Stability analysis of multi-strand superconducting cables

When a normal zone is produced in one or a few strands in a multi-strand superconducting cable by a localized disturbance, the current in the normal-transited strand transfers to the others via contact resistance between strands. Heat generated in the normal zone also diffuses to the other strands. The stability of the multi-strand superconducting cable against local disturbances is much influenced by these current transfer and thermal diffusion. The influence of the copper resistivity on current transfer and stability is studied. When we plot the MQE on "contact resistivity"-"contact thermal conductivity"-plane, there are a stable region with large MQE and an unstable region with small MQE. The small contact resistance and small contact thermal conductivity between strands are preferable from the view point of stability. If the contact thermal conductivity is small, the transition from the stable region to the unstable region is drastic.<>