Screening current in ultra-high-field non-insulated superconducting magnets  

作　　者：ZHOU BenZhe WANG Lei CHEN Yong WANG QiuLiang WANG KangShuai ZHANG ZiLi LIU JianHua 

机构地区：[1]University of Chinese Academy of Sciences,Beijing 100049,China [2]Institute of Electrical Engineering,Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Science China(Technological Sciences)》2024年第7期2255-2273,共19页中国科学（技术科学英文版）

基　　金：supported by the National Key Research and Development Program of China (Grant No. 2022YFA1602800);the National Natural Science Foundation of China (Grant Nos. 52325701, 52293421, 52293422, and 52293423);the Synergetic Extreme Condition User Facility (SECUF) Project。

摘　　要：Screening current is recognized as one of the critical elements limiting the progression of superconducting magnets toward achieving higher magnetic fields. Currently, most non-insulated(NI) superconducting magnets consider the magnet as insulated when addressing the issue of screening current. However, the bypass current in the NI magnet can modify the actual history of magnetization, so the screening current in NI magnet will be different from that in the insulated magnet. This paper presents a novel method based on the homogenized T-A formulation(T is the current vector potential, and A is the magnetic vector potential), which enables real-time simulation of both the bypass current behavior and the implications of screening current in NI superconducting magnets, even when these magnets contain tens of thousands of turns. We have developed a 32 T NI hybrid superconducting magnet and validated the effectiveness of this method through experiments. Employing this efficacious method,we conducted a comprehensive calculation of screening current in NI magnets, comparing them with insulated magnets in terms of screening current-induced stress(SCIS), screening current-induced field(SCIF), and losses. The results indicate that in the NI insert coils, the sequential excitation of background coils and insert coils induces a reverse screening current, resulting in slightly lower SCIF and SCIS compared to those in the insulated magnets. The method and results can contribute to the enhancement of magnet design and provide valuable insights for the development of ultra-high fields(UHF) NI magnets.

关 键 词：ultra-high-field superconducting magnet screening current REBCO coil NI coil stress loss 

分 类 号：TM26[一般工业技术—材料科学与工程]