Quench Behavior of 2G HTS Coils with Polyimide Film and MIT Material under Over Pulse-Current

This paper presents the quench behavior of second-generation (2G) high-temperature superconducting (HTS) coil insulated with a Kapton polyimide film or metal-insulator transition (MIT) materials, which could enhance the thermal stability and magnetic field-control performance of a 2G HTS magnet. For the quench test, overcurrent experiments using pulse-current shooting were conducted to investigate the thermal quench behavior and thermal stabilities of two HTS coils co-wound by polyimide or MIT materials against a large overcurrent pulse. The experimental results of the two insulation materials were compared to verify the superior thermal performance of the MIT material as the turn-to-turn insulation. Further, the applicability of the MIT material on a 2G HTS magnet system was discussed according to the experimental results.