Load line analysis of Bi-2223 tape-stacked-cable for self field effects

In general, the critical current of a Bi-2223 tape-stacked-cable is much less than the total summation of critical currents of each tape, which is mainly due to the self magnetic fields of the cable itself. Therefore, to predict the critical current of a Bi-2223 tape-stacked-cable, we need to analyze the self field effects of the stacked cable as well as the critical current density data (J/sub c/) of one tape. To make it more complex, the critical current degradation of a Bi-2223 tape is anisotropic; the critical current is lower in the normal magnetic field (to the tape surface) than in the parallel field. In this paper, a novel approach to predict the critical current of a Bi-2223 tape-stacked-cable from a J/sub c/-B curve of one tape is presented. The approach basically includes the load line analysis of the stacked tapes, and its usefulness is confirmed by the experimental data.