Mechanical and electromagnetic characteristics of MgB2 wires & Cable-in-Conduit Conductors for fusion magnet application
Peng Gao, Jiahao Wan, Yishan Chen, Hongjun Ma, Weijun Wang, Xintao Zhang, Chao Dai, Tianli Dai, Min Yu, Arend Nijhuis, M. Rindfleisch, Mike Tomsic, Huan Jin, Huajun Liu, Fang Liu, Jinggang Qin, Chao Zhou
Abstract
A study on a 4-stage sub-size MgB 2 Cable-in-Conduit Conductor (CICC), tested at the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), revealed a 20% degradation in critical current at 4.2 K compared to single-strand data. To address this issue, the mechanical properties of MgB 2 wires from Hyper Tech and WST were investigated, and two sub-size CICCs were manufactured using a “close-to-1-ratio” Twente design with smaller diameter wires. These cables demonstrated no significant degradation in critical current after cabling and compaction, nor after electromagnetic load cycling. The results indicate that the close-to-1-ratio cable design is optimal for brittle superconducting materials such as MgB 2 , Nb 3 Sn, and BSCCO, as it minimizes mechanical stress and preserves superconducting properties. This design shows significant potential for the application of MgB 2 in next-generation fusion reactors, particularly in Poloidal Field (PF) coils, Correction Coils (CC), and feeders.