Empirical study of a current-distribution control type advanced superconducting conductor

在不能控制电流分布和导线间接触电阻的超导导体中，如在设计时没有考虑到的长时间常数耦合电流会增加交流损耗等问题。这使得对导体和线圈性能的定量把握变得困难。这是因为导体中的电流分布是不可控制的。我们对控制导体中电流分布的导体进行了开发研究。通过对导线中电势分布的优化，可以设计出既能保证交流损耗又能保证稳定性的压紧型电缆。首先，通过延长绞线的捻距，绞线中的电动势通过交变曲线被抵消。减少总交流损耗的原型导体已经制造出来。实际测量了交流损耗，并验证了效果。然而，为了考虑作为大型超导线圈的导体，如核聚变实验装置，需要收集压实的股电缆并给予机械加固等。此外，在传导冷却型线圈的情况下，为了在脉冲操作时阻止线圈温度上升，有必要考虑作为高比热的导体，它将比热给予分数而不是形成绞合线。用低纯度铝挤压压缩股缆的导体实际上是一个例子，它聚集了形成股缆。导体构成大尺寸的圆形截面导体。通过对导线进行绞绕，在导线宽侧平行加磁场，可以大幅度降低线圈的交流损耗。通过这些实验和分析结果，控制了导线中的电流分布，建立了低交流损耗和高稳定性相协调的超导导线设计技术。少

In the superconducting conductor which cannot control a current distribution and the contact resistance between strands like a cable-in-conduit conductor (CICC), the event, which is not assumed at the time of a design, may occur such as an enhancement of AC loss by the coupling current ofa long time constant etc. It makes difficult quantitive grasp of a conductor and coil performance. This is because the current distribution in a conductor is not controllable. We have performed development research of the conductor which controlled the current distribution in a conductor. The compacted strand cable to which the position and orbital of each strand clarified is easy to control the current distribution in a conductor, and a design of the conductor which reconciled the AC loss and the stability is possible for it by optimizing the electric-potential distribution in a conductor. First, by lengthening the twist pitch of a strand, the electromotive force in the strand by the alternating-curre … More nt magnetic field and the electromotive force of a stranded cable were canceled. The prototype conductor which reduces a total AC loss has been manufactured. The AC loss was actually measured, and the effect was proved. However, it is necessary to gather a compacted strand cable and to give mechanical reinforcement etc., in order to consider as the conductor of large-sized superconducting coils, such as a nuclear-fusion experimental device. Moreover, in the case of a conduction cooled type coil, in order to stop the coil femperature rise at the time of pulse operation, it is necessary to consider as the conductor of the high specific heat which gave the specific heat to fractions other than a forming stranded wire. The conductor which extrudes a compacted strand cable with low purity aluminum really builds as an example which gathers a forming stranded cable. The conductor constitutes a large-sized conductor with circular cross-sectional shape. By the twisted winding of a conductor so that a magnetic field may be added in parallel with the broad side of a compacted strand cable in this conductor showed that the AC loss as a coil could be reduced sharply, From these experiments and the analysis result, the current distribution in a conductor was controlled and the design technique ofa superconducting conductor in which the low AC loss and the high stability were reconciled was established. Less