Quench protected structured (QPS) superconducting cables, methods of fabricating the same, and methods of bending the same are disclosed. The methods of bending the QPS superconducting cables can be employed to produce windings. The QPS superconducting cables can rapidly drive a distributed quench to a normal conducting state in a superconducting cable if a region of the cable spontaneously quenches during high current operation.

Quench protected structured (QPS) superconducting cables, methods of fabricating the same, and methods of bending the same are disclosed. The methods of bending the QPS superconducting cables can be employed to produce windings. The QPS superconducting cables can rapidly drive a distributed quench to a normal conducting state in a superconducting cable if a region of the cable spontaneously quenches during high current operation.

The present disclosure relates to DC transmission. Some embodiments may include a device for DC transmission comprising: a superconducting transmission line including a superconducting conductor element; and a cooling device for cooling an inner region of the transmission line with a fluid coolant to a temperature below a critical temperature of the superconducting conductor element. The superconducting transmission line may comprise a vacuum-insulated sleeve thermally isolating the inner region of the transmission line from a warmer outer surrounding area. The cooling device may comprise a feed device feeding coolant at an end region of the transmission line into the inner region of the transmission line. The transmission line may be free of internally arranged feed devices for feeding coolant at locations away from the end region.

A method for forming superconducting connection structure between at least two superconducting wires is disclosed, where each wire includes at least one superconducting filament. An end piece of each superconducting wire may be positioned inside a cavity of a pressing tool. A contacting material including MgB2 and/or a precursor material for MgB2 may also be positioned inside the cavity. Pressure may be applied to the contacting material through the pressing tool, and the contacting material may be heated inside the cavity. Pressure and heat may be applied simultaneously, at least during part of the process. A superconducting connection structure including at least two superconducting wires, each wire including at least one superconducting filament, and a superconducting connection between the end pieces of the two wires is also disclosed. The connection may be formed of heated and compressed contacting material including MgB2.

A method of manufacturing an MgB2 thin film wire having an optimum average grain size is done by providing an optimum average grain size range to increase a pinning force and improve Jc with respect to the MgB2 thin film wire. In this method, the MgB2 thin film wire is made of an aggregate of MgB2 grains having a columnar structure which alignment is controlled to be in a direction perpendicular to a surface, a ratio of MgB2 to a total volume of the thin film wire is 90% or more, an average grain size of the grains is 30 nm or more and 200 nm or less by forming the MgB2 thin film having a film thickness of 1000 nm or more and 10000 nm or less in the lateral direction, and the average grain size of the grains is 40 nm or more and 100 nm or less.

A system and method for fabricating accelerator cavities comprises forming at least two half cavities and joining the half cavities with a longitudinal seal. The half cavities can comprise at least one of aluminum, copper, tin, and copper alloys. The half cavities can be coated with a superconductor or combination of materials configured to form a superconductor coating.

A method for forming superconducting connection structure between at least two superconducting wires is disclosed, where each wire includes at least one superconducting filament. An end piece of each superconducting wire may be positioned inside a cavity of a pressing tool. A contacting material including MgB2 and/or a precursor material for MgB2 may also be positioned inside the cavity. Pressure may be applied to the contacting material through the pressing tool, and the contacting material may be heated inside the cavity. Pressure and heat may be applied simultaneously, at least during part of the process. A superconducting connection structure including at least two superconducting wires, each wire including at least one superconducting filament, and a superconducting connection between the end pieces of the two wires is also disclosed. The connection may be formed of heated and compressed contacting material including MgB2.

A superconducting wire comprises a MgB.sub.2 filament, a base material, a high-thermal expansion metal, and a stabilizing material. The high-thermal expansion metal is a metal (for example, stainless steel) having a higher thermal expansion coefficient at room temperature than the MgB.sub.2 and the base material (for example, iron or niobium). The manufacturing method includes a step of packing a mixed powder in a first metal pipe, a step of performing wire-drawing on the first metal pipe formed of the metal to be the base material, a step of producing a composite wire by accommodating the first metal pipe in a second metal pipe formed of the high-thermal expansion metal and the stabilizing material, a step of performing wire-drawing on the composite wire, and a step of performing heat treatment.