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

在不能控制电流分布和线束间接触电阻的超导导体(CICC)中，可能会发生在设计时没有考虑到的事件，如长时间常数的耦合电流增加交流损耗等，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的。我们对控制导体中电流分布的导体进行了开发研究。确定了每股的位置和轨道的紧凑型绞线很容易控制导体中的电流分布，通过优化导体中的电势分布，可以设计出兼顾交流损耗和稳定性的导体。首先，通过加长股线的扭距，交变曲线…使股线中的电动势更多的nT磁场和绞合电缆的电动势被抵消。研制出了降低交流总损耗的导线样机。对交流损耗进行了实际测量，验证了其效果。然而，为了考虑作为大尺寸超导线圈的导体，如核聚变实验装置，需要收集一根紧凑的绞线电缆并进行机械加固等。此外，在传导冷却型线圈的情况下，为了阻止线圈在脉冲操作时的温度升高，有必要将其视为高比热的导体，该比热向形成的绞合线以外的部分提供比热。用低纯度铝挤压紧凑的绞合电缆的导体实际上是用来聚集形成绞合的电缆的例子。该导体构成具有圆形截面形状的大尺寸导体。通过绞合导线绕组，使磁场与绞合电缆的宽边平行，从而大大降低了线圈的交流损耗。根据这些实验和分析结果，控制了导体中的电流分布，建立了兼顾低交流损耗和高稳定性的超导导体的设计技术。较少

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