Strong Pinning and Plastic Deformations of the Vortex Lattice

We investigate numerically the dynamically generated plastic deformations of a 3D vortex lattice driven through a disorder potential with isolated, strong pinning centers (pointlike or extended along the field direction). We find that the vortex lattice exhibits a very peculiar dynamical behavior in the plastic flow regime, in particular, topological excitations consisting of three or four entangled vortices are formed. We determine the critical current density jc and the activation energy for depinning Uc in the presence of a finite density of strong pinning centers. copyright 1996 The American Physical Society