CRITICAL-DYNAMICS AND PLASTIC-FLOW IN DISORDERED JOSEPHSON-JUNCTION ARRAYS

We present numerical simulations of Josephson junction arrays with positional disorder. We study their IV characteristics and vortex dynamics as a function of disorder. We find that above the critical current i(c) there is a plastic flow of vortices and antivortices through channels, characterized by strong fluctuations of the total vorticity. For large currents there is a crossover to homogeneous flow without vortex fluctuations. We also study the dynamical critical behavior close to i(c) in the gauge glass model, calculating critical exponents for the voltage onset and voltage fluctuations.