DISTURBANCE CHARACTERISTICS AND STABILITY OF HIGH-CURRENT DENSITY SUPERCONDUCTING WIRES

The characteristics of a possible disturbance should be taken into consideration when we design high-current density superconducting wires or magnets. The minimum quench energy (MQE) is used as measure of stability. The frictional motion of the wire is the disturbance which is most responsible for the quench. The magnitude of MQE is influenced by its time duration, but the dependence of MQE on the copper to superconductor (Cu/SC) ratio is not so influenced by its time duration of reasonable value. The spatial size of the possible disturbance is difficult to predict, but the numerical results show that, when the spatial size of the disturbance is much smaller than the MPZ, its influence on MQE and the optimum Cu/SC ratio is not significant. When we design a wire with small overall current density, a larger Cu/SC ratio is favorable to attain larger MQE. When we design a wire with high overall current density, a smaller Cu/SC ratio gives larger MQE. However, especially, in an intermediate region of overall current density, the influence of Cu/SC ratio on MQE is small.