Initiation of flux jump in SC composite by heat pulse

Abstract

Nonisothermal diffusion of magnetic flux after a heat pulse shot on the surface of SC (superconductor) composite has been studied numerically taking into account the smoothed transition characteristic of the SC. It is shown that for an SC composite with poor stabilization, the current and heat redistribution change significantly the estimations of stability based on steady-state functions of heat generation and heat transfer. The critical pulsed energy strongly depends on the initial current distribution over the conductor cross section, and the energy may be much less for a conductor with growing current than for a conductor with the same current in steady state. It has been found that undercritical heat pulses only slightly affect current density profile, but stability increases as time delay increases between the current input halt and the pulse shot. It has also been found that for a SC composite with poor stabilization, the transverse thermal conductivity is more important than the electrical resistivity of the matrix from the stability standpoint. >