Switching reaction of Nb₃Sn persistent current switch with a high current capacity

We designed a persistent current switch (PCS) consisting of Nb₃Sn superconducting wire for superconducting magneto-hydrodynamic propulsion ship. Nb₃Sn has T_c higher than NbTi, which is commonly used for the conventional PCS, and thus Nb₃Sn is expected to show a higher stability against disturbance. We performed numerical simulations for the heat transfer in a 3-kA-class Nb₃Sn PCS by using a finite element method. We then constructed a 3 kA-6 Ω Nb₃Sn PCS and measured its switching performance. The results obtained in 3-kA PCS are utilized for the simulation of 10-kA-class switching performance including numerical simulations for the heat transfer. The results of switching performance will be presented based on the computer simulation for temperature distribution during the heating and cooling cycles. We also present the estimated time for the transition from the superconducting to normal state (off-state) and vice versa (on-state).