is a 20 cavity multi-stage linear induction voltage accelerator typically producing a 20-MV, 20-ns, 600-kA output pulse. Energy is initially stored in Marx banks that are each discharged into two intermediate store capacitors. Each of these capacitors are then switched with an SF6-insulated high voltage rim-fire gas switch into four...
Application of high-intensity electric fields and/or currents is known to enhance materials’ deformability. For instance, a high-density electric fields/currents applied continuously (CC: continuous current) or in short pulses (PC: pulsed current) on metals and ceramics may significantly affect their deformation response to external loads. This phenomenon is commonly referred to as...
In present theory of vacuum surface flashover, secondary electron emission avalanche (SEEA) plays the dominant role in surface flashover development. But more and more researchers have the opinion that surface trapping can participate in the SEEA development and significantly affect the surface flashover characteristics of insulation materials in vacuum. The trap parameters of several typical...
Two pulsed power arrangements have been designed and tested, both based on a circuit containing an air-core pulsed transformer and a miniature explosively-driven flux-compression generator. The power supply in both cases is provided either by a conventional HV charger or by a PZT autonomous power supply. For both pulsed power arrangements, output voltage oscillations with a peak close to 100...
Taiwan Photon Source (TPS) is an accelerator particle ring. This facility provides with a high luminance and stabilize source in which electron beam is produced form linac via a booster ring to storage ring for user studies. After electron beam is stored in the ring, its power would lose due to the energy dissipation. A RF Cavity (Nb,5 Cells) in Booster Ring is used to compensate the lose...
A triggered vacuum switch (TVS) was designed with a flat electrode at the beginning and developed to a multi-gap electrode which reduces heavy electrode erosion. Recently the demands of the TVS is increased, as the high power system is extended in the various fields. It invokes the improvement of the performance for a TVS, therefore, a fast camera experiment is suggested to research the...
The lifetime of high voltage ceramic capacitors (HVCC) are always shorted because of suffering from circularly electrical, thermal and mechanical stresses, electric field concentrations and high current density. The reasons shall be analyzed and measures should be taken to prolong the lifetime of HVCC.
In this paper, a repetitive frequency testing platform was setup to study the influence of...
A triggered vacuum switch (TVS) is widely used as a closing switch in the field of high pulsed power systems. A designed final sealed-off TVS is aimed to operate at maximum voltage of 20 kV with maximum current of 150 kA, a lifetime more than 1000 shots. Before we reach the final goals, a sealed-off prototype with Cu electrodes is fabricated to recognize a full producing process. This...
This paper describes the hardware changes made to the triggering systems of the HERMES III accelerator at the Simulation Technology Laboratory (STL) at Sandia National Laboratories, New Mexico. The HERMES III accelerator is a gamma ray simulator producing 100kRad dose per shot with a full width half max pulse duration of ~25 nanoseconds and averages six shots per day. For each accelerator...
As a new kind of kinetic-energy weapon system, electromagnetic railgun possesses one major advantage of high muzzle velocity which can be controlled artificially and accurately. Since the muzzle velocity error has a great influence on the hit rate, accurate velocity control is of importance. However, existing literatures focus more on the maximization (or promotion) of the muzzle velocity,...
The generation of high-power electromagnetic waves is one of the major applications in the field of high-intensity pulsed power. The conventional structure of a pulsed power generator contains a primary energy source and a load, separated by a power-amplification system. The latter performs a time-compression of the slow input energy pulse and delivers a high-intensity power output to the...
NRLs’ Nike laser produces up to 3 kJ at 248 nm on target, and was the culmination of simultaneous advancements in pulsed power, the production and control of large area high-energy electron beams, and excimer laser physics. Nike has demonstrated excellent beam smoothing via ISI, the ability to mitigate CBET via focal zooming, the efficient acceleration of targets to high velocity, and the...
Various modern applications like fusion reactors for plasma generation, beam deflecting equipment in accelerators, equipment for magnetic resonance imaging (MRI) and test equipment for future HVDC breakers, require highly dynamic, high power pulsed current sources. Such current sources must provide a high current gradient combined with an ultra-low ripple and a stable operation under...
The standard solid propellant fueled pulsed MHD generators with an electric power of 10–600 MW developed in the 1970-80s provided reliable autonomous power supply of various consumers. The time required for such MHD generators with self-excitation to reach the rated operating conditions is about one second. Recently new scientific, engineering, and technological results have been obtained that...
High voltage modulators (HVM) have been used widely for broadcast, medical, industrial and research applications. The most common modulation techniques for HVM are Pulsed Step Modulation, Coarse Step Modulation, PWM and their hybrid modifications.
All these methods require a presence of PI-controller with additional Feedforward loop in control system to estimate a modulation index or duty...
The Z machine is a 36-module, multi-megavolt, low impedance driver for high-energy-density physics experiments. In 2007, a major rebuild doubled the stored energy and increased the peak current that could be delivered. The upgraded system can drive 27 MA through dynamic plasma loads with 110 nanosecond time to peak current. The Z pulsed power system is expected to be prepared for a...
Initially this paper will outline a theoretical study, using commercially available software CST, into the use of off-the-shelf V-dot sensors made from N and SMA type adaptors and connectors. A complex issue arising from the distortion of the signal measured within a pulse forming line when the sensor is mounted close to a spark gap will be clarified.
Other issues relating to calibration of...
The MagLIF (Magnetized Liner Inertial Fusion) concept[S.A. Slutz et al. Phys. Plasmas 17, 056303,2010] has produced 3.e12 DD neutrons on the Z-machine [M.R. Gomez et al. Phys. Rev. Lett. 113, 155003, 2014]. 2D simulations using the measured fuel preheat,800 J, and drive current, 17 MA, predict 6.e12 DD neutrons. We show that even better agreement is obtained when the effect of electrode...
Two parallel Marx generators drive the primary of a pulse transformer with the transformer secondary driving a Klystron as part of a novel system developed by Stangenes Industries. A parallel Marx topology is used to reduce the current contribution of each Marx to an acceptable level so as to not require an export-controlled switch. This allows the system freedom of commercial convenience....
Abstract
Capacitors for pulse power applications have been custom-designed to maximize specific energy while operating with specific circuit requirements such as charge voltage, peak current, voltage reversal, series inductance and resistance, charge time, hold time at peak voltage, and pulse repetition rate. In addition, these capacitor designs had to meet application-specific constraints...
The National Ignition Facility, the most energetic laser in the world, focuses 192 laser beams on a pea size target inside a vacuum chamber to create temperatures and pressures that exist naturally only in the cores of stars and giant planets. Besides relying on three major pulsed power systems, the NIF facility is the shell for several other pulsed power developments, with applications...
Nowadays, it is important to improve the power efficiency with the growing variety of environmental, biological, medical, and especially for homogeneous dielectric barrier discharges (DBD) industry application using a repetitive high-voltage solid-state Marx generator. However, most solid-state pulse generators are action at hard switching on or off, such as a huge current for the DBD load,...
Spark gap switch resistance and inductance are important parameters in pulsed power systems. However, the variation of switch resistance can be a difficult parameter to measure in very high voltage environments where the arc resistance is a small fraction of the total impedance. To improve our ability to model spark gap switches, we built a coaxial geometry system and tested switches with a...
Sandia’s Z Machine can deliver up to 27 MA in ~100 ns to drive high-energy density physics experiments. These parameters are achieved in part via use of four parallel Magnetically Insulated Transmission Lines (MITLs) that reduce overall system inductance. A Double Post-Hole Convolute (DPHC) acts as a current adder to combine the four parallel MITLs into a single transmission line. The DPHC...
In 2014 the Saturn accelerator located at Sandia National Laboratories was brought back online after nearly a year of inactivity. The Saturn accelerator is made up of 36 individual pulsed power lines which consist of a 2.7-MV Marx generator, intermediate storage capacitor, 3-MV rim fire gas switch, pulse forming and transmission line. Each component has an individual diagnostic that measures...
A low-current-fusion (LCF) ignition path below 6 MA is hinted by high-gain high-field (HGHF) plasma within tokamak vacuum vessel due to recent successful experiments of magneto-inertial fusion (MIF) [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] and earlier experiments of compressed plasma in tokamaks. MIF shares the same principle of magnetic compression and physical process as...
In an Inductive Pulse Power Supply (IPPS), when the inductors are charged and discharged, they face different capacitive loads, i.e. the frequencies of charging and discharging are different. According to our experiences, inductors’ inductances and resistances may change with frequencies. If constant inductance and resistance for one inductor are used in simulation, errors may occur. So it is...
we are planning to build an linear-transformer-driver (LTD) based accelerator for driving wire-array Z-pinch loads. The accelerator comprises six modules in parallel, each of which has eight series 0.8-MA LTD cavities in a voltage-adder configuration. Vacuum transmission lines are used from the interior of the adder to the central vacuum chamber where the load is placed. Thus the traditional...
In the framework of a collaboration, CEA and CERN are working on an air insulated solid state pulse modulator to drive LEETCHI electron gun, source of future high current, long pulse RF accelerator. The requirements are pulses in the range of 140kV (1% flat top), 10A, 150μs width, at a repetition rate up to 50Hz and a reproducibility pulse-to-pulse better than 10-3. The proposed modulator is...
In the framework of the CLIC project at CERN, the team in charge of the study of the klystron modulators faces new challenges to achieve high precision and repeatable pulses. This challenge consists in generating precise and repeatable pulses of 140µs at 50Hz. The pulsed power is 30MW at a voltage of 180kV.
This paper presents the study and the evaluation of a new hybrid bouncer circuit. It...
The Cygnus Dual Beam Radiographic Facility consists of two identical radiographic sources each with a dose rating of 4-rad at 1 m, and a 1-mm diameter spot size. The development of the rod pinch diode was responsible for the ability to meet these criteria¹. The rod pinch diode in a Cygnus machine uses a 0.75-mm diameter, tapered tip, tungsten anode rod extended through a 9-mm diameter,...
First Light Fusion Ltd is a privately funded company in the early stages of researching energy generation using inertial confinement fusion. Efforts are currently centred around developing both simulation and experimental capabilities. First Light Fusion (FLF) currently operates a two stage light gas gun which is capable of projectile velocities approaching 8 km/s, and two low inductance...
A dual-module Aerogel Cherenkov Detector for Cygnus (ACD/C) was used to measure the X-ray energy spectrum from Cygnus – an intense flash X-ray source operated at the Nevada National Security Site. The ACD/C employs an array of SiO2 aerogels & solids (i.e., quartz) at different densities (50 – 2500 mg/cc) and hence varying Cherenkov energy thresholds (2.8 MeV X-ray energy for aerogel with 50...
A modular pulsed-power driver has been developed to create an applied magnetic field for high-intensity laser experiments. The system is presently being using on Sandia’s Z Beamlet Laser facility and was previously used at the Texas Petawatt laser facility at the University of Texas at Austin.. Its design includes use of low inductance circuit elements, a single-turn coil, up to six 3.1 µF...
The presentation reviews the results of studies on the SOS effect – nanosecond interruption of superdense currents in semiconductor diodes – and its application in high-current electronics for powerful nanosecond pulse generation. The base physical processes that determine the mechanism of operation of opening switches, which are based on the SOS effect, are considered. Design and...
We have developed a conceptual design of a next-generation pulsed-power accelerator that is optimized for high-energy-density-physics experiments. The design is based on an architecture that is founded on two concepts: single-stage electrical-pulse compression and impedance matching [Phys. Rev. Accel. Beams 10, 030401 (2007); 18, 110401 (2015)]. The prime power source of the machine...
The Inductively Driven Liner (IDL) concept represents a transformational solution to the generation of fusion energy. A fusion gain demonstration device is described that would serve as a smaller-scale, prototype of the commercial fusion reactor, and would demonstrate all essential aspects of the reactor from the ability to form, heat, and confine plasmas at performance levels and establish...
The work will present the most recent phase in the development of a GW-class pulsed power generator intended for medical and biological applications. Based on a Tesla transformer charged Blumlein pulse forming line, the generator output is connected to a bipolar former capable of producing approximately sinusoidal 1 GHz, 600 kV peak-to-peak voltage impulses. The bipolar output feeds an...
It is known that the properties of pulsed current filaments can affect the efficiency of ozone generation[1]. In this paper, a statistical analysis was made to investigate the properties of the current filaments observed in dielectric barrier discharges with meshed electrodes. Two stainless-steel sheets with 0.96 mm apertures were used as the meshed electrodes. A 5 kHz smart power supply was...
A fast rise time air insulated Linear Transformer Driver (LTD) has been constructed by a collaboration between the University of New Mexico and the Naval Research Laboratory to drive high energy density physics experiments. The LTD is comprised of 12 bricks, each consisting of two 100 kV capacitors tied to a multi-electrode low inductance switch. Details of the construction, including...
MagLIF is a promising inertial fusion based platforme studied on the Z machine, at Sandia National Laboratories. This fusion scheme combines z-pinch liner implosion, laser heating and magnetic field confinement. A wealth of physical processes can be studied using this platform, from electron heat conduction to magnetic field compression, from magnetic Rayleigh-Taylor instabilities to particle...
Powerful dynamic shock waves induced by pulsed discharge in water has been widely adopted in many industry applications, such as material processing, rock fragmentation, electrohydraulic cleaning, high intensity ultrasound source, et al. It is necessary to research on how to induce shock waves steadily and efficiently. An experiment stand of pulsed discharge is designed and constructed, based...
The most powerful pulse power generator in China - the 10MA PTS facility was used to compress Al samples to pressures over 100GPa. Tens of isentropic compression experiments (ICE) have been conducted at the time of this conference, among which two distinct loading profiles were designed to get different compression processes. A smoothly increasing current was applied to get a shockless and...
Many industrial-scale electroporation devices are driven by Marx generators. Thereby, the pulse circuit comprising the Marx generator and the electroporation reactor needs to be tailored specifically to the requirements of the application. Biological material for electroporation-assisted extraction processes is treated at pulse lengths on the order of several microseconds. For large-scale...
Recent trends in the further development of pulsed power technology are towards higher power, longer duration and more compact structures. Compact pulsed power generators based on a Tesla transformer, configured using coaxial pulse forming lines, are widely used in the application of pulsed power systems. Limited by the low permittivity of the traditional energy storage medium (transformer...
Large multi-megampere pulsed power accelerators face current loss issues in combining multiple magnetically insulated transmission lines (MITLs) into a single radial disk feed for loads such as Z-pinch radiation sources, shock physics experiments and fusion studies. The method used in many of these machines is the post-hole convolute (PHC) where the MITLs are joined very near the load region....
GEPI, developed in 2002 [1], has been the first compact pulsed power driver using strip line loads for isentropic compression experiments (ICE). Still in full operation, it delivers 3.5 MA with a 500 ns rise time and its main use is for ICE around or below GPa level, with load width less or equal to 70 mm. Because of its high availability, its reliability and ease of operation, this kind of...
Traditional shock wave physics experiments require the high precision (uniform) impact by a solid driver at well known, and controllable, velocity upon a target. Combining initial shock heating with controlled compression can provide access to the challenging conditions called warm-dense matter. High velocity, electromagnetically driven cylindrical liners can be a convenient and controllable...
Plasma in contact with water has been widely investigated for the production of reactive species such as H2O2 and OH radicals [1]. In this research, both positive and negative pulsed corona discharges, with duration of the order of microseconds, were used to investigate hydrogen peroxide formation in a pin-to-water electrode system.
Under positive pulsed corona discharge, hydrogen peroxide...
Linear transformer driver (LTD) is a new technical approach that can deliver fast high current and high voltage pulses with very compact devices. Traditional LTDs generate sinusoidal shape pulse by LC discharge, while many situations such as FXR and HPM need square pulse. This paper presents a new technical scheme for square pulse LTD in which simplified PFN take the place of LC “bricks” in...
A very important topic in the field of electromagnetic accelerators of the railgun-type is the realization of an appropriate power supply. So far, three different ways of storing energy for railguns have been explored: electric fields, magnetic fields and kinetic energy corresponding to capacitors, storage coils and fly wheels respectively. The project to be presented here and funded by the...
The Richtmyer-Meshkov Instability (RMI) has been extensively studied in fluids in planar geometry. Not so well studied are the effects of converging geometry. The portable LANL PHELIX capacitor bank (Vpeak = 100 kV, Ustored = 340 kJ) coupled with the LANL LANSCE multi-frame proton radiography (pRad) facility radiography makes this possible. The PHELIX pulse (tpulse ~ 6 us, 1 < Ipeak < 5...
The Michigan Accelerator for Inductive Z-pinch Experiments (MAIZE) is a 3-m-diameter, single-cavity Linear Transformer Driver (LTD). MAIZE supplies a fast electrical pulse (0–1 MA in 100 ns) to various experimental configurations, including wire-array z-pinches and cylindrical foil loads. MAIZE is the first LTD of its kind in the United States, and it has been operational at the University...
Abstract: Bipolar pulses have advantages in reducing muscle contraction and increasing electric field uniformity in the treatment of tumors. In order to study the bio-medical effects in the treatment of tumors exposed to bipolar and high pulse repetition frequency (PRF) nanosecond pulse electric fields, a compact pulse generator which meets the requirements above is needed. A novel...
The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. To avoid beam emittance increase, the DR kicker systems must provide extremely stable field pulses during injection and extraction...
Plasmas exhibit properties that make them useful in a wide range of applications, such as lighting, semiconductor processing, nanometer lithography, surface treatments, fusion energy, plasma medicine, future fuels, plasma agriculture and environmental applications. Within this large area, pulsed-power driven, transient plasmas perform much better in energy efficiency and processing...
The high pressure created by magnetic field which was induced by the current flowing through the flyer allows one to reach the megabar pressures and to accelerate the flyers to high velocities. For intense impact of this flyer onto the studied substance it is necessary that a significant portion of the flyer had the density close to the density of the solid. But a part of the stored energy...
We describe new opportunities of pulse power multiplication using the load current multiplier concept (LCM) [1]. The LCMs were already demonstrated to increase current both in inductive energy storage and pulse forming line systems [2], including experiments at the enhanced current of 1.7 MA on Zebra [3]. Recent successful validation of this approach on Z for the current up to 10 MA [4] allows...
The ElectroMagnetic Flux Compression (EMFC) has important applications in solid-state physics (ultrahigh magnetic field physics, high pressure science), and is also likely to find applications in fusion and high-energy density researches.
In the Institute of Fluid Physics (IFP), Chinese Academy of Engineering Physics (CAEP), a medium-sized EMFC device has being developed to carry out some...
The pulsed-power accelerator uses its parallel branches triggered to shape the load-current pulse as required for a material physics experiment. We obtained the energy efficiencies is only depended of the pulsed power accelerator impedance and the load impedance with any order of the branches triggered. It is the highest that the pulsed power accelerator impedance (impedance of the parrallel...
For generating such pulses, a long pulse modulator based on a modular series parallel resonant converter (SPRC) topology has been developed [1]. This converter is operated at a high switching frequency (100kHz) to minimize the dimensions of the reactive components and the transformer. In order to generate the required output voltage of 115kV, 8 SPRC modules each with a transformer secondary...
The design of multi-pulses, multi giga-watt, high voltage generators is of particular interest for electron beam induction accelerators. The major requirements for this type of pulsed power generators are a few percent flat top, a jitter in the range of 1 ns, high pulse reproducibility shot to shot and a drastic reliability. As an opportunity for future flash X-rays
machines, CEA is developing...
High-stability flat-top pulsed magnetic field, which combines the advantages of pulsed high magnetic field and steady high magnetic field, is an important tool of scientific experiments in the fields of physics, biology, and chemistry. The pulsed generator-rectifier power supply, with controllable output voltage, is commonly used to power multi-coil magnet to generate synthetic flat-top...
High magnetic field is an important research tool for magnetization measurement, which can help scientists to observe the physical phenomena and collect data such as Feimi surface structure and the superconductivity critical parameters. In order to meet the testing requirements of various materials, a new flexible capacitive pulsed power supply to the high magnetic fields for the magnetization...
High pulsed magnetic field is an important research tool for frontier science. In order to achieve 100 Tesla pulsed magnetic field, a high energy hybrid pulsed power system consisting of pulsed generator, battery banks and capacitor banks is designed to energize the magnet at the Wuhan National High Magnetic Field Center (WHMFC). The magnet has a structure of three coaxially nested coils. The...
Repetitive pulsed magnetic stimulator has been verified as an important device for psychological and neurological disorders. However, repetitive pulsed current in time-varying magnetic field produces large Joule heat in coil which undermines curative efficacy and prevents repetitive high frequency stimulation.
After analyzing the advantages of existing coils and the unique nonplanar structure...
Although W-Cu alloy is widely adopted in breakers and spark switches as a kind of anti-ablation material, a series of problems including restrike, flashover, etc. still exist. For spark switches in pulsed power equipment, electrode erosion will cause a lot of problems. Not only the electrode surface, but the insulator surface can also be altered from shot to shot. Therefore, the selection of...
Abstract-
We study in this article by a numerical model the
plasma characteristics of dielectric barrier discharge in
pure xenon. The 1D Siglo T-R model developed in this
paper is based on the resolution of two moments of
Boltzmann equation with approximation of local electric
field. The discharge model is driven by an external
sinusoidal voltage waveform and was achieved and
studied in the...
High energy density physics experiments often require the use of short pulses of hard X-ray probing radiation to make measurements of the conditions produced – for instance using X-ray diffraction to examine phase changes as a material is subject to multi-Mbar pressures. In pulsed power experiments such probing radiation has often been produced by an X-pinch, where two or more crossed fine...
The Spallation Neutron Source (SNS) beam chopping system uses a segmented electrostatic lens in the Low Energy Beam Transport (LEBT) to deflect the beam out of the RFQ input aperture to create gaps in the 1ms beam macro-pulse for extraction from the Ring, or fully displace the beam. The lens is split azimuthally into four quadrants which are pulsed independently by four bipolar high voltage...
Exploding films have potential applications as fast opening switches, current interrupters, and in the ignition of explosive materials. The exploding film phenomenon is a process in which a high voltage capacitive discharge is passed through a thin layer of metal particles on the surface of a dielectric film. Heat generated from the increase in current forces the aluminum particles from a...
This work presents a novel, compact, and portable x-pinch radiation source developed and tested at Idaho State University. The salient features of our x-pinch radiation source are its simplicity, compactness, and portability: there is no oil, no water, and no SF6. It can be easily relocated to any place where a compact x-pinch radiation source is wanted. Despite its simplicity, it generates a...
High power Gamma facility is being developed at Russian Federal Nuclear Center (VNIIEF) for generation of X-rays. Potential of this facility at full 16 module variant (maximal current to the load up to 10 MA) and initial 4 module variant (maximal current to the load 3 MA) can be used to study the warm dense matter (WDM) and material properties in the megabar pressure range. Some results are...
Sulphur hexafluoride (SF6) has traditionally been used as a switching medium within corona-stabilised switches (CSS). Due to its high global warming potential (GWP), however, other gases are under test in order to find a suitable alternative that can be used within CSS, without compromising on switching performance. Design changes may have to be made in order for the switch to remain at the...
In recent years, treatment approach of malignant neoplasm (cancer), which has high death ratio , has been actively studied. There are several current cancer therapy as radiation therapy, surgical therapy, and chemotherapy (anticancer drugs), but these therapy have some disadvantages. The purpose of this study was to establish a new cancer therapy, using nanosecond pulsed electric fields...
Two types of the high-voltage cells are developed for a 20 MeV, 2 kA linear induction accelerator and a 2 MeV injector. Each accelerator’s cell incorporates 16 inductors, it is supplied in an inductive voltage adder manner with a pulse voltage up to 336 kV and different flattop duration of 60-380 ns. At the first stage the cells were tested in a 60 ns pulse mode, the test results with an...
The Spallation Neutron Source (SNS) utilizes an electron scanner in the accumulator ring for non-destructive transverse profiling of the proton beam. The electron scanner consists of a high voltage pulse generator driving an electron gun, a medium voltage ramp generator, and a CCD camera. A new high voltage pulse generator that provides 100 kV pulses with rise times of less than 200 ns,...
In the recent decades, together with power electronics technological advancements, an emerging technology, solid state transformer (SST), has attracted great attention and been extensively investigated for smart grid, while mainly focusing on the research of available and efficient circuit topologies. As the core component of SST, the high frequency power transformer, which replaces the...
Disk magneto-cumulative generators with opening switches are used to generate current pulses of tens of megaamperes with a front of less than 1 µs in the liner loads. It is necessary to locate the foil at the large diameter to decrease the linear current density in the destroyed conductor; and hereby, to decrease the specific power of the thermal energy dissipating in the opening switch. This...
Ever-increasing energy demands require new energy sources. Modern oil extraction industry is targeted at extracting oil products at larger depths [1]. Some European countries, for example, Switzerland, Germany, develop technologies for geothermal energy harvesting from the natural heat of the Earth [2]. Accomplishing these goals needs new scientific approach to deep and ultra-deep drilling....
Nowadays, water pollution is one of the environmental problems. We have studied a sewage treatment using nanosecond pulsed power discharges. A surfactant was chosen as a treatment object because much surfactant occupies to domestic and industrial wastewater.
In order to reduce the costs for treatment, treatment using air gas as a discharge gas was studied. The treatments using streamer...
Dielectric Elastomer Actuators (DEAs) are a class of electroactive polymers, materials which exhibit a mechanical strain as a response to an electrical stimulus, capable of achieving high actuation strains over 100 %. A key hindrance in the application of DEAs is their need for high voltage in order to actuate, leaving their operating range close to their breakdown range. Therefore, this work...
Nowadays, environmental problems such as global warming, air pollution and acid rain are getting worse. Nitrogen oxides (NOx) are one of causative substances of them. NOx adversely affects not only the environment but also human body. Development of the NOx treatment measure is, therefore, an important issue. In the conventional NOx treatment method, the treatment equipment is large and...
Modern high-voltage auto-expansion circuit breakers utilize the gaseous medium flowing through a supersonic nozzle to produce adequate conditions for arc quenching at current zero. The behaviors of arcs burning in such nozzles are closely related to the properties of the medium. SF6 is currently used as working medium because of its excellent dielectric properties. However SF6 is a strong...
Pulsed electric fields have recently demonstrated their broad application potential in novel non-thermal minimally invasive techniques to treat cancer because of their unique biomedical and therapeutic effects. However, their practical clinical applications are limited by poor understanding of the interaction mechanism between pulsed electric fields and tissue, particularly in the process of...
Recently the research pace in the field of laboratory astrophysics is rather high. Powerful lasers became an important class of experimental setups for laboratory astrophysics. Currently, it became possible to increase the laser pulse energy up to hundreds of joules while reducing the duration to hundreds of femtoseconds, which corresponds to reaching the petawatt power level. By this means...
Nowadays, in pulsed power applications, during the design of a modulator, it is necessary to take into account all problems linked to insulators and their capability to withstand a dielectric strength. Indeed, many of these modulators integrate transformers, allowing a significant increase of voltage. So, the first objective is to provide an adequate insulation to maintain compact size.
This...
The pressure waveforms of shock waves generated by exploding copper and tungsten wires have been recorded and analyzed. A test platform including a microsecond time scale pulsed current source, loads, a chamber, and a diagnostic system has been established. Current and voltage waveforms were recorded by a Pearson coil and a North Star probe, respectively. Shock waves were obtained by a PVDF...
Generally, the performances of high power electron beam diode, such as current levels, impedance collapse, and plasma expansion, have been attributed to the combination of the cathode and anode instead of just the cathode. The issues of anode have been paid more and more attention in research and practical applications. In this paper, five kinds of anode materials, stainless steel, titanium...
It is now becoming clear that future applications of the readily available form of antimatter,namely positrons,especially in the form of power high brightness positron beams,will lead to the excellent progress in a few avenue of inquires of HEDP and,consequently,it will be next stop for HEDP experimental basis.Especcially,this is concerning with clue and stubborn problems as high velocity...
This paper presents investigation results of the helical magneto-cumulative generator of 100 mm diameter intended for plasma focus powering by the current of more than 2 MA. A cylindrical explosive current opening switch with copper foil located on the 100 mm diameter is used to form a current pulse with a steep front in the plasma load. The magneto-cumulative generator has an effective...
Irreversible electroporation (IRE) with non-thermal has quickly translated into clinical applications for solid tumors ablation. However, muscle contractions and tumors recurrence also come with IRE. Bursts of high frequency bipolar pulses have been reported may solve these problems appropriately, but muscle contractions need further reduction and the ablation effects and uniform electric...
One of the main characteristics of the equation of states (EOS) is zero isotherm (i.e. a curve of the “cold compression”). Particularly, it defines the substance compression in the condensed phase. The substance behavior study and, first of all, the study of their equation of states at ultrahigh pressures and low temperatures is one of the fundamental tasks of high energy density physics. ...
Recent experimental results on strong shock wave (SSW) convergence are presented. Converging SSW was generated using underwater electrical explosion of a spherical wire array with radius of either 10 mm or 15 mm. Arrays were composed of 40 either Al or Cu wires. Wire diameter was adjusted to obtain the aperiodic discharge current with amplitude ≤240 kA and rise time of ≤800 ns. As a result of...
Over the past two decades, polymeric nanocomposite materials have been the centre of great attention in the research community. Mixing low concentrations of metal or metal-oxide nanoparticles into polymeric insulators has been shown to improve key characteristics of the material, such as thermal behaviour, mechanical strength and resistance to long-term degradation. Unlike traditional...
Regarding semiconductor-device production, ion-implant energy is decreasing since the junction depth becomes shallower along with the shrinkage of device size. The lowest energy level for practical use has been around several 100eV and will become lower than 100eV in a near future [1]. For realizing such low-energy beams, ions are decelerated before implantation. We reported in the past that...
In the application of reservoir stimulation, pulsed discharges may happen in a liquid environment with a quite high hydrostatic pressure (from several mega Pascal to a few tens of mega Pascal). It might be meaningful to investigate the behaviors of the wire explosion process under some hydrostatic pressures. Current and voltage waveforms were recorded by a Pearson coil and a North Star probe,...
The Saturn Accelerator at Sandia National Laboratories was originally designed as a short pulse, negative polarity machine with a power pulse width of approximately 28 ns feeding a three ring diode bremsstrahlung x-ray source supporting the machine’s primary function as a high dose-rate x-ray simulator. For upcoming x-ray source designs such as the reflex triode, the machine must be operated...
The new electron accelerator GESA-SOFIE for long pulse operation was specially designed for in-situ diagnostics and investigation of the beam characteristics and operation performance under different conditions. One of the new features is the possibility to tune the shape and position of the electrodes. The use of a planar cathode necessary to optimize the diagnostics, for instance, makes an...
Abstract- As Silicon is reaching the theoretical limit, wide bandgap devices such as Gallium Nitride (GaN) transistors are being investigated as replacements for Silicon in high voltage and high temperature applications. To have a better understanding of GaN power devices operating under long term high peak current conditions, GaN devices were switched under the following conditions: high...
Presentation demonstrates the results of measurements of the plasma boundary velocity during the compression of a metallic gas-puff Z pinch in an axial magnetic field. The experiment was conducted on the IMRI-5 facility (current pulse of 450-kA amplitude with a 450-ns rise time); the initial magnetic field Bz0 was varied in the range 0.15–0.6 T. The trajectories of radius vs time were...
Recycling of valuable materials such as metals and plastics is regarded as important from the viewpoint of resource conservation and environmental protection. In recent years, application of pulsed power technology to the recycling field has attracted attention. The authors have been investigating on metal and plastic separation from optical discs using pulsed power. In this study, CD-ROM was...
At the EPURE facility, in France, a high power electron diode is used to generate an intense high quality pulsed electron beam in order to produce a bremsstrahlung radiation pulse for flash radiography. For this purpose, a cold cathode is driven by a 75 Ω graded transmission line, which delivers a 3.8 MV, 95 ns (FWHM) high power electrical pulse across a diode gap of 17.2 cm. The cathode is...
The conception of creating a mobile radiographic complex based on ironless pulsed betatrons is proposed for radiography of dynamic objects having large optical thicknesses. Realization of this conception allows: a) optimizing of a geometry of the hydrodynamic experiment at the expense of the radiation source and recorder position relatively to the test object, located in the explosion-proof...
Electric pulses (EPs) are well established for manipulating both the plasma and intracellular membranes depending upon pulse duration. Conventional electroporation uses EPs with durations on the order of microseconds to milliseconds. While submicrosecond EPs can manipulate intracellular structures, they still induce membrane nanopores that can allow ion transport [1]. Recent studies have...
The research of nanosecond repetitive pulsed discharges has received extensive attention [1-2]. It is valuable to study on gas discharges under the airflow, as well as flow control, discharge mode, etc. In this paper, we are focus on the discharges under motion law of charged particle of nanosecond pulsed discharges in the vortex flow, applied voltages and repetitive frequencies.
FIG. 1....
In this paper, dielectric barrier discharges were investigated for nitric oxide removal in a cylindrical electrode configuration. Reactive species like O, O3 and OH were analyzed in various different NO, N2, O2 and H2O gas mixtures.
The mechanism of nitric oxide removal was found to be dependent upon the reactive species participating in the NO removal reaction. For a gas mixture of N2, O2...
This work presents numerical modeling of interaction between intense electron beam and target plasma in LIA accelerator. Well-focused electron beam hit tantalum target that causes producing of high-density target plasma. This plasma consists of electrons and ions of tantalum and different contaminations adsorbed on the target surface [1]. Because of negative potential of the electron beam,...
A numerical model using both electromagnetic and Monte-Carlo simulations is used to investigate the performances of a 1 MV LTD pulsed high-power accelerator [1]. Particle-In-Cell calculations were employed to examine the beam dynamics throughout the Magnetically Insulated Transmission Line which governs the coupling between the generator and the electron diode. Based on the information...
Dynamics of beam spot on high Z target is key quality factor of LIA radiographic machines [1]. To obtain direct observation of beam spot evolution during the LIA shot the experimental procedure with time resolution of tens of nanoseconds was introduced [2]. It based on pinhole camera and scintillator with segmented structure. In this report the measurements of beam spot dynamics on the 2 MeV...
With the wide application of power electronic technology in pulsed power supply, high frequency and high voltage transformer has become one of the research hotpots. Magnetic core materials such as Ferrite and Nanocrystalline have excellent high frequency performance. However, they are seldom applied to high power situation by the limits of its manufacturing process. Though Fe-based amorphous...
We consider an overheating instability of a thin (compared to the skin depth) conductor with respect to stratification at the stage when its resistivity rises up to an electrical explosion. Temperature perturbations under such conditions are shown to grow in proportion to resistivity. In the model, when resistivity is proportional to temperature, perturbations grow in proportion to temperature...
Electron beam (e-beam) generation in high power vacuum diodes results in anode and cathode plasma formation. It is well documented that expansion of these plasmas into the A-K gap can adversely affect diode performance during the main e-beam pulse. However, ionized gases may exist for many microseconds afterward and can contribute to localized breakdowns in the diode gap if transient voltage...
Surface plasma formation processes in fast rising (≈ 100 ns) megagauss magnetic fields are interesting from the viewpoint of various applications. If the magnetic field penetration depth is lower than conductor thickness, the plasma formation should be attributed to so called skin or ultrafast electrical explosion. The dense plasma is formed due to Joule energy release when the magnetic field...
Pulsed plasma thrusters utilizing solid propellants have relatively low efficiency [1]. As alternative propellants, liquids are considered to be used in PPTs. However, using of liquid arises the problem of supplying it to the discharge area [2]. This work presents the results of the estimation of plasma formation efficiency of the discharge unit utilizing vacuum pump oil as a propellant. It...
Underwater pulsed spark discharge has been proposed to rehabilitate the clogged wells in the ground water intake system in recent years. It has been proved that the shock wave developed in the surrounding water by the rapid expansion of the spark channel efficiently eliminates incrustations on the well screen. Of the various well structures, horizontal wells are practically important as they...
In order to be able to propose a dual pulse accelerator for future flash X-rays capabilities, a preliminary design of a high current induction injector has been developed. This design is based on the use of dual pulsed power generators actually available in the lab. The architecture, the number of cells needed and the dimensions of the conductors are evaluated with the hypothesis of using...
*The Proton Power Upgrade(PPU)project at SNS is planned to accelerate 38mA of beam current to 1.3GV, effectively doubling the accelerator power capability to support the planned Second Target Station. This project required three additional modulators to power the 28 additional 700kW klystrons and associated high beta cavities. An alternate topology high voltage converter modulator (AT-HVCM)...
The pulse forming networks (PFN) were developed to provide a 2 kA, 20 MeV linear induction accelerator cells power supply. A PFN’s and high-voltage capacitors manufacturing is organized at BINP. The PFN is a LC-network with nonuniform impedance made of capacitive sections with a combined paper-film dielectric filled with a castor oil in a polypropylene case. A PFN’s isolation is rated at 50 kV...
The 1st radiographic axis of Epure, shared French and British facility, is a linear induction accelerator, a complex system with parts standing out as more critical. Those parts are tested and calibrated on dedicated benches. Two such benches are described here.
The beam evalauation is essential to the right performance of the whole machine. To have good quality assessment of beam relevant...
Soft x-ray radiography (≈ 1÷2 keV) of a bismuth and aluminum metal-puff plasma formed by the high-current vacuum arc discharge is presented. The plasma gun with the arc current ≈ 60 kA and the current rise time ≈ 7 μs was used to produce a metal-puff plasma jets. The compact pulsed radiograph XPG-1 (250 kA, 220 ns) with X-pinch and PZ-pinch load was used as a source of the soft X-ray...
The energy of the electromagnetic railgun comes from the pulse power which has ability to adjust parameters, furthermore, it can adjust the armature velocity in bore.
The electromagnetic force of the traditional railgun is easy to be obtained by relying on the relationship between the inductance gradient and the current, however, the electromagnetic force of the augmented railgun is not able...
Dielectric Wall Accelerator (DWA) is a new type of pulsed linear accelerator. Its working mechanism is regulating the discharge order of different power sources to keep the accelerating electric field present near the particles all the time, and it is really suitable for heavy ions acceleration. The Institute of Fluid Physics, China Academy of Engineering Physics (IFP, CAEP) began the research...
This paper demonstrates experimentally recorded peculiarities of a dynamical Z-pinch powered with the current from a magneto-cumulative generator. The overmass load represents a cylindrical multiwire array consisted of 680 tungsten wires of diameter d=11 µm and length l=1.5 cm (total mass M=4.14 mg). The wires were evenly located on a cylindrical surface of the radius R=3 cm. Maximum...
The natural rubber research is ongoing project at the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The project aims to use electron beam irradiation for high quality vulcanization process for natural rubber. The main accelerator system consists of a DC thermionic electron gun, 5-cell linear accelerator structure, control system, RF system and electron beam...
A high dielectric, nanodielectric, composite material, MU100, was originally developed by the University of Missouri for use in dielectric loaded antennas. Based on its material properties, dielectric strength and losses, it was determined that MU100 had possible uses in the development for high energy-density capacitors.
This paper presents the dielectric properties of the materials under...
*NSTec product number: DOE/NV/25946--3117
After the 1992 moratorium on underground nuclear testing, the Subcritical Experiment (SCE) program was initiated to support stockpile stewardship. The SCE laboratory is located in a tunnel complex 1,000 feet below ground surface at the Nevada National Security Site (NNSS). Cygnus is a radiographic x-ray source which is a primary diagnostic for the SCE...
A pulsed system for a 2 kA, 20 MeV linear induction accelerator power supply was developed. On a first stage of operation it is capable of producing a 336 kV, 2 kA, 60 ns single pulse at the accelerating inductive cells. Each cell is supplied by 8 pulse modulators based on an inductive voltage adder principle. Each modulator is designed to produce pulses up to 21 kV, 10 kA with a different...
In the ALT-3 driver design – with a 0.4-meter-diameter disk explosive magnetic generator and an electrically exploded opening switch – load currents can reach 70MA, which is high enough for driving a 3-mm-thick Al liner having a radius and a height of 4 cm to 20 km/s at an impact radius of 1 cm. The azimuthal magnetic field on the liner in this case grows to 6MG (magnetic pressure, up to 1.4...
In this work a description of behavior of ferrite-loaded coaxial lines is carried out by solving the gyromagnetic magnetization equation for the ferrite coupled with the Maxwell equation for transmission line in time domain. The influence of induced radial and axial magnetic field components in the ferrite magnetization is investigated as well the rise time of input high voltage. The model is...
Measurements are presented of the current per unit length as a function of time and transverse distance from the center of a water-tamped 80 µm thick Al foil as it explodes into warm dense matter by Ohmic heating. The foil width narrows smoothly to a central width of 15.2 cm, across which the measurements take place. Current is delivered from a 36 µF capacitor bank charged to 30 kV and...
Today, the efforts of scientists to solve problems of fusion associated mainly with magnetic systems, primarily with tokamaks and etc. One of alternative method is plasma focus (PF) installations, based on the focusing of the plasma beam in a small area with high density. Using of coaxial pulsed plasma accelerator equipment, the authors had aim of creation of focus reactor with current...
The addition of nanoparticles with conducting and semiconducting properties to liquid and solid insulation systems is a current area of active research interest. In liquid insulation the nanoparticles have been shown to improve the breakdown strength of certain liquids due to their ability to scavenge free electrons from the system. In solid nanocomposites improvements in the physical...
The capillary based pulsed plasma thruster has a huge potential in the small satellite application. It features with higher overall efficiency in low energy level beyond the advantages of traditional pulsed plasma thruster. The typical physical process of the thruster mainly includes discharge, ablation and thrust production. The discharge characteristic reflects the energy transfer efficiency...
The work deals with obtaining the high pulsed power in the high-current plasma diode. Under certain conditions in the diode, the space charge electric double layer is formed in the current-carrying plasma. Almost all active discharge voltage focuses on it. The powerful electron and ion beams accelerated in the layer can be used both for the solid surface treatment, and for the plasma heating....
Pulsed power discharge in water has been investigated as one of advanced water treatment technologies. Pulsed power discharge in water generates many active species (ozone, OH radical, ultraviolet rays etc.). All of them could be utilized to the decomposition of organic substances in water. However, since the lifetime of OH radical is short, there is a problem that it reacts and disappears...
Under the conditions of sub-microsecond pulsed dielectric barrier discharge, the ozone production yields depends on many characteristics. In previous papers, researchers focus mainly on voltage, frequency, gas flow rate, oxygen concentration, temperature and pressure which may not help the physical dimension design of the reactor, especially for length of the discharge gap, material and...
ABSTRACT:A high-current pulse generator of 112.5kJ capacitor bank has been developed for electromagnetic pulse welding. It made up of six paralleled 18.75kJ modules, every module is mainly made up of four paralleled capacitor and a trigger vacuum switch. The high-current pulse generator has been designed and fabricated for maximum operating voltage of 25kV, peak current of 1MA. Using a...
Irreversible electroporation (IRE) is a novel tumor ablation technology. Now it has been used by clinicians for several trials. The clinical trials showed that the effect of the IRE is greatly limited by the inadequate treatment planning. The outcome of IRE depends on the effective electric field distribution in tumors. In order to analyze the effect of real tumor ablation by irreversible...
Linear induction accelerator LIA is designed and developed at the Budker Institute of Nuclear Physics in 2010 year as injector for fullscale radiographic machine. Now it is currently used as independent radiographic X-ray source for testing objects with an optical thickness up to 70 mm lead equivalent. In 2014 year the high-voltage power supply system was upgraded. Accelerator operates in one...
Pseduospark switch, as a kind of low-pressure cold cathode gas switch, has broad application prospects and was studied for more than 30 years. Few researches reported the abnormal discharge in the switch which happened frequently in experiments. In our experiments, different from the hollow cathode discharge, three abnormal discharge modes, cathode sidewall to anode sidewall, cathode sidewall...
Implosion of quasi-spherical wire arrays opens the possibility of more efficient use of the kinetic energy of the material being compressed to create a source of soft X-rays (SXR), compared to two-dimensional compression in the case of a cylindrical wire array. This is due to the contribution of the kinetic energy of the axial movement of the plasma into the internal energy of SXR source. An...
Abstract: A new triggered vacuum switch ( TVS) was designed and tested . The TVS was successfully tested up from 500V to 10kV peak charging voltage. Compared to other typical switches, the tested switch showed high reliability of trigger voltage, trigger current. The TVS is used for a high-current pulse generator of 112.5kJ capacitor bank, which has been developed for electromagnetic pulse...
The energy deposition plays an important role in the study of the thermal mechanical effect of intense electron beam. A new method to obtain the time-dependent electron beam energy deposition at different anode target position was presented. First, the electron beam energy should be discretized according to diode working time（every 5ns）, so that the electron beam in each time period is...
When solid armature moves along rail at high speed, the thermal effect will destroy good contact between armature and rail in the process of electromagnetic rail propulsion. It has a lot of damage to rail, and which will affect launching’s precision and efficiency. In this paper, the simulation, measurement and characteristic analysis of the contact surface temperature are carried out for the...
A transmission-line-circuit model of the Z accelerator has been developed to aid in the design and analysis of experiments conducted on Z. The circuit model is based on the Bertha circuit code. Transmission line elements are used to represent Z’s 36 pulse-forming modules, water convolute, vacuum insulator stack, outer magnetically insulated transmission lines (MITLs), vacuum post-hole...
In order to prevent uncontrolled beam losses in the Super Proton Synchrotron (SPS) at CERN, which can cause thermal and radiation damages to machine components, an internal beam dumping system is used. It consists of three fast pulsed magnets which deflect the circulating beam vertically onto an absorber block within one accelerator revolution. The excitation current for each magnet is...
Recently, demands on high-coherent, ultra-bright, and ultra-fast X-ray photon beams are increased for an ultra-fast basic science applications. The pulse-to-pulse stability of RF linac klystron modulators is one of critical issues in 3rd generation synchrotron machine for the top-up operation of the PLS-II linac. This machine requires highly stable RF sources with a stability of 0.01% rms, to...
Magnetically driven implosions on the Z Facility assemble high-energy-density plasmas for radiation effects and ICF experiments. MDIs are hampered by the Magneto-Rayleigh-Taylor (MRT) instability, which can limit achievable stagnation pressures and temperatures. The metallic liners used in Magnetized Liner Inertial Fusion (MagLIF) experiments include astonishingly small (~10 nm RMS) initial...
In the past few years, we have developed two approaches for creation of electronically controlled RF radiation beam steering: the first one is based on two- and four-channel gyromagnetic nonlinear transmission lines (NLTL) operating at the GW power level, which represents decimeter wavelength RF sources of nanosecond pulses and the second approach is based on Cherenkov superradiance two- and...
RoHS regulations (i.e. prohibition of Mercury) have created a need for suitable replacements of legacy tube-based high power discharge switches like Spark Gaps and Ignitrons. Silicon Power now introduces solid state discharge solutions with: favorable performance to legacy products, longer usable lifetime and the ability to comply with RoHS.
Silicon Power’s underlying technology, Solidtron,...
Underwater electrical explosion of an Al wire can be accompanied by an exothermic process resulting in additional energy transferred to the generated water flow. Here, we report on recent results of a comparison between underwater electrical explosions of single Cu and Al wires. Experiments were carried out using a high-current pulse generator (70 kV, 40 kA, 100 ns). Using fast frame and...
Nowadays gyromagnetic nonlinear transmission lines (NLTL) have been studied with great interest [1] since they can generate RF up to frequencies up to 2-4 GHz at high power (hundreds of MW) as demonstrated recently [2]. As they are all solid-state devices, they can be used as compact RF sources. On these devices, microwaves are induced by the damped gyromagnetic precession of the magnetic...
The well-known effect of delayed impact-ionization breakdown manifests itself in 100-ps avalanche switching of Si or GaAs diode p+-n-n+ structure that is triggered by a steep voltage ramp [1-3]. Here we report first experimental observations of delayed impact ionization breakdown in Si and ZnSe semiconductor structures that do not contain any p-n junctions.
Si n+-n-n+ structures with the...
Recently, the concept of the preconditioned wire array Z-pinch was proposed in which the ablation phase was suppressed and the implosion involved all mass of the array. On MAGPIE facility, this was achieved for aluminum wire array by the employing a specially designed two stage wire array, which allowed the generation of a short prepulse current through the wires of the top imploding array,...
The US Naval Research Laboratory (NRL) has constructed a pulsed power system designed to operate with batteries as the exclusive source of input electrical energy. Each capacitor bank uses 192 lithium-ion batteries in series with a custom DC-DC converter to charge the capacitor to 5 kV in approximately 10 seconds. For now, the capacitor is being discharged into a resistive load through an...
We report on initial shock physics experiments performed on the MACH – Mega Ampere Compression and Hydrodynamics – facility at Imperial College London.
The MACH generator is a 2MA, 400ns, 100kV ‘dry air’ Linear Transformer Driver cavity, which can be readily expanded to higher currents and drive voltages. The generator was designed for ease of use, and rapid turnaround with a load region...
Recent advances in silicon carbide (SiC) device process, fabrication, design, and packaging have made possible the development of single die, high voltage Insulated-Gate Bipolar Transistors (IGBTs) and Junction Barrier Schottky (JBS) diodes with avalanche breakdown voltages up to 27 kV and 15 kV, respectively [1-2]. SiC power semiconductor devices fabricated on wide epitaxial drift regions...
A high-power semi-insulating GaAs photoconductive semiconductor switch (PCSS) with quantum well structure was fabricated. The AlGaAs layer was deposited on the surface of the GaAs material, and the reflecting film and the antireflection film have been made on the surface of the GaAs and AlGaAs, respectively. When the prepared PCSS worked at a bias voltage of 9.8 kV and triggered by a laser...
In the majority of applications for e2v’s direct-switched solid-state modulators, the modulator is connected to the magnetron with a short length of cable. This colocation of modulator and magnetron imposes very little pulse distortion and yields a high-quality, flat current pulse with good RF fidelity.
Typically, the modulator output cable is not rated for the full operating voltage of the...
With the progression of silicon carbide (SiC) technologies, single semiconductor switches with higher voltage and current capabilities are emerging. Evaluating the pulsed current capability of SiC semiconductor devices for pulsed power and power electronics applications is required to understand their performance and reliability. This paper presents the narrow pulse evaluation of 15 kV SiC...
Recent results on implosion of strong shock wave (SSW) generated by underwater electrical explosion of a spherical wire array are presented. Microsecond pulse generator (≤38 kV, ≤380 kA, rise time ~1.3 µs) was used for explosion of Cu and Al arrays with radii of 20mm, 25mm and 30mm. A strong light emission from water in the vicinity of the array origin was used to determine the SSW...
The Cygnus Dual Beam Radiographic Facility includes two identical radiographic sources - Cygnus 1 and Cygnus 2. Cygnus is the radiography source used in Subcritical Experiments (SCEs) at the Nevada National Security Site (NNSS). The machine specifications are: Electric - 2.25 MV, 60 kA, 60 ns; Radiation - 4 Rad, 1 mm, 50 ns; Operation - single shot, 2-shots/day. Cygnus has operated at the NNSS...
The availability of a high-power radiofrequency (RF) source above 200 GHz would introduce a remarkable progress in many applications, as in nuclear fusion plasma heating and diagnostics, in high-gradient accelerators, in RF undulators.
For this reason, ENEA is running a project for the realization of a Cyclotron Auto Resonance Maser (CARM).
The operational parameters of the CARM were selected...
We report on the development of fast high-voltage kilo-ampere thyristor-based switching modules, which can be easily scaled by means of series connection of the thyristors. The thyristors are in each case getting triggered by the overhead ignition of breakover diodes, with the anode of the breakover diode being connected to the anode of the thyristor and the cathode of the breakover diode...
Although many high-voltage pulse modulators for high-power pulse klystrons use thyratrons as a high voltage switch device, their instability and short lifetime are headache for large accelerator facilities including the X-ray free electron laser facility SACLA (Spring-8 Angstrom Compact free electron LAser). In SACLA, 78 klystron modulators for an 8 GeV linac are operated as high-power rf...
We investigate the effects of an axial magnetic field ($B_z$) on the current distribution in imploding plasma and the efficiency of the $B_z$-field compression by the imploding plasma. In the experiment, a cylindrical argon gas puff, in which is initially embedded quasi-static magnetic flux (up to 0.4 T), prefills the volume between two electrodes. Subsequently, a pulsed-current (rising to 300...
Diversified Technologies, Inc. has introduced a new series of AN/TPS-43/70/75 transportable radar transmitter upgrade kits that replace all outdated components with solid-state components.
DTI PowerMod™ transmitter upgrade kits deliver a complete solid-state modulator to replace the thyristor, trigger amplifier, regulator, pulse forming networks (PFN), pulse transformer, SF6 tank, and oil...
Development of the technology of using a vacuum arc discharge system for the formation of the metallic gas puff is going in two directions.
The first direction is the use of a plasma jet for the X-ray radiography. We have compared the spatial dimensions of the radiating hot spot based on the use of X-pinch and Point Z-pinch (PZ-pinch is a regular Z-pinch with a small initial size (diameter...
Key requirements for a solid state switch in a fast switching pulsed power circuit include high blocking voltage, high current conduction and fast switching. The wide bandgap properties of silicon carbide has enabled the development and commercialization of high voltage MOSFET whose steady state and transient characteristics meet the requirements for narrow pulse width applications. Even...
While the Z Facility can routinely deliver 25-27MA current pulses to a variety of high energy density physics experiments, load configurations which require high-inductance (>3.0 nH) hardware typically suffer from reduced current coupling in the form of charged particle losses in magnetically insulated transmission lines (MITLs). These losses: (1) can be difficult to model with conventional...
By adopting Marx generator technology,a compact repetitive pulsed power system has been developed which consists of a repetitive power supply and a Marx generator.By utilizing multiplex inverter boost-doubling rectifier circuits to operate in parallel,we designed and tested a repetitive power supply which can transform 30V DC to 100kV DC and charge the capacitor to 100kV repetitively.The Marx...
This presentation will retrace the author’s ~40-year journey to transform pulsed power machines into plasma physics experiments for the purpose of educating students in research. Early experiments on electron beam instabilities (ion-hose, beam-breakup-instability), relativistic gyrotrons, magnetrons and recent Recirculating Planar Magnetron (RPM) experiments utilized an Marx-Abramyan generator...
Breakdown voltage (BDV) is calculated for two electrode structures, namely sphere and donut gaps, operating in air at atmospheric pressure. The calculation is based on the streamer breakdown criterion. Comsol software is used for field analysis and calculation of critical number of electrons by assessing integrals of the efficient ionization coefficient along field lines. Thus, also lengths of...
Based on the controllable plasma layer turn-on principle, RSD(reversely switched dynsitor) has low dissipation and high di/dt capability. It is a special kind of semiconductor devices applied in the pulsed power area. Due to the advantages of small volume, low parasitic parameters and high reliability for the integrated modules, similar to the power electronic area, the integration trend has...
Epure is a shared Franch and British hydrodynamic experiment facility, in use since 2014 with one radiographic machine, previously called Airix and installed in a former French facility.
This linear induction accelerator has been moved and refurbished over the course of years 2013-2014, and operated with success and reliability since then. Sprecial care has been given to maintenance...
The direct solution of Boltzmann kinetic equation is of great interest for theoretical investigations of various gas discharges. Such approach is known to be the most fundamental because it gives comprehensive information about the discharge and its evolution by providing electron and ion distribution functions for any given time point. The complete numerical solution of Boltzmann equations...
X-Ray flash radiography is a useful diagnostic to investigate the structural response of matter under impulsive loading during hydrodynamic experiments. In addition to multiple axis capability, multiple pulses design for future upgrade of LIA machine(s) is under investigation at CEA. The major design changes of a dual-pulse LIA compared to the existing and operational one at EPURE (ex-AIRIX)...
Benefiting from solid-state pulsed power system with GaAs-PCSS, dielectric wall accelerator (DWA) as a new kind of high acceleration gradient accelerator has a compact construction that makes it quite suitable for some certain applications, such as proton tumor treatment and industrial inspection. The solid-state pulsed power system is made up of several groups of pulsed power units. Each...
Lithium-ion batteries are being more widely utilized as the prime power source of rep-rate pulsed power systems. Battery open circuit potentials as high as 1 kV have been proposed for use in naval shipboard power architectures. While this potential may not seem that high to engineers within the pulsed power and/or high-voltage power system communities, it is significant and must be designed...
It is well-known that underwater electrical wire explosion (UEWE) is accompanied by generation of strong shock waves (SSW) with fast front and short duration, which makes it attractive for various scientific and technological purposes. In this paper, a device for UEWE was developed and composed of pulse capacitors (200μF, 1~6kV), a spark gap switch, and a metal wire immersed in a chamber...
One of the original drivers behind the development of pulsed power was the need for short-pulse (flash) x-ray sources for hydrodynamic tests. These systems continue to be an important diagnostic for the evaluation of hydrodynamic phenomena. In the United States, three primary facilities provide this function: Flash X-Ray (FXR) at Lawrence Livermore National Laboratory (LLNL); the Dual Axis...
Pulsed electric fields (PEF) technology is an innovative non-thermal pasteurization method by using the high electric field (more than 20 kV/cm) and short duration (ns to ms) pulses to inactivate microorganisms and enzymes with only a small increase in temperature. In accordance with the aforementioned working principle of PEF application, a repetitive high power solid-state switch with high...
We are presenting an innovative space plasma generator, using explosive-driven flux compression generators to convert explosive chemical energy to electromagnetic energy. We will then use a Joule heating to heat up light metallic load in a sub millisecond time scale to transform the load from a solid metallic state to a first ionization plasma state going through multi-phase transitions to...
The MERLIN accelerator being commissioned at AWE in a new Technology Development Centre will provide one of the flash radiographic sources at a joint UK/French facility for hydrodynamic testing in support of the two nations' nuclear deterrents. The ten module Induction Voltage Adder (IVA) has been designed to provide a 60 ns long TerraWatt pulse to drive a Self Magnetic Pinch (SMP) electron...
The lack of availability of small, fast, switches such as krytrons ( e.g. EG&G KN 6) and thyratrons (e.g. E2V FX2530) makes the design of high voltage spark gap trigger units problematic. This paper will describe a 100kV trigger generator which is switched using a high voltage, high current IGBT switch. A capacitor, charged up to 5kV, is discharged with the IGBT into the primary of a high gain...
We report on the design of a compact and repetitive pulsed e-beam source. This pulsed e-beam source, which can work stably for long time, was built based on Marx technology. The designed output voltage, current, pulse width and repetition frequency of this e-beam source is 1 MV, 20 kA, 180 ns and 1~50 Hz, respectively. In contrast, the volume and weight of this source is limited to 2.5 m3 and...
Intensity-dependent nonlinear light absorption in bulk 4H-SiC at the above-bandgap energy of 3.49 eV (λ=355 nm) is studied. Characterization and understanding of such nonlinear optical behavior in 4H-SiC forms the basis of efficiency improvements and design of optoelectronic SiC devices, including photo-conductive semiconductor switches. It is noted that previous research performed elsewhere...
In the capacitive pulsed power supply, several or even hundreds of capacitors are in parallel to provide energy. If internal short circuit occurs in one of the capacitors, the others will inject a lot of energy into the fault one, which may cause a severe accident. By taking a shunt capacitor bank composed of ninety-six 33kJ-capacitors as the research object, a scheme which tries to protect...
A fast semiconductor-based Marx-generator is currently under development at the Institute for Pulsed Power and Microwave Technology (IHM) as driving pulse power source for a pulsed electron beam device (GESA). Its design addresses the challenging requirements of multipoint explosive emission cathodes such as fast voltage rise times below 100 ns together with flat top pulse amplitudes of 120 kV...
Both intense pulsed X-ray and repetitive pulsed X-rays play an important role in the investigation of various physical processes in hydrodynamic experiments.
In order to generate intense pulsed X-ray, 1.2 MV pulsed power generator and rod-pinch diode are designed and constructed at Institute of Fluid Physics, CAEP. The generator is composed of a Marx generator, an upstream oil line, a pulse...
Michael G. Mazarakis, Mark L. Kiefer, Joshua J. Leckbee,
Sandia National Laboratories
Albuquerque, NM 87185
Del H. Anderson, Frank L. Wilkins, Robert J. Obregon
National Security Technologies
We have constructed a Component Test Stand (CTS) to test various high voltage components to be utilized in near future pulsed-power devices. In addition to cable and oil feed-through design voltage...
Long pulse intense electron-beam accelerators (IEBA) are of great interesting in many regions. In this paper, a folded IEBA is introduced. The pulse forming section of the IEBA is made up of two pulse forming lines (PFL) and a curving transition section to joint two PFLs together. This type of IEBA is compact in structure. The flat voltage of the main pulse on the load of IEBA is one of the...
A study is carried out on a uniformly contaminated cap and pin insulator string consisting of 10 glass discs, using a Finite Element Analysis software. A CAD design of the insulator is such that a thin conductive water layer covers the entire glass region. This water layer represents acid rain. 150µS/cm conductivity is applied to the water layer to represent an approximate 5% concentration of...
Initial experiments have been conducted with a new model of the LANL Ranchero magnetic flux compression generator (FCG) that has been introduced as the Ranchero-S configuration. The design overcomes a weakness in the earlier versions related to possible flux pocketing near the output glide plane when currents become very high. In addition to employing an armature that is sculpted to match a...
The Dual-Axis Radiographic Hydrodynamic Test (DARHT) facility at Los Alamos National Laboratory (LANL) uses two, linear-induction accelerators (LIAs) for flash, x-ray radiography of hydrodynamic tests. The Axis-I LIA uses a single, beam pulse of 60 ns, 20 MeV, and 2 kA. The Axis-II LIA uses a long beam pulse, and a kicker to generate four radiation pulses.
The National Nuclear Security...
Photoconductive semiconductor switches (PCSS) made from bulk, semi-insulating GaN have been fabricated and tested under pulse-charged conditions. Switching response and photocurrent efficiency of GaN PCSSs triggered by sub-10 ns, 355 nm laser pulses is reported. It is shown that fast rise time (<300 ns) voltage pulses can be used to charge a GaN PCSS to fields well beyond the DC breakdown...
There is a strong demand in the power and pulsed power industries for environmentally friendly insulating gases and liquids with advanced dielectric properties as a replacement for SF6 due to environmental concerns. Recently several novel dielectric fluids have been proposed for potential use as insulating materials. 3M has developed the fluoroketone Novec™ 5110 dielectric fluid as a possible...
This paper is concerned with use of partial discharge monitoring to provide information about the condition of the insulation of electrical cables used for HVDC transmission systems. Electrical cables are among the most fundamental components of any electrical grid, from large subsea international interconnectors, to the ‘last mile’ providing consumers with their electrical supply. The size,...
The Department of Energy has tasked a few of the national laboratories to design and develop a new linear induction accelerator (LIA) capable of multi-pulse operation. This LIA would be different from the DARHT Axis II design in that, instead of multiple pulses being ‘kicked’ out of a single long pulse, the multiple pulses will be delivered independent of each other by the pulsed power system....
Nonthermal plasma has been used as a successful treatment method for melanoma cancer cells. There are a number of power sources used to generate the high voltage signal required to create nonthermal plasma. The RF plasma jet uses a resonance transformer to generate a low frequency sinusoidal voltage. The pulsed DC plasma jet uses a high voltage pulse circuit to generate a low frequency square...
The Z pulsed power driver at Sandia National Laboratories is used for a wide range of high energy density physics experiments in areas such as inertial confinement fusion, radiation effects, and dynamic material properties. Experimental demands are pushing for the highest energy attainable with more reliability and precision in timing and pulse compression. A previous version of the...
High pulsed magnetic field, particle accelerator, strong laser, electromagnetic emission and other pulsed power system require capacitive energy with short duration and high density. It is necessary to recharge the capacitor to specific voltage by capacitor charging power supply after the discharge of energy stored in the capacitor. Charging power supply applied in high power capacitive pulsed...
Pre-fire problem in the abort kicker system have been last for a long time during the past 17 years of operation in RHIC. In order to limit the number of pre-fire events, a new system is implemented, installed and tested pre start of Run 17. We have installed two new Relay Control Units into the RHIC abort kicker system, one in Blue Ring and one in Yellow Ring. The scheme is included a simple...
We are testing a new radiographic source that uses a Marx bank with a one microsecond discharge time, coupled through a plasma opening switch (POS) to a plasma-filled rod-pinch diode (PFRP). The Hawk generator at NRL contains four Marx banks connected in parallel with an erected voltage of 640 kV and an output current of 700 kA with 1.2 microsecond quarter period into a short circuited 600...
At Wuhan National High Magnetic Field Center, a 100 MVA/100 MJ pulsed generator and two 67.5 MW converter modules have been installed as power supply for pulsed magnets. This power supply can energize magnets alone or with other power supplies. Long-pulsed magnetic field with 50 T/100 ms flat-top has been produced, and 100 T pulse magnetic field is under commissioning. In those high power...
Multi-channel transient electromagnetic (MTEM) is an artificial source electromagnetic detection method, the transmitter injects the high-power pseudo-random binary sequence (PRBS) signals with different coding frequencies into the earth to obtain the geological structure and the mineral resources. A novel active soft-switching converter with loss-less snubber for MTEM transmitter is presented...
A huge inductor filter becomes essential when capacitor charger which has capacitive characteristics is implemented based on the series-parallel resonant converter. This paper described anaysis, design and test results of the series-parallel resonant converter which operates as a constant current source on above resonance without inductor filter for use in high voltage capacitor charger...
Pulse forming networks (PFN) and charging lines are widely used in pulse power techniques for high voltage pulses generation and shaping. Usually PFN should be precharged to the double voltage (energy is stored in electric field) and is used in combination with high voltage closing switch. A lot of theoretical and experimental researches with different types of PFN-based circuit design have...
The rock fracturing technology can effectively enhance the permeability, the flow conductivity, and the production of oil and gas. Hence, in order to research the fracturing effect caused by the high voltage large current, a repetitive pulse power supply (RPPS) is developed. The RPPS is mainly composed of a repetitive charging power supply, energy storage capacitor, discharging switch and...
Food process engineering aims to create new products with improved quality to satisfy increasing consumer demand for fresh and healthy products [1,2]. To fulfill the expanding consumer demands for foods with higher nutritional value and “fresh-like” taste, novel technologies, such as pulsed electric fields (PEFs), are currently under investigation to replace conventional thermal processes...
This paper describes the software changes made to the data processing and display system for HERMES III accelerator at the Simulation Technology Laboratory (STL) at Sandia National Laboratories, New Mexico. The HERMES III accelerator is a gamma ray simulator producing 100kRad[Si] dose per shot with a full width half max pulse duration of ~25 nanoseconds averaging six shots per day. For each...
Beam breakup instability (BBU) is an important factor dominate the design of induction cell for high intensity linear induction accelerator. In this study, we optimize a magnetic tune for a conceptual induction accelerator. By using BREAKUP code and optimization algorithm, we estimate how BBU would affect the final beam spot size.
Taiwan Photon Source (TPS) is the latest-generation 3-GeV synchrotron light source. Pulsed power supplies to control injection and extraction of the TPS pulsed magnets have been designed and implemented. The experimental physics and industrial control system (EPICS) embedded programmable logic controllers (PLCs) were developed to control the pulsed power supplies. The control interface is...
The China Spallation Neutron Source (CSNS) accelerator is designed to accelerate proton beam pulses to 1.6 GeV at 25 Hz repetition rate, striking a solid metal target to produce spallation neutrons. The accelerator provides a beam power of 100 kW on the target in the first phase [1]. The linac is designed with beam energy of 81 MeV and a peak current of 15mA. It consists of RFQ, two bunchers...
To eliminate the common mode signal, the new magnetic probe (B-dot) is employed with balance design with two loops wired at opposite direction. The magnetic probe is capable of measuring signal up to 150Mhz, we will present the design details and calibration procedures.
Design, implementation and experimental results of a 3-phase series-parallel resonant type high voltage capacitor charger which is operating as a constant current source at a specific switching frequency are described. The operating principle of the capacitor charger as the variation of an input-to-output voltage gain is explained. Several current gain curves as the variation of...
The high voltage pulse power supply is the important components in HL-2A tokamak device which provide the direct-current (DC) energy to auxiliary heating system. The high voltage pulse power supply is build based on pulse step modulation (PSM) in HL-2A. The performance of the PSM power supply control system will directly affect the result of the auxiliary heating system, including the study of...
Unlike other types of switches can be used in pulsed power, magnetic switch has not control gate. This means that the switching time is a function of load conditions, the source of the initial pulse, switch terminal voltage waveforms caused by these two and the switch design parameters. Considering the fact that the switch should be designed to suit the load and source and not vice versa, we...
We are developing a 30MJ high power pulsed power supply (PPS) system with 10kV operation voltage for EML research. The PPS system can be divided into several functional subsystems: pulse forming subsystem, control subsystem, charging subsystem, and measurement subsystem. Matrix type structure and modular architecture are adopted in the design of the PPS. The PPS is assembled in two 40’ general...
This paper describes the design of an active voltage droop compensator for solid-state long pulse modulator. For generating long pulse with low voltage droop, the active droop compensation technique provides advantages in terms of the high power density and low cost. The proposed
droop compensator required to generate triangular waveform consists of the resonant converter and the flyback...
As the development of pulse power technology, the pulse power supply modules (PPSM) are widely used in areas of scientific research, medical treatment, industry, military, and geological prospecting. In these areas, more and more energy is needed and the number of PPSM is increasing rapidly, and the accurate pule discharging waveforms are required in some applications. How to control so many...
The performance of induction accelerator relies greatly on the design of the diode injector. By using TRAK (ray tracing code) and AMBER (slice PIC code), we designed a 2KA/2MeV diode injector and beam transportation from position of cathode to accelerator exit. We will present some design optimization strategies for diode injector and simulation results from TRAK and AMBER, particle loading...
Of general interest to the scientific and engineering community is the development of facilities for testing, validation, and qualification of pulsed power systems, components, and assemblies. Naval Surface Warfare Center Dahlgren Division (NSWCDD) has a long history of designing and implementing facilities for testing pulsed power systems capable of generating, transmitting, and sinking...
Recently pulsed ion beam technology has been widely used for materials surface properties modification by the methods of ion implantation, ion plasma coatings deposition, and high energy ion beam energetic impact. For those materials processing applications, it is very important to develop the accelerator technology to generate ion beams with various ion species and high purity.
In order to...
A low impedance modulator made up of ceramic-loaded parallel-plate transmission line sections in a Marx configuration has been developed as a test bed for high power microwave sources. The generator has configurable impedance between 15 and 25 ohms, pulse-width between 50 and 200 ns, and can operate at repetition rates up to 100 Hz with a 200 kW high voltage power supply. The energy stored...
A pulse-operated penning plasma source has an instantaneous power of several tens of kilo-watts and an order of the current density of A/cm2 class, of which characteristics are similar to so-called HiPIMS glow plasma. The magnetic field is perpendicular to the target surface thoroughly and the plasma generation can be set arc-free and no-droplets. These characteristics are superior to the...
The Z machine is a high-current pulsed-power generator located at Sandia National Laboratories capable of delivering 100-ns, 30-MA current pulses to a variety of targets. Under certain conditions, however, a significant fraction of the current does not reach the load but is shunted across the inter-electrode vacuum gap that leads to the load. That undesirable current loss is believed to be...
Pulsed plasma thrusters (PPTs) have vast potential for application in small satellites. Capillary discharge, which produces high density and relative low temperature plasma, has a great interest in space propulsion devices. Based on the capillary discharge, PPTs make full use of electrothermal acceleration mechanism to promote the overall efficiency in low energy level.
In this paper, a...
National Security Technologies (NSTec) is developing dense plasma focus systems as intense pulsed neutron sources. Sandia National Laboratories participated in a limited number of experiments on an NSTec plasma focus. In collaboration with NSTec, Los Alamos National Laboratory, and Lawrence Livermore National Laboratory, we implemented additional electrical and X-ray image measurements in...
Velvet cathodes are widely used in field-emission electron diodes, in particular in induction accelerators used for flash X-ray radiography. The emision from velvet could be different from pulse to pulse in multi-pulse operation. As a consequence, we are revisiting the beam homogeneity and the emittance of the electron beam produced by velvet cathodes.
First, we used a single-pulse diode...
Ethylene is a gas released from fruits and vegetables and has the effect of promoting their growth. Today, fruits and vegetables of various types are transported together by container ship. However, ethylene release amount and product sensitivity toward ethylene depend on product type; thus, if product with high ethylene release such as apples are mixed with that with high ethylene sensitivity...
Field Effect Transistor (FET) controlled devices, such as MOSFETs and IGBTs, exhibit some desirable characteristics over other solid-state devices; benefits include high frequency switching, voltage control, and compact control circuitry. This paper details a testbed for evaluation of FET controlled devices used in inductive pulsed power systems as well as the diagnostics used to characterize...
Initial optimization of the Sandia National Laboratories Z accelerator has enabled the delivery of tens of MA’s of current to various load types. However, plasma formation in the vacuum magnetically insulated transmission lines (MITLs) is seen as one of the limiting factors in improving machine performance. It is believed that severe heating of the electrode surfaces, due to a combination of...
Due to their high saturation flux density, amorphous metallic alloys play a key role in linear induction accelerators that require ferromagnetic cores with sufficient volt-seconds to support multiple pulses. As both the shape of the material hysteresis curve and the core losses depend on the magnetization rate, dB/dt, measurements at various rates are necessary in any system model involving...
The results of research of heavy pulse current switches built on Light Triggered Thyristors (LTT) and pulsed diodes are presented. Transients in a semi-conductor switch are analyzed at a capacitor discharge in a Pulse Forming Network (PFN), which incorporates an inductor and crowbar diodes. Maximal currents for a semiconductor structure, at which thermo-generation peaks appear on oscillograms...
The ST-40 tokamak is a Spherical Tokamak designed and under construction by Tokamak Energy to reach the goal of producing clean energy by means of nuclear fusion. The tokamak machine consists of several high power magnets to confine and control the plasma inside the fusion chamber. These electro-magnetic magnets require very high currents, however the existing power infrastructure doesn’t...
Insulators that have suffered invisible damage can cause catastrophic system failure. Detection of the fault through visual inspection is not possible. An automated non-destructive test method is preferred. We have developed a system capable of a peak pulse voltage > 50 kV with fast rise time and limited pulse energy coupled with a high speed FPGA processor to analyze the output voltage and...
Introduction
When researching improvements to high power precision Electron Beam and Ion Beam performance power systems knowledge of High Voltage power quality terms, specifications, and key performance factors can be essential to selecting or improving the best available technology or for working with suppliers on specific needs. Examples of key High Voltage Power Supply elements...
Introduction:
When researching improvements to low power (30W to 250W average) pulsed power systems knowledge of High Voltage power quality terms, specifications, and key performance factors can be essential to selecting or improving the best available technology or for working with suppliers on specific needs. Examples of key High Voltage Power Supply elements resulting in performance &...
A discharge plasma under water is a promising candidate to reduce the risks of bacterial infection in a hydroponics culture system. In addition, the discharge plasma provides nitric acid into the solution, which promote plant growth rate. We developed a system using plasma under solution and the performance of the developed system was evaluated using tomato seedlings in the recirculation...
The Marx generator, also known as switched capacitor voltage multipliers, is one of the most used topology to generate high-voltage unipolar or bipolar pulses. The Marx generator is composed of n capacitors, charged by a parallel connection to the power supply and discharged to the load by a series connection. The connections are enabled using switching power semiconductors. Current...
Ethylene (C2H4) gas promotes the aging of some kinds of fruits and vegetables. Decomposition of C2H4 using non-thermal plasma is effective for keeping freshness of fruits and vegetables. In this paper, the influence of O2 concentration to C2H4 decomposition using a dielectric barrier discharge (DBD) was evaluated. The dual polarities pulsed voltage was generated using a pulse transformer...
Different diagnostic tools were installed at the facility GESA-SOFIE in order to investigate the plasma behavior in the cathode-grid gap. A high-resolution fast CCD camera was used to monitor the formation and evolution of the cathode and grid plasmas. A streak camera with high dynamic range delivered information on the characteristics of the plasma motion. A complex modification of the...
ABSTRACT
High energy density metalized film capacitors can be an enabling technology for pulsed power systems. High electric field stress (i.e. high voltage) is known to limit shot life on these capacitors from breakdowns through the thin film which reduces the capacitance. This is commonly referred to as the “self-healing” property of metalized film caps. Much research has been done to...
Transient magnetic diffusion through conductors of thickness comparable to the skin depth is investigated. Since an analytical solution is unavailable in this case, such magnetic diffusion results must be determined via simulation or experimentation.
In the experimental approach a sinusoidal current with peak values in the range of 20-30 kA (approx. 7 kHz ringing frequency) is pushed through...
Our team at Los Alamos National Laboratory has successfully employed Compton spectrometers to measure the x-ray spectra of intense radiographic sources, both continuous and flash. In this method, a collimated beam of x-rays incident on a convertor foil ejects Compton electrons. A collimator may be inserted into the entrance of the spectrometer to select the angular acceptance of the...
Electron multipactor is a major problem in accelerators, both in accelerating cavities associated with dark current and beam induced e-cloud problems, and in RF distribution systems leading to catastrophic damage or in mild cases performance decrease and phase shifting. In many scenarios passive mitigation techniques are preferred. Multipactor may be completely avoided if the effective SEY is...
In the design of pulsed relativistic accelerators, high power electrical pulses are generated in a volume that is filled with either high pressure gas or an oil to manage the high electric fields. However, the beam generating diode must operate in vacuum. The two sections, then, require an insulating barrier between them which is subject to very high electric fields. The vast majority of...
With the low cost, high resolution, good traffic and other characteristics, Helicopter Transient ElectroMagnetic (HTEM) system has gradually become a hot topic of Airborne ElectroMagnetic (AEM) survey. The multi-pulse large magnetic moment transmitting is one of its key technologies. However, a few topologies have been reported in the literature. The high-power multi-pulse current source...
Multiple pulse flash radiography has been implemented worldwide utilizing various methods for many years. In the past decade, the method for achieving multiple pulse flash radiography has focused on utilizing a Linear Induction Accelerator (LIA) as the source. Various techniques, including diode isolation$^{1}$, have been used to accomplish the multiple pulse function.
Los Alamos National...
The continued increase in overall energy demand and the desire to mitigate environmental hazards of emissions continues to motivate alternative energy source development. Initial studies focused on developing plant biofuels; however, this approach is expensive and used foodstuffs, raising food costs. Microalgae provide an alternative source of liquid fuels that is not involved in the food...
Dielectric Barrier Discharge type ozonizers has been used in water treatment, sterilization and deodorizasion for many years. However, the yield in ozone generation leaves a room to expand its utilization. On the other hand, ozone generation using nanosecond pulsed discharge has attracted attention as a high-yield ozonizer. However, maximum ozone concentration remains lower value than that...
Keywords:Coil,Design,Alloys,Service life, Magnetic Pulse
Abstracts
High magnetic field pulse, despite it's proven advantages,has still not been widely adopted in industrial applications-mainly because of critical parameter of work-coil's service life.
PULSAR's R&D works aimed to create suitable work-coils (Solenoids) for industrialuse are reported here. The material and geometry...
.
Traditional transformer design optimization is obviously inadequate,the main content of this paper that we should consider the high-frequency loss model, using the improved genetic theory, to achieve a fast and efficient multi-objective optimization method,and compared the result of the classic multi-objective optimal method and the NSGA II to get the most effective method which will...
Nowadays there are many topologies based on the Marx concept using power semiconductors devices as switches that are capable to generate unipolar or bipolar high voltage pulses. In some industrial applications such as water decontamination or liquid food processing, the use of bipolar pulses instead of unipolar pulses, has demonstrated an enhanced final product or industrial process. Generally...
The breakdown of insulation in cables while in service can cause considerable damage to equipment and the accessories to which it is connected. It has been understood that such failures may be related to the occurrence and severity of partial discharges. Protrusions are one of the most critical types of imperfection, and affect primarily the semiconductor shields. The effects are more severe...
Dielectric barrier discharge (DBD) is an effective way of producing homogeneous plasma. Plasma, a quasi-neutral gas, is referred to as the forth state of matter. Plasma surface treatment consists of plasma surface modification, plasma polymerization and plasma surface grafting. It is very applicable to modern continuous mass production of industry, and has a very broad prospect. Dielectric...
An atmospheric pressure plasma jets (APPJs) have been used for several years in a wide field of applications. APPJs are driven by sinusoidal wave of several tens of kilohertz. We have developed a surrounding gas-fed type APPJ to improve the selectivity of various feeding gases expecting production of ROS and RNS with a shielding effect from the ambient air condition. A newly developed APPJ...
Airborne transmission of infectious organisms is a major public health concern, particularly within healthcare and communal public environments. Methods of environmental decontamination utilising pulsed ultraviolet (UV) light are currently available, however it is important that germicidal efficacy against airborne contamination is established. This study demonstrates evidence of the...
With the development of high power microwave (HPM) technology and its transmitted power increasing from the level of MW to GW, dielectric window, as an important part of transmission and radiation system, is suffered with high gradient electric field, resulting in phenomena of surface flashover. Secondary electron emission yield (SEEY) is an important parameter determining build up of...
Power p-i-n diodes are well known for their high-voltage and high-current capability which makes it a viable candidate for pulsed power circuits. The breakdown mechanism of a p-i-n diode enables high blocking voltage capability whereas, conductivity modulation due to high level injection drastically reduces the ON-state resistance during high forward current. Even though it is possible to...
For massive conductors in case of sharp skin-efffect it is possible to define the skin-parameter, which does not depend on time and frequency and effects on transients in electrical circuits with massive conductors. In the paper the peculiarities of transients with massive conductors are described, the definition and justification of skin-parameter are presented, the methods it calculation and...
The Spallation Neutron Source (SNS) Proton Power Upgrade (PPU) will double the beam power from 1.4 to 2.8 MW by adding cavities in the superconducting linear accelerator (SCL) which will increase the beam energy from 0.97 to 1.3 GeV and by increasing the average Linac beam current from 26 to 38 mA. Provisions for an accelerator power increase were made in the original SNS project, and these...
The CERN CTF3 facility is being used to test and demonstrate key technical issues for the CLIC (Compact Linear Collider). Pulsed RF power sources are essential elements in this test facility. Klystrons at S-band (3GHz), in conjunction with pulse compression systems, are used to power the Drive Beam Accelerator (DBA). Most of the modulators that provide the electrical power to the klystrons use...
The characteristics of opening switch plasmas initialized by two methods—cable guns and gas-fed Marshall guns— were compared spectroscopically, as part of an effort to understand the effect of multi-species plasma composition on opening switch performance. Anecdotal observations of slower switching with single-species plasma sources compared to multi-species sources have led to the hypothesis...
LEETCHI is an electron source designed to produce 140 keV, 5 A, 140 μs beams at a repetition rate of 50 Hz. The shot to shot and flat top current stability of this drive beam injector for CLIC has to be better than 0.1 % and a normalized emittance of 14 mm.mrad is expected. A test stand has been build which allows to diagnose and dump the beam produced by a thermionic cathode. The thermionic...
Under the UK and France Treaties related to “Defence and Security Co-operation” and to “joint radiographic / hydrodynamics facilities”, the joint Hydrodynamics Research Facility knows as EPURE is under construction at CEA VALDUC in France. At present, this facility is fully operational using a single radiographic axis configuration . By 2022, two others high performance X-ray machines will be...
Liquid dielectric breakdown properties are studied towards the development of efficient intermediate storage devices for pulsed power applications. A Tesla based pulse generator along with suitable voltage (V-dot) and current (self-integrating Rogowski coil) sensors are indigenously developed. The experiments are performed by applying few 100 KV with few tens of nanosecond pulse under uniform...
Biofuel production as a sustainable source of green energy is considered as promising complements to petroleum in order to prevent environmental problems such as global warming. In this regard, microalgae can be one of the best options since other plant resources may be used for human consumption, using them for producing biofuel may cause an increase in their price. However, there are several...
ABSTRACT:
Pulse Transformers are used in pulse power generating system when Output Voltage is to be raised, to invert the polarity and provide a DC isolation between discharging source and Load with minimum loss of energy and maximum transformation efficiency. Among different kinds of high-voltage pulse transformers, Authors have studied Pulse Transformer with closed magnetic core. Studies...
Arijit Basuray1, Saibal Chatterjee2
1.NEO TELE-TRONIX PVT. LTD.(NTPL), Kolkata,India
email: abasuray@gmail.com
2.DEPARTMENT OF ELECTRICAL ENGINEERING,
NERIST (Deemed University),Arunachal Pradesh,India
email: saibalda@ieee.org
ABSTRACT:
Pulsed Power in the form of Recurrent Surge Generator (RSG) can...
The efficiency of the electromagnetic launch system depends on the electromagnetic energy which is converted into the kinetic energy of the projectile. The energy loss of electromagnetic rail launch system mainly includes electromagnetic loss, friction loss and aerodynamic loss. The aerodynamic loss may reach up to 10% of the system energy, and the higher the projectile velocity, the higher...
The surface flashover across the insulators is the major limitation of the performance for the high voltage system. Surface flashover voltage is mainly affected by the surface properties of the materials. Therefore, it has become an important technical means to improve the surface flashover voltage of insulation materials by a series of surface treatment technology. As a new material surface...
The insulating level of a pulsed-power system is usually limited by the voltage that initiates flashover over the surface of its solid insulators, rather than by the bulk solid breakdown strength. Due to environmental concerns, the use of SF6 is being reduced and it is therefore imperative to investigate the surface flashover performance of various commonly used solid insulating materials, in...
Plasma source of an inductively coupled impulse sputtering (ICIS) driven by high voltage burst pulse has been developed to generate high density plasma. In this study, the electrical characteristic of the ICIS driven by high voltage burst pulse was obtained using double probe measurements. The experimental apparatus consists of two electrodes immersed in an ICP driven by high voltage burst...
Electromagnetic rail launcher (EMRL) is one of the new propulsor based on impulse discharge with high current technique. In recent years, the research of EMRL has attracted the attention of domestic and foreign institutions, such as China, the United States Navy Laboratory, the French German Joint Laboratory, and has made great progress. In order to solve the fracture problem between bus-bar...
The Gamma Beam System – the future user facility – is being built in the framework of the Extreme Light Infrastructure–Nuclear Physics (ELI-NP) project in Bucharest/Magurele, Romania. This is an advanced source of gamma rays based on Compton back-scattering. By collision of a visible laser beam and a high brightness relativistic electron beam, an intense (~1011 γ/s), brilliant γ beam (<0.5%...
We performed computerized analysis of the L-3 Communications Pulserad flash X-ray system (Model 42710A) for explosion analysis in our laboratory. As a Site Acceptance Test, X-ray generation experiments have been carried out to collect data on dose measurements according to distance and azimuthal angle. Based on the X-ray measurement data, the computational analysis of diode and the...
This research details the high action pulse evaluation and corresponding modeling and simulation of a high voltage bipolar silicon carbide power device. A model of a high power bipolar device was developed in the Silvaco Atlas software to better understand the extreme electro-thermal stresses in the power device when subjected to an elevated-pulse current at a very unique time scale....
The beam dumping system of CERN's Large Hadron Collider (LHC) is equipped with fast solid state closing switches composed of a stack of ten series connected Fast High Current Thyristors (FHCT).
The triggering circuit of these switches consists of a 10:1 trigger transformer, with stray inductance of 5uH, powered by two redundant Power Trigger Modules (PTM) delivering 500 A peak gate current...
Observation shows that the electron orbit of the TLS (Taiwan light source) storage ring was greatly disturbed during the top-up injection process, both from BPM readings and profile monitor. The distortion duration exceeds the pulse lengths of both injection kickers and septum. It was speculated that one of the possible causes would be due to the eddy current effect induced by the leak field...
To continually increase the voltage and current capabilities of power semiconductor devices, whether pushing older materials such as Si to its’ intrinsic electrical limits or by employing newer substances like SiC or GaN, a thorough understanding of the entire device is required, from the basic physics of the material and its interactions with defects and passivation, up to the complete device...
High voltage long pulse klystron modulators typically use pulse transformers, where the length of the pulse dictates the size of the transformer. Recent advancements in power electronics applied to modulator technology have, in order to facilitate multi-millisecond long pulse generation, instead suggests use of high frequency transformers in a high frequency pulse modulation/demodulation...
The performance of hydrogen insulated, triggered 3-electrode spark gaps after long-term storage in argon, hydrogen and nitrogen has been investigated. 15 spark gaps were characterised and for each of the 3 different gases, 5 of those sparkgaps were stored for periods between 1 & 5 months. Those spark gaps with a storage period of 1 & 2 months were subjected to repeat tests. Before each testing...
Railguns allow to accelerate military payloads to large muzzle velocities and large muzzle energies. This enables the design of range enhanced artillery systems. These systems would allow to cover target distances of more than 100 km. As modern naval ships do have electrical power generation capabilities of the order of 10s of megawatts, it is reasonable to think of electrical, heavy naval...
AWE conducts hydrodynamic trials as part of its continual mission to maintain the UK nuclear deterrent. The trials utilise flash x-ray radiography as a key diagnostic for studying explosively driven experiments. Future trials will use a Self-Magnetic Pinch diode on the Merlin Inductive Voltage Adder as one of the radiographic sources.
This body of work presents predictions of the...
This paper describes an investigation into the performance of sparkgaps with hydrogen-nitrogen, argon-hydrogen mixtures and a hydrogen only gas fill. The spark gap was operated in both self-breaking and triggered modes of operation to quantify the voltage hold-off and trigger voltage requirements as a function of gas mixture and gas recovery time. An un-triggered spark gap was operated and the...
X-Ray flash radiography is a useful diagnostic for investigating the structural response of matter during hydrodynamic experiments. Intense pulsed X-ray sources are required to freeze the motion during these experiments and hence, produce sharp images. For this purpose, Linear Induction Accelerators (LIA) provide high flux X-rays pulses [1-2]. In order to optimize the electron beam transport,...
This paper describes the results of a study into the performance of a triggered three electrode, uv illuminated spark gap. A test cell containing the 3-electrode triggered spark gap and a separate two electrode spark gap (to provide the UV illumination) was developed initially. UV from the two electrode gap was produced by breaking the gap with an independent HV pulse generator, which allowed...
The pulsed power supply is one of the most important components in the electromagnetic launch system. The IPPS (Inductive Pulsed Power Supply) has attracted researchers’ attentions with its major advantages of high energy storage density (over capacitive pulsed power supply) and easy control (over rotating mechanical pulsed power supply). Since the circuit topology of the basic IPPS module...
Experiments have been carried out at the Naval Research Laboratory to measure the air response to an intense electron beam created using a 4 kA, 100 kV, 50 ns pulsed-power source. The electron beam is extracted through a pair of thin foils and injected directly into an 11-cm-long, 17.8-cm-diameter, gas-filled chamber. The properties of the plasma produced by the rapidly varying electron-beam...
Barrel side and pulsed power supply module are two crucial parts of an electromagnetic launcher, which affects the efficiency. The most important feature in the barrel side is the shape of the armature.
In this study, the shape of the armature is optimized by using independent variables to define the exact geometry of the armature. The main goal is to maximize the muzzle kinetic energy of the...
We are pursuing the development of 0.5-4 MV, 40-120 J/cm2 electron beams to benchmark and validate models of dynamic material response. Large-area sources at low impedance can be achieved using multiple parallel ring diodes, whose multiple current returns keep the local self-magnetic field below the threshold for pinching, thus alleviating the need for an external magnetic field. We report...
We demonstrate a high pressure, air-filled, spark gap switch with small gap geometries of 1.5 - 3.5 mm triggered using a laser induced plasma between the electrodes with laser energies as low as 500 uJ resulting in jitter from 350 ps to 2.2 ns when operated between 70% - 30% of self-break for voltages >100 kV. Switches of this design can be used for near-synchronous firing of 100’s to 1000’s...
Kicker magnets are specialised elements of the beam transfer system of particle accelerators, used to inject and extract beam from an accelerator. The deflection field produced by kicker magnets must rise/fall within the time period between the beam bunch trains; hence they typically produce rectangular field pulses with fast rise- and/or fall-times. In addition, the field must not...
Experimental study of system-generated electromagnetic pulse effect requires large area hard x-ray source with the average energy of photons less than 100 keV and few electrons. Compared with the single diode, the bremsstrahlung reflex triode can generate hard x-ray more efficiently to meet the demand of experiment. Reflex triode applies two face-to-face cathodes to reflex the electrons. The...
The plasma filled rod pinch diode (aka PFRP) offers a small radiographic spot size and a high brightness source. it operates in a very similar way to plasma opening switches and dense plasma focus devices - with a plasma prefill supplied by a number of simple coaxial plasma guns, being snowploughed along a thin rod anode before detaching at the end.
The aim of this study is to model the PFRP...
The UV laser triggering of high pulse power switches has been quite extensively studied over the past decades. This tool gives generally access to a reliable triggering with low jitter. New generations of lasers allow now to work with other wavelengths available at higher energy. How these two parameters interplay in the triggering mechanism? How could they be optimized to increase the...
The LHC beam extraction kicker system, composed of 15 fast kicker magnets per beam, is used to extract the particles in one turn from the collider and to dispose of them, after dilution, on an external absorber. Each of the 15 magnets is powered by a separate pulse generator, all of which are simultaneously triggered when a beam extraction from the machine is requested. Spontaneous firing of a...
It is proved by many researchers that the distributed-energy-store (DES) railgun can provide higher launch efficiency. This paper takes a 24MJ pulsed power system and an 8.5m long railgun as the simulation example, and analyzes the launch efficiencies and muzzle velocity accuracies from DES and breech-fed railgun. 24MJ pulsed power modules consisted of 234 pulsed forming units (PFUs) are...
Linear transformer driver (LTD) is an alternative pulsed power generation scheme to traditional pulse compression methods. Solid-state LTDs are being developed for industrial applications. They have advantages in system modularity and output flexibility. In addition, they are also featured by compactness and stress distribution.
Semiconductor power devices have been used as switches for the...
A large selection of materials have been investigated as electron beam producing repetitively pulsed cold cathodes. The cathodes were tested at 200 kV to 500 kV, 100 A to 110 kA, with cathode cross-sections ranging from 5 cm2 to 3000 cm2, and pulse widths from 50 ns to 300 ns. Cathode turn-on time and emission uniformity were measured, and cathode longevity was estimated...
The STRETCH meat grinder, put forward by IAT (Institute for Advanced Technology), is a typical inductive pulsed power supply (IPPS) unit for electromagnetic launch systems. When multiple STRETCH meat grinder modules supply one railgun load together, the currents flowing among these modules might cause them being coupled with each other. In order to promote the modularization of IPPS modules...
Pulse power systems applied in oil well stimulation device are required to work under circumstances of high temperature while the maximum working temperature is over 120℃. In traditional trigger devices, the capacitor discharges via the trigger surface when a high power thyristor closes the circuit, releasing enormous energy but the high power semiconductor devices and the drive circuits...
Performance of flash radiography system requires high spatial resolution. To produce point-like source of x-ray radiation electron beams focused on high-Z material are used. The target material is strongly heated by an electron beam with power deposition about of 1 kJ/mm^3. Dense plasma is formed that affects the beam via neutralization by fast ions and ionic instabilities. In this work we...
Recent studies have evaluated whether a ground-based electromagnetic (EM) acceleration system could provide a useful reduction in launch-to-orbit costs compared with the large chemical boosters currently used. Potential advantages of the EM launch approach include increased launch frequency, safety and reliability as well as cost reductions. There is a growing market for launch of small...
ASELSAN Inc. has been conducting experimental research on electromagnetic launchers since 2014. A 1 MJ Pulsed Power Supply (PPS) and 25 mm x 25 mm square bore 3 meters EMFY-1 Electromagnetic Launcher have been built at ASELSAN.
This paper represents results of the first experiments of EMFY-1 Electromagnetic Launcher with 1 MJ PPS and c-type aluminum armature. The pulse currents of the PPS...
Well diagnosed measurements of electrical breakdown between metal electrodes in vacuum have been made using a 1-MV, 50-ns pulse-generator-based test stand [1]. Results with bare, as-machined electrodes showed that cathode surface finish and material have little to no effect on the breakdown electric field. However, changing the AK gap did affect the breakdown field level, suggesting that the...
Pulsed streamer discharge plasma, a type of non-thermal plasma, is known to generate various chemically active species therefore widely applied to many fields such as water quality improvement and ozone generation. However, detailed physical properties of streamer discharge remain unclear. Thus, basic research on pulsed streamer discharge is necessary.
Some studies report the streamer...
In the last two decades, pulsed power technology has undergone a transformation from its nuclear roots to widespread application as specialized power conditioning in many diverse technical areas. Along the way, the field expanded to incorporate a wide variety of auxiliary competencies, fueled by its inherent multidisciplinary nature. These include the physics of ionized gas phenomena,...
A compact 210-kV, 10-kJ/s heavy-duty capacitor charger is described. One possible application is solids fragmentation. The charger has universal three-phase input. Pulse repetition rate (PRR) can be from single shot to 250 Hz, depending on the storage capacitance. Energy dosing (ED) topology [1] was chosen. It facilitates high wall-pug efficiency of typically 92% at switching frequency of up...
Recent progress in a variety of 3-D printing technologies that include various materials and much improved layer refinements have led to novel capabilities in rapid prototyping. NSWCDD has specifically incorporated this rapid prototyping ability for the design and testing of high voltage pulse power components that are relevant for high power radio frequency (HPRF) systems. Complex geometries...
Diversified Technologies Inc. (DTI) has installed a high-power solid-state opening switch upgrade package to replace the mercury ignitron crowbars in the Ion Cyclotron Resonance Heating (ICRH) Transmitters at MIT Plasma Fusion Science Center’s (PFSC) Alcator C Mod, a Tokamak-type fusion experimental device. The anode plate switch is rated for 30 kV, 200 A. The speed of the series opening...
For pulsed metallized film capacitors, the pulsed current would lead to the electrode fracture, which could further cause the decrease of capacitance, and the process could be accelerated when repetitive pulsed current passes. The pulsed current would further lead to the failure of metallized film capacitors, and shorten the lifetime of capacitors. Besides, the anatomical results of metallized...
In this paper, a circuit-PIC coupled model for 3-D electromagnetic (EM) PIC simulation is developed and introduced, which can be used in pulsed power system with magnetically insulated transmission line (MITL). The circuit-PIC coupled algorithm consists of an external circuit algorithm and a coupling algorithm. The external circuit algorithm based on BERTHA treats circuit elements as 1-D...
This work reports on theoretical studies for an isolated CLC resonant DC-DC converter to generate high voltage regulated including of a control system. The converter is based on a full bridge structure using Mosfets as switching devices. The output stage of the DC-DC converter is built using series-connected lower voltage modules. The proposed topology is based on DC-DC converter operating and...
Studies in recent years of pulsed power technology have led to applications in various fields such as medical, environmental, and agriculture. For practical applications, both energy efficiency and system simplicity are important. The nanosecond pulse discharge system developed by our research group generates pulsed power with a rise time of 5 ns and a peak voltage over 60 kV, resulting in low...
PROTO-SPHERA can be considered as the first tokamak with a simply connected configuration, namely without external components (as the central coil) inside the plasma volume. The tokamak-like shape is obtained by the self-organization of a plasma arc (pinch) in a cylindrical vacuum vessel, resulting in a minimal aspect ratio with a high confinement efficiency.
The first PROTO-SPHERA experiments...
The diffusion of a magnetic field through the walls of a hollow conductor is a problem that eludes analytical description with a few exceptions only. For instance, some solutions exist for cylindrical geometries in the limiting cases that the skin depth is much larger than or much smaller than the wall thickness. However, in pulsed applications, where the transient skin depth may be similar to...
A nanosecond pulse generator (NS-PG) which can generate high voltage pulses with duration of 5 ns and fast rise and fall times of 2 ns enables higher energy efficiencies of plasma processing. To enable development of a high-power generator for high processing capacity in the applications such as ozone generation and exhaust gas treatment, a low impedance NS-PG with higher output current was...
In order to generate high voltage high pulsed power, klystron modulators necessarily contain at least one capacitor bank charging structure supplying the energy to be released during the pulse. Conventional charging structures are based on AC/DC front-end units typically based on diode rectifiers combined with on/off power charging as a second stage, producing prohibitive levels of grid...
Pulsed power supplies (PPS) deliver high currents in a short period of time. Designing a pulse shaping inductor (PSI) requires major effort because of the electromagnetic forces exerted on the windings due to high pulse currents. A pulse shaping foil inductor is simulated with the help of finite element software COMSOL Multiphysics. Two different mechanical structures are designed in order to...
Abstract:Electromagnetic pulse formingis one of the most widely used pulse power techniques,thermal effect of electromagnetic pulse forming technology has been studied in this paper. The thermal effect is produced by the joule heat generated by the high current and the deformation of the sample in the process of electromagnetic pulse forming.The whole process is showed by simulation based on...
The dynamic behavior of High Voltage pulse transformers used in klystron amplifiers cannot be accurately represented with a standard low order lumped equivalent circuit because the distributed parasitic capacitances and leakage inductances are highly dependent of the detailed mechanical structure. A methodology based on generalized high order equivalent circuits identified from 2D and 3D FEA...
Recently, the widely application of nanosecond pulse discharge, such as flow control, enhance combustion, etc., has led to much more attention to the research of discharge under airflow.
Nanosecond pulse discharge under airflow is a typical multi-field coupling model, which contain a variety of time scales. Pulse discharge has a nanosecond time scale for a single pulse, as well as the PRF of...
Power electronic loads are being connected to the distributed power plants through power electronic converters and these power electronic converters and loads are the source of harmonics and reactive power which affects the performance of the power system network. Switching compensators called Active filters or active power line conditioners brings an effective alternative to the conventional...
The Air Force Research Laboratory has been studying ceramic dielectric materials for high voltage pulsed power capacitor applications. As part of this effort, we have been developing an electric breakdown model for ceramic dielectrics using AFRL’s massively parallel 3-dimensional electromagnetic particle-in-cell code, ICEPIC. First a method to generate randomly shaped polyhedral utilizing...
Triggering of high voltage Marx generators generally involves multiple stages, with the lower voltage signals associated with control systems being amplified to higher voltages to ensure operation with: high reliability, low jitter, and low probability of pre-fire. At the Sandia National Laboratories Z Machine, the trigger chain for the thirty-six Main Marxes includes a primary 100 kV laser...
Increasing ship-board power demand coupled with environmental sustainability initiatives has created interest in pursuing all-electric ships (AES) for both commercial and military applications. AES can be equipped with power electronic components, loads, machines, and cables. Many electric generator topologies can be used for AES. Permanent-magnetic synchronous generator (PMSG) is the most...
Abstract
Plastic case capacitors have been developed that offer compact, economical, low inductance solutions for a variety of high voltage pulse power applications. Both extended foil and tapped foil configurations, combined with rail terminals, have been designed for fast discharge (≤ 1μs pulse width) low inductance and low capacitance units. For the highest rep rates and RMS currents,...
Diversified Technologies, Inc. (DTI) recently completed and delivered a 400 kVDC, 400 mA power supply for a commercial client. The 160 kW average power supply is comprised of 16 25 kV modules arranged in a vertical, air-insulated stack. Electrically, the system is a Cockcroft-Walton cascade multiplier fed by a standard DTI high power, high voltage inverter.
Discharge in liquid has been researched for about half century since the 1960s, but the theories of discharge in liquid are of great variety. We can simply classify those researches into direct current discharge in liquid, radio frequency (RF) discharge and microwave discharge in liquid and pulse discharge in liquid according to the frequency of the power source. We can also classify those...
Pulsed Power Technologies involved some electrical loads which required a fast rising (ns) input high current pulses. Pulse conditioning of slow rising (µs) high current pulse is very essential in this regard. A compact and an efficient solution based on metal fuses is modeled and experimentally verified the modal validity. Metal fuses referred as Electrically Exploding Fuses (EEF) consist of...
Random garbage content
