Simulations of current: Driven three-dimensional Josephson junction arrays

We present Langevin simulations of anisotropic three-dimensional Josephson arrays driven by an external current. We study the superconducting phase transition at zero magnetic field, by analyzing both the helicity modulus and the voltage. We find that there is a well defined phase transition at any finite current smaller than the Josephson critical current. The critical temperature T-c(I) obtained decreases linearly with current I. We also find that the onset of voltage occurs at temperatures smaller than T-c(I). We discuss the consequences of this result for the interpretation of recent experiments in the flux transformer configuration.