KINEMATIC VORTICES AND PHASE-SLIP LINES IN THE DYNAMICS OF THE RESISTIVE STATE OF NARROW SUPERCONDUCTIVE THIN-FILM CHANNELS

The resistive state of a superconducting thin film channel (bridge) of intermediate width W(xi much less than W much less than lambda(eff), xi is the coherence length and lambda(eff) is the effective magnetic penetration depth) - this case is relevant to the nanoscale high-T(c) superconductor thin film bridges - is studied by simulations of two-dimensional time-dependent Ginzburg-Landau equations. It is found that in the uniform narrow channel at high dimensionless conductivity SIGMA the dynamical behavior is due to appearance of the phase slip lines, but at lower SIGMA vortices appear in the resistive state. In inhomogeneous channels vortices appear at any SIGMA. We call these vortices kinematic vortices because, unlike the Abrikosov vortices, they can not be treated as quasiparticles. They move with any velocity depending on the current distribution over the bridge (the bridge inhomogeneity). The more uniform the current distribution, the higher the vortex velocity. A kinematic vortex with infinite velocity is a phase slip line.