Flux Instabilities in High Field Superconducting Wires

Publisher Website
Google Scholar
Abstract
The magnetic flux instability is investigated in Nb-25% Zr wires, 0.25 mm in diameter, and the low field instability is found to be an intrinsic phenomenon of high field superconducting wires. The flux Jump is induced artificially by an application of the heat pulse and the magnetic field pulse. The stability is represented quantitatively by a minimum power of the pulse P c at which the superconductor quenches into a normal state. The critical power P c reduces discontinuously above a certain current, the threshold current I t . Threshold current I t and P c depend on the history of the field-current application. The stability at the current above I t increases with increasing ambient magnetic field and with decreasing critical current. Partial flux jump is induced above a certain current I f below I t . The detailed structure of the distribution of the magnetic induction in the sample plays an important rote in the stability.