A NbTi superconducting multicore wire includes a core portion and a first barrier layer arranged around the core portion and composed of a first copper alloy including at least one element selected from Ni or Mn. A filament assembly arranged around the first barrier layer includes NbTi filament assemblies each including at least seven NbTi filaments, embedded in a matrix of a second copper alloy including at least one element selected from Ni or Mn. A second barrier layer is arranged around the filament assembly and composed of the first copper alloy, and a stabilizing layer arranged around the second barrier layer and composed of metal. The NbTi filaments are arranged in circular shapes each having a different diameter, centering on one NbTi filament, and NbTi filaments arranged in a circular shape in an outermost circle being arranged at approximately equal intervals along a circumferential direction.

A variable-structure stacked cable topology includes: a plurality of sections of stacked cables. The plurality of sections of the stacked cables are connected sequentially. The sections of the stacked cables includes a plurality of base tapes at an equal quantity. The plurality of base tapes are connected mutually. At least one of the plurality of base tapes is a superconducting tape. A cable topological structure is formed by sequentially connecting a plurality of sections of stacked cables. Each of the sections of the stacked cables is provided with superconducting tapes or a combination of superconducting tapes and copper tapes to form a variable-structure cable topological structure. By packaging a different number of superconducting tapes in each area, this section of cable can be twisted into a coil in such a way that a critical current of the whole coil can be approximately uniform along a length direction of the cable.

A variable-structure stacked cable topology includes: a plurality of sections of stacked cables. The plurality of sections of the stacked cables are connected sequentially. The sections of the stacked cables includes a plurality of base tapes at an equal quantity. The plurality of base tapes are connected mutually. At least one of the plurality of base tapes is a superconducting tape. A cable topological structure is formed by sequentially connecting a plurality of sections of stacked cables. Each of the sections of the stacked cables is provided with superconducting tapes or a combination of superconducting tapes and copper tapes to form a variable-structure cable topological structure. By packaging a different number of superconducting tapes in each area, this section of cable can be twisted into a coil in such a way that a critical current of the whole coil can be approximately uniform along a length direction of the cable.

In various embodiments, superconducting wires feature assemblies of clad composite filaments and/or stabilized composite filaments embedded within a wire matrix. The wires may include one or more stabilizing elements for improved mechanical properties.

In various embodiments, superconducting wires feature assemblies of clad composite filaments and/or stabilized composite filaments embedded within a wire matrix. The wires may include one or more stabilizing elements for improved mechanical properties.

The present invention provides: a compound superconducting twisted wire in which non-adhesiveness between compound superconducting strands or separation easiness after adhesion is improved while a strength against tension is improved to a degree to be equivalent to or stronger than that of a conventional compound superconducting twisted wire; and a rewinding method thereof. The compound superconducting twisted wire 1 of the present invention includes a plurality of compound superconducting strands 10 being twisted to form a twisted structure, in which each of the compound superconducting strands 10 includes a compound superconductor part 11, a reinforcing part 12 and a stabilizing part 13, in which the compound superconductor part 11 includes a plurality of compound superconducting filaments 15 and a first matrix 16, the compound superconducting filaments 15 each including a compound superconducting phase, in which the reinforcing part 12 is disposed on an outer circumferential side of the compound superconductor part, and comprises a plurality of reinforcing filaments 18 and a second matrix 19, in which the stabilizing part 13 is disposed on at least one side of an inner circumferential side and an outer circumferential side of the reinforcing part. In the compound superconducting twisted wire, a volume ratio of the reinforcing part relative to the compound superconducting strand is larger than a volume ratio of the compound superconductor part relative to the compound superconducting strand, or a metal layer 20 with a thickness of 2 μm or less is formed on a surface of the compound superconducting strand for preventing thermal fusion between the compound superconducting strands.

It is an object of the present invention to provide an MgB.sub.2 wire helping to achieve compatibility between the ease with which superconducting connection is effected and thermal stability. A superconducting wire according to the present invention includes: an elemental wire formed of MgB.sub.2; and a first metal not reacting with Mg. In a section orthogonal to the longitudinal direction of the superconducting wire, the region extending from the center of the superconducting wire to the installation position of the elemental wire is formed by the elemental wire and the first metal.

It is an object of the present invention to provide an MgB.sub.2 wire helping to achieve compatibility between the ease with which superconducting connection is effected and thermal stability. A superconducting wire according to the present invention includes: an elemental wire formed of MgB.sub.2; and a first metal not reacting with Mg. In a section orthogonal to the longitudinal direction of the superconducting wire, the region extending from the center of the superconducting wire to the installation position of the elemental wire is formed by the elemental wire and the first metal.

In various embodiments, superconducting wires incorporate diffusion barriers composed of Ta alloys that resist internal diffusion and provide superior mechanical strength to the wires.

In various embodiments, superconducting wires incorporate diffusion barriers composed of Ta alloys that resist internal diffusion and provide superior mechanical strength to the wires.