Numerical study of the nonlinear a.c. response of flux motion in type II superconductors

Abstract

The nonlinear a.c. response of the flux motion in type II superconductors is studied using a single flux motion model. We have performed a numerical simulation and evaluated the a.c. response against frequency. Three cases of applied current are considered a single-frequency ax. current, an a.c. current of two frequencies and a d.c. plus an a s . current. We find that, when the Lorentz driving force is greater than the pinning force, there exists a crossover frequency below which a strong nonlinear a.c:response is exhibited. We also find that the value of this crossover frequency has a linear relation with the ratio of the Lorentz and the pinning forces.

Electromagnetic and thermomagnetic properties of high- superconductor in its mixed state: the single-vortex-motion model

“…In this respect, it is still of importance to study the ac responses numerically. We note that in [82,83,84], employing a model of singlevortex motion, the authors have developed a numerical algorithm to calculate the ac resistivity in the mixed state with regular or random pinning. Despite the simplicity of the model, their numerical results seem to be in qualitative agreement with experimental results.…”