Degradation and training in superconducting magnet: revisited

Superconducting magnets will usually settle down to a fairly constant performance, after many training quenches, at currents which may be appreciably higher than the initial quench currents, but still less than Ic and fluctuating in a random fashion. So far, there was no theory to understand the phenomenon, though people talked about movement of wires, cracking of epoxy as the plausible explanations. Based on the “Worst Defect Cluster” model suggested by Duxbury and Leath, a theory has been proposed for the first time to understand the statistical nature of the phenomenon.