Influence of coupling current among superconducting strands on stability of cable-in-conduit conductor

Stability margin of the Cable-in-Conduit Conductor used under the pulse field is greatly influenced by inter-strand coupling losses and current unbalance with coupling current among strands. The large transverse resistance trades sufficient current transfer among strands for low AC losses. The large stability margin is brought by sufficient current transfer, low AC losses and uniform current distribution. Then we should decide the reasonable value of transverse resistance corresponding to the pulse condition. In this paper, the stability is estimated by the simplified distributed constant circuits simulating unbalanced current, that is transient coupling current, and transfer current among strands. In the non-insulated strands, the inductive voltage occurred during charging in a twisted area of half pitch must be enough lower than normal voltage of local quench at the limiting current. This paper also shows that the short twisted pitch and long cables about 1000 m give not only low AC losses but also uniform current distribution during charging for insulated strands