Plasticity in Current-Driven Vortex Lattices

We present a theoretical analysis of recent experiments on current-driven vortex dynamics in the Corbino disk geometry. This geometry introduces controlled spatial gradients in the driving force and allows the study of the onset of plasticity and tearing in clean vortex lattices. We describe plastic slip in terms of the stress-driven unbinding of dislocation pairs, which in turn contribute to the relaxation of the shear, yielding a nonlinear response. The steady state density of free dislocations induced by the applied stress is calculated as a function of the applied current and temperature. A criterion for the onset of plasticity at a radial location $r$ in the disk yields a temperature-dependent critical current that is in qualitative agreement with experiments.