Dynamic vortex pinning in a type II superconductor

Abstract

The current-voltage characteristic of an irreversible type II superconductor depends on the interaction of moving flux vortices with flux pinning defects. Experimental characteristics display curvature and fine structure whose origin is still uncertain. In this paper a phenomenological framework is established for calculating the response of a moving vortex under the action of local forces. It is shown that the vortex lattice restoring forces can be treated using a self-consistent mean-field approximation. Using this approximation the distribution of vortex displacements, the velocity distribution and the mean voltage are calculated for a simple one-dimensional model pinning system.