Numerical Study on the Two-Dimensional Vortex System with Random Pinning

We study numerically the dynamic behavior of the two-dimensional vortex lattice, moving in a random pinning potential under the action of an external driving force. Different densities of randomly distributed pointlike pinning centers and different vortex-vortex interacting strength are considered. Then the elastic and plastic regimes are found to be dependent on the relation between the vortex-vortex and the vortex-pin interacting potentials. The critical driving force increases with increasing density of pinning centers and with decreasing of the vortex-vortex interacting strength. The simulated results are consistent with the recent experiments, and some of our results fall outside the region of validity of collective pinning theory.