DIFFUSION-MODEL FOR THE COMPUTATION OF CURRENT-DENSITY DISTRIBUTIONS IN COMPOSITE SUPERCONDUCTORS

We propose a magnetic diffusion model for the computation of current d ensity distributions in composite superconductors. The two-dimensional model is based on Maxwell's equations and a non-linear constitutive r elation between the current density and the electric field. The result ing diffusion equation is solved using the finite element method. We p resent numerical results on the time evolution of the current density distribution and the surface electric field in monofilamentary superco nducting tapes excited by slow current ramps. The results demonstrate that the diffusion model appropriately describes the critical state, t he electric field due to the self-field effect, and current sharing in composite superconductors. (C) 1996 Elsevier Science Limited