What is the creep exponent:

The key parameter for the flux creep simulations is the ratio of the characteristic pinning energy U_c to kT. For logariphimic dependence U = U_c ln( j / j_c ) this ratio is equal to the exponent n in the current-voltage curve: E(j) ~ jⁿ and often called the creep exponent. The critical state model (flux creep is absent) corresponds to infinitely large U_c/kT. As the ratio  U_c/kT   decreases, the flux creep becomes stronger. Here we present results of simulations with two different creep exponents, U_c/kT = 3 and 33.

Flux creep movies:

Parameters:

The applied field is swept with a constant rate |dH/dt| = 0.001 H_max v_c / 2w; the pinning barrier U = U_c ln( j / j_c ). The maximal value of the applied field H_max is chosen so that at H = H_max the flux front approximately reaches the superconductor center.
H, j, E, and M are normalized to H_c, j_c, E_c= v_cB_c, and M_c, where M_c is the magnetization in case of uniform current density equal to j_c; H_c = w j_c for a slab of width w or H_c = d j_c/ pi, for a strip with thickness d.