A novel heater-triggered HTS semi-persistent current switch with high switching-off resistance

Abstract

A semi-persistent current switch (semi-PCS) with a simple fabrication process, high switching-off resistance, and minimal power dissipation during operation is required to realize the semi-persistent mode in a high-temperature superconducting (HTS) magnet. In this study, a semi-PCS with high switching-off resistance was developed by optimizing the HTS tape structure in a heater-triggered semi-PCS. This optimization was achieved by selectively removing a portion of the conductive and superconducting layers on the surface and edges of the HTS tapes. The microstructure of the treated HTS tape was then analyzed. The resistance of the semi-PCS in a non-superconducting state was measured, and it was connected to an insulated coil for performance testing. To further evaluate its impact, an equivalent electrical circuit model was developed and used to predict the effect of the semi-PCS when applied to a larger superconducting coil. Furthermore, the study explored the impact of the excitation rates on the power dissipation and heat generation of the semi-PCS.