Measurement of current distribution in multi-strand superconducting cablesfor AC use in both steady and transient states

We experimentally investigate current distribution in steady and transient states in multi-strand superconducting cables composed of strands without i nsulation for AC use. The current distributions are indirectly measured fro m the results of the self-field distribution observed by a group of pickup coils located around the cable, Several patterns of localized current distr ibution induced by heaters are measured using two different types of pickup coils. The current values are calculated from the measured voltage values of pickup coils. The obtained results from these calculations show that the transient changes of the current distributions can be successfully measure d and explained. Further, we observe that the localized current distributio n tends to be uniform with increasing frequency. On the basis of the obtain ed results characteristics of current distributions in the AC super-conduct ing cable are discussed.