| 摘要 |
PROBLEM TO BE SOLVED: To moderate the drift caused in a superconductive coil by differing the interlayer stranding pitches of a multilayer structure having a strand wire structure stranding-up a number of superconductive strands. SOLUTION: A sheathing layer 4 consisting of Cu, aluminum, stainless or the like is formed around a superconductive strand layer 9. The superconductive strand layer 9, which is formed by winding a plurality of superconductive strands 1 in multilayer, consists of n-layer superconductive strands from the first layer in the center to the n-th layer on the outermost layer. In order to minimize the twisting as the whole superconductor, the strands are twisted less in the layer closer to the center, and twisted more in the layer closer to the outside. Otherwise, the twisting is not performed at all in the layer closer to the center, and the twisting is performed in only the layer close to the outside. The above procedure is reversed, whereby the connecting coefficient can be minimized. The drift is hardly caused by the reduction in connecting coefficient, and the unevenness of current distribution between strands is prevented. |
