Influence of locally varying Jc distribution on AC transport losses for superconductor wires and tapes with various cross sections

The influence of locally varying J(c) value on AC transport losses in self-fields is investigated on superconductor wires and tapes with various cross sections through numerical calculations. For round wires, the loss values depend on the J(c) variation along a radial direction in their cross sections. The distribution that J(c) increases in going from the center to the edge along a radial direction lowers the loss value, below the theoretical prediction for an elliptic superconductor without any J(c) variation. For tapes, the loss values are mainly influenced by the J(c) variation along a width direction. The rectangular tapes with high aspect ratio and also with nearly uniform J(c) value behave as a thin strip superconductor. The distribution that J(c) decreases in going from the center to the edge along a width direction raises the loss value, and the loss value approaches the theoretical prediction for an elliptic superconductor as the J(c) variation becomes significant. (C) 2002 Elsevier Science B.V. All rights reserved.