Dendritic flux avalanches in superconducting films of different thickness

Abstract

At low temperatures the critical state in superconducting films can be unstable with respect to thermomagnetic dendritic avalanches. By numerical simulations of disk-shaped superconductors, we consider how the dynamics and morphology of the avalanches depend on the disk thickness. We find that as the disks get thicker, the jumps in magnetic moment caused by the avalanches get larger and the threshold magnetic field for the appearance of the first avalanche increases. At the same time, the branches are straighter and the number of branches decreases. Comparison with theory suggests that strong spatial disorder to some extent cancels the stabilizing effects of the substrate kept at constant temperature.