Analysis and measurement of AC transport current loss in BSCCO tape in external magnetic field

A numerical model to calculate current distribution and AC loss in a high temperature superconducting tape carrying AC transport current exposed to an external magnetic field was developed. The model considers the electric field and current density relation and the shape of wire. The authors measured the AC transport current losses in a conventional Bi2223/Ag multifilamentary tape in a DC external magnetic field and the results were compared with the numerically calculated AC losses. The measured AC transport current losses increase as the DC external field increases. It is also shown that the measured losses per cycle decrease with increasing frequency. These characteristics cannot be explained by the critical state model. The numerical losses by their model reasonably agree with the measured data. The transport loss characteristics under the DC field and their dependence on the frequency are explained by the numerically calculated current distribution in the wire.