A dynamic model for flux jumps in typeminus;II superconductors

摘要

The behavior of flux jumps in hard typeminus;II superconductors can in principle be described by solutions of coupled thermal and magnetic diffusion equations. A simple magnetic diffusion equation for hard typeminus;II superconductors based on the fluxminus;flow concept is proposed and numerical solutions are presented for physical parameters corresponding to a sample of NbTi. Although simplifying assumptions, such as adiabatic conditions and theJcindependence of magnetic field, are made, both the threshold field of stability and the rate of flux collapse are found to agree at least qualitatively with epxerimental values obtained in a NbTi rod. Calculated sequences of magnetic field, temperature, and power density profiles occurring during flux jumps are presented.