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 ju nction arrays and superconducting films driven by a current. We find a dyna mic 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 sca le xi(v) in the direction of motion, which diverges when approaching I-p Ab ove 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 asympt otically a liquid for large length scales. [S0031-9007(98)08089-2].