A Large-Bore HTS Magnet for Generating AC Magnetic Field

High-temperature superconducting (HTS) metal-insulation (MI) magnet has been proven to be suitable for generating high magnetic fields due to its large current-carrying capacity, excellent thermal stability, and quench self-protection ability. However, there are very few reports on the use of HTS MI magnets for generating AC magnetic fields. Recently, Institute of Electrical Engineering, Chinese Academy of Sciences has designed and fabricated a large-bore HTS magnet generating extremely low-frequency magnetic field, which is used for biological nerve regulation experiments. The magnet consists of 90 HTS MI double-pancake (DP) coils with an inner diameter of 453 mm and works at 20 K under conduction-cooling conditions. In the test, the magnet can produce a central magnetic field of above 0.8 T under DC conditions, while the AC magnetic field is affected by operating current, frequency, and contact resistance under AC conditions. This article introduces the design, fabrication, and test of the magnet, and discusses the characteristics of the AC magnetic field generated by HTS MI magnet.