Dynamic transition in vortex flow in strongly disordered Josephson junction arrays and superconducting thin films

We study the dynamics of vortices in strongly disordered d = 2 Josephson junction arrays and superconducting films driven by a current. We find a dynamic phase transition in vortex how at a current I-p > I-c. Below I-p there is plastic flow characterized by an average-velocity correlation length scale xi(v) in the direction of motion, which diverges when approaching I-p Above I-p we find a moving vortex phase with homogeneous flow and short range smectic order. A finite-size analysis shows that this phase becomes asymptotically a liquid for large length scales. [S0031-9007(98)08089-2].