Losses in superconducting multifilament composites under alternating changing fields

A brief review of the losses in superconducting composites in a changing external field is presented. The losses are expressed for a single triangular shaped pulse and for a field varying exponentially with time. The case of an oscillating sinusoidal field is considered. In particular, in a rapidly varying field, several layers of filaments can be saturated by returning currents. Complete expressions of the losses are provided together with simplified expressions. A comparison between several kinds of conductors shows that in some cases the losses are reduced by increasing the twist pitch of the conductor.