A superconducting wire according to one embodiment of the present disclosure includes: a substrate having a first surface and a second surface; a superconducting layer having a third surface and a fourth surface; and respective coating layers. The second surface is opposite to the first surface. The fourth surface is opposite to the third surface. The superconducting layer is disposed on the substrate such that the third surface faces the second surface. The respective coating layers are disposed on the first surface and the fourth surface. Adhesion strength between the substrate and the coating layer disposed on the first surface is lower than adhesion strength between the superconducting layer and the coating layer disposed on the fourth surface.

A superconducting wire according to one embodiment of the present disclosure includes: a substrate having a first surface and a second surface; a superconducting layer having a third surface and a fourth surface; and respective coating layers. The second surface is opposite to the first surface. The fourth surface is opposite to the third surface. The superconducting layer is disposed on the substrate such that the third surface faces the second surface. The respective coating layers are disposed on the first surface and the fourth surface. Adhesion strength between the substrate and the coating layer disposed on the first surface is lower than adhesion strength between the superconducting layer and the coating layer disposed on the fourth surface.

A tokamak comprising a vacuum chamber, a toroidal field coil, and a solenoid. The solenoid is wound around the toroidal field coil within a central column region of the tokamak. The solenoid comprises an inner portion and two outer portions. The inner portion comprises windings extending axially for a first distance either side of the midpoint of the length of the solenoid. The outer portions, each comprise windings extending axially from an end of the inner portion. The inner portion has a number of turns per unit length which is greater than a number of turns per unit length of the outer portion.

A tokamak comprising a vacuum chamber, a toroidal field coil, and a solenoid. The solenoid is wound around the toroidal field coil within a central column region of the tokamak. The solenoid comprises an inner portion and two outer portions. The inner portion comprises windings extending axially for a first distance either side of the midpoint of the length of the solenoid. The outer portions, each comprise windings extending axially from an end of the inner portion. The inner portion has a number of turns per unit length which is greater than a number of turns per unit length of the outer portion.

A magnetic field concentrating or guiding device can include one or more coils, and one or more foil, tape and/or bulk superconductor structures disposed in one or more predetermined positions with relation to the coils. The one or more superconductor structures can form one or more magnetic field carrying regions. During operation, current passing through the one or more coils can generate one or more magnetic fields that are compressed or guided in the magnetic field carrying regions.

A superconducting coil device includes a vacuum vessel, a superconducting coil located inside the vacuum vessel, a heat shield surrounding the superconducting coil within the vacuum vessel, and an electric current introduction line for introducing an electric current into the superconducting coil. The electric current introduction line includes an outer current lead part located outside of the heat shield, within the vacuum vessel, and thermally coupled to the heat shield, and an inner current lead part located inside of the heat shield and connecting the outer current lead part to the superconducting coil. The outer current lead part includes a main body serving as an electric current path to the superconducting coil, an insulation layer that covers the main body, and a heat shield layer that covers the insulation layer and has a lower emissivity than the insulation layer.

A superconducting coil device includes a vacuum vessel, a superconducting coil located inside the vacuum vessel, a heat shield surrounding the superconducting coil within the vacuum vessel, and an electric current introduction line for introducing an electric current into the superconducting coil. The electric current introduction line includes an outer current lead part located outside of the heat shield, within the vacuum vessel, and thermally coupled to the heat shield, and an inner current lead part located inside of the heat shield and connecting the outer current lead part to the superconducting coil. The outer current lead part includes a main body serving as an electric current path to the superconducting coil, an insulation layer that covers the main body, and a heat shield layer that covers the insulation layer and has a lower emissivity than the insulation layer.

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.

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.

To provide a superconducting magnet apparatus with a structure which can prevent an increase in apparatus size even when a number of connection portions serving to connect superconducting wires is great. The superconducting magnet apparatus includes a first wiring-holding portion (tubular body (12)) extending from a bobbin (6) in an axial direction of a superconducting coil (1) and a second wiring-holding portion (joint plate (13)) which is provided on a same side in the axial direction as the tubular body (12), extends in a direction intersecting with the axial direction, and has a greater diameter than that of the bobbin (6) and the tubular body (12). Superconducting wires (7a to 11a) which extend from the superconducting coil (1) and connect to one another are spirally wound on the tubular body (12) and fastened to a groove (13a) formed on the joint plate (13).