Experimental and Simulation Research on High-Temperature Superconducting Persistent-Current Switch Operated in Solid-Nitrogen Environment

High-temperature superconducting (HTS) persistent-current switch (PCS) is an essential device for on-board HTS magnets achieving the closed-loop operation mode. This work proposed a type of the heater-triggered HTS-PCS operated in SN<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> environment. The thermal structure of the HTS-PCS is introduced in detailed. The thermal characteristics including switch OFF time, switch ON time, and temperature rise of the HTS-PCS operated in SN<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> environment are studied via experimental tests and simulation analysis. The used simulation model is a thermal simulation model constructed based on the finite element method. The effect of the solid-solid and solid-liquid phase transitions of nitrogen has been taken into account. The effectiveness of the simulation model is verified by the experimental tests. The research results show that the HTS-PCS with ∼0.53 Ω off-resistance can be switched OFF within 5 min and switched ON within 25 min in SN<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> environment, and the outermost layer temperature does not exceed 65 K. This study provides useful information for the design of the HTS-PCS operated in SN<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> environment.