Current-voltage characteristics in a two-dimensional model for flux flow in type-II superconductors

It is argued that flux motion near threshold in a macroscopic, two-dimensional lattice with a random potential, under the influence of an external driving force, always involves plastic flow of moving portions of the lattice past regions that are pinned. Convincing evidence for this picture is obtained from a comparison of experimental measurements to computer simulations of the non-linear curent-voltage characteristics of finite systems.