Coupling-current loss in a multifilamentary superconducting wire with a normal-metal core

Coupling-current losses in a multifilamentary superconducting wire with a normal metal core were calculated for the case of transverse magnetic fields. The results showed that the dependence of the coupling-current loss of such a wire on the rate of field variation is markedly different from that of a wire without the core, the former being characterized by two time constants while the latter by one. The theoretical result was confirmed experimentally. It was pointed out that in the case when a wire with Cu/CuNi matrices is to be used in a rapidly changing magnet field, Cu for a stabilization should be arranged at the centre of the wire rather than at the surface of the wire in order to reduce the loss.