Comparison of two methods for analysis of vortex motion: Flux creep versusNonlinear current-voltage curve approach

We compare two commonly accepted approaches for simulations of thermally-ac tivated vortex motion in superconductors. The dux creep approach is based o n the expression E = nuB for the electric field vis the local flux density and the velocity of the thermally-activated flux motion. The other approach employs a phenomenological nonlinear current-voltage curve, E(j). Our nume rical simulations show that the two approaches give similar but clearly dif ferent results, the difference being most pronounced in the areas of low B. We find that the flux creep approach provides a better description of the experimental current distributions in a YBaCuO current-carrying strip deter mined by magneto-optical imaging.