Charging Test of Through-Wall Linear-Motor Type Flux Pump at Temperatures Ranging from 30 K to 77 K

The linear motor-type flux pump enables contactless excitation of high-temperature superconducting (HTS) magnets, thereby eliminating the need for current leads in the cryogenic system of superconducting magnets. However, if the linear motor-type flux pump is directly installed within the cryogenic Dewar, the heat generated by the flux pump itself would impose a significant thermal load on the cryogenic system. In this work, we propose a novel method to achieve through-wall excitation of superconducting magnets by utilizing a linear motor-type flux pump. The main body of flux pump is installed outside the Dewar, and a flange with magnetic-conducting components is used to transmit the magnetic field to the interior of the Dewar, thereby achieving through-wall excitation of the superconducting magnets. Based on the through-wall excitation platform developed in our laboratory, this work presents an optimized through-wall excitation flux pump, and reports charging performance tests on superconducting stators and superconducting magnet at temperatures ranging from 30 K to 77 K. The test results will be used to study the macroscopic magnetic coupling effect at low temperatures and boost the applications of through-wall excitation flux pumps in HTS magnets in various fields such as MRI/NMR, maglev trains, and accelerator magnets.