Conveners
Fri-Mo-Or27 - No-Insulation and Insulated REBCO Magnet Technology
- So Noguchi (Hokkaido University)
- Hubertus Weijers (NHMFL/FSU)
It was a milestone to generate a record-high DC field of 45.5 T by use of a 14.4 T no-insulation (NI) REBCO insert, named Little Big Coil (LBC), operated in a 31.1 T resistive background magnet by the National High Magnetic Field Laboratory. The engineering current density of the NI REBCO insert was ~1200 A/mm2 at 45.5 T, nearly 6 times larger than that of the conventional insulated HTS coils,...
We aim to develop a persistent-mode 1.3 GHz (30.5 T) NMR magnet with a REBCO layer-wound (LW) insert, a Bi-2223 LW midsert and LTS LW outsert. Protection of the REBCO insert is of great importance and we have employed intra-layer no-insulation (LNI) method in a magnet design [1],[2]. In the present work, we developed a model magnet similar to the 1.3 GHz NMR magnet, i.e. REBCO/Bi-2223/LTS...
In a REBCO no-insulation (NI) magnet coil, the turn-to-turn contact resistance (Rc) determines the coil’s quench self-protection ability, charging delay time and the energy loss during field ramp. Therefore it is critical to control Rc to suitable values. In our previous investigation, we measured Rc at 77 K and 4.2 K under various contact pressures and pressure cycles, and studied the effect...
Because nowadays high temperature superconductors (HTS) can carry very strong currents under a high strength magnetic induction at a low temperature, the generation of continuous magnetic fields in the 25 to 50 T range, unattainable with conventional superconductors, is becoming reality.
However, HTS magnets must be effectively protected against transition to the normal state (quench),...
High temperature superconductor (HTS) no-insulation (NI) coil is widely applied on high field magnets. In a multiple coil system, the quench behaviour of one coil is considerably affected by other coils through electromagnetic coupling. Meanwhile, quench on one coil can induce a current and fields changing on other coils, which may leads to eddy loss and mechanical degradation on these coils....
The development of ambitious REBCO HTS coils (Rare-EarthBiCaCuO High Temperature Superconductor) is faced by two commonly acknowledged issues: Protection against thermal runaway induced by local dissipative zones, and dynamic field homogeneity. These two problems stem from two specificities of REBCO Coated Conductors: significant spatial inhomogeneity of critical current density and large...
The 32 T all-superconducting magnet of the National High Magnetic Field Laboratory was successfully tested in December 2017 and it is expected to be available for users in 2019. This all-superconducting magnet, comprised of two HTS inner coils and five outer LTS coils, is the first superconducting magnet above 30 T and some 8 T beyond the current strongest superconducting magnet in use as a...
The screening current in REBCO coils has been proved to have an important impact on the field quality, which is critical for applications with high field homogeneity requirement, such as MRI and NMR. As demonstrated in ‘Little Big Coil’ experiments by NHMFL, the screening current in REBCO coils may also have a huge influence on its strain distribution, especially for high-field operations. A...
