Mechanical strain triggering flux jumps of multi-filamentary Nb_(3)Sn wires  

作　　者：Qing-Yu Wang Cun Xue You-He Zhou 

机构地区：[1]School of Aeronautics,Northwestern Polytechnical University,Xi’an 710072,China [2]School of Mechanics,Civil Engineering and Architecture,Northwestern Polytechnical University,Xi’an 710072,China [3]Key Laboratory of Mechanics on Disaster and Environment in Western China Attached to the Ministry of Education of China and Department of Mechanics and Engineering Sciences,Lanzhou University,Lanzhou 730000,China

出　　处：《Superconductivity》2022年第4期14-21,共8页超导（英文）

基　　金：support from the National Natural Science Foundation of China(Grant Nos.11972298).

摘　　要：The composite multi‐filamentary Nb_(3)Sn wire with a high critical current density is a preferred option for fabricating the superconducting magnet beyond the limit of NbTi wire(9–16 T).However,one crucial issue stems from the fact that electromagnetic force in superconducting coils is very strong,and the critical physical properties of Nb_(3)Sn,such as Jc,are more sensitive to mechanical strain than those of other possible low‐temperature superconductors.We theoretically investigated the impact of mechanical strain on the thermomagnetic instabilities such as the flux jump(FJ)and quenching of Nb_(3)Sn wire exposed to a static magnetic field and transport current.The good agreements with H formulation or H‐φformulation implemented on COMSOL software confirm the validity of our numerical simulations using home‐made codes.It is discovered that mechanical strain can trigger flux jumps even in a static magnetic field.Furthermore,the threshold value of mechanical strain to trigger the first flux jump is a monotonic function of the static magnetic field in the case of high transport currents,while it is a non‐monotonic function in the case of low transport currents.It is attributed to the fact that flux can be released by the mechanical strain,causing smooth flux penetration before triggering the flux jump.We also present the stable/unstable regions by applying mechanical strain by varying transport current,magnetic field,and working temperature,which helps in avoiding thermomagnetic instabilities while designing the superconducting magnet.

关 键 词：Nb_(3)Sn wires Thermomagnetic instability Flux jump Mechanical strain 

分 类 号：O462[理学—电子物理学]