JPH03239308A - Superconducting coil - Google Patents

Abstract

PURPOSE:To generate a strong magnetic field by a method wherein a winding is divided into a plurality of regions in accordance with the direction of a magnetic field generated at the winding part, wire materials of the split region parts are arranged so as to be in a direction in which the deterioration of a critical current density is small and coils in the individual split regions are connected in series. CONSTITUTION:A layer B in which tapes are arranged so as to make the direction of a magnetic field parallel with the surface of the tape is formed. Layers A, C at its inside and outside are connected in series. In the regions A, C of a superconducting coil, ordinary straight tape wire materials are solenoid-wound; in the region B, a tape wire material which has been bent in advance to a curvature equal to the curvature at the part is laminated. Consequently, it is possible to prevent a partial critical current density from being deteriorated in the coil and to obtain a uniform critical density of the coil as a whole. Thereby, the strong magnetic field or the compact size of a coil device can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Application Field) The present invention relates to a superconducting coil formed using an oxide superconducting tape wire.

(Prior Art) Conventionally, a metal sheath method has been viewed as a promising method for forming a wire from an oxide superconductor such as B i2<S r, Ca)4Cu30y. In this method, oxide superconductor powder is filled into a metal pipe made of silver or the like, and then subjected to repeated processes such as drawing, rolling, and -axial compression press, and heat treatment, resulting in a high critical current density (J A superconducting tape wire having c) has been obtained. Superconducting coils are formed by winding wires made in this way into coils.

(Problems to be Solved by the Invention) The superconducting tape wire produced by the metal sheath method as described above has a very elongated cross-sectional shape, and the dependence of the critical current density (J c) on the external magnetic field (B). has large anisotropy. Figure 2 shows the relationship between the magnetic field strength and the critical current density (J
It is a graph showing the relationship c). In a magnetic field (B//) parallel to the superconducting tape wire surface, the critical current density (
The critical current density (Jc) deteriorates significantly in the magnetic field (B1) in the direction perpendicular to the tape surface, while the critical current density (Jc) deteriorates little.

Therefore, a case will be considered in which a conventional solenoid coil as shown in FIG. 3 is made using a tape wire having such a Jc-B characteristic. The magnetic field distribution generated when a current is passed through the solenoid coil is shown in Figure 4. In this case, around the shaded area in the coil winding, the magnetic field applied to the superconducting tape wire forming the fill winding is in the direction perpendicular to the wide surface of the tape wire (B
Earth) or something close to it. Therefore, in this region, the critical current density (Jc) of the superconducting tape wire is
The deterioration of

As a result, the current Ic that can be passed through the superconducting coil is determined by the characteristics of the shaded area, and the characteristics of the wire cannot be fully utilized in other areas. That is, in areas other than the shaded area, the critical current density (J c
), and cannot generate a strong magnetic field. Furthermore, since a conductor larger than necessary is used, there are problems such as an economical disadvantage.

The present invention provides a method for forming a coil using a superconducting wire material such as an oxide superconducting tape wire material whose critical current density (Jc) has large anisotropy in dependence on an external magnetic field (B). A superconducting coil that has an average critical current density (J c) over the entire coil is created by preventing the application of an external magnetic field (B) in a direction that would increase the deterioration of the critical current density (J c) to the wire. The purpose is to provide.

[Structure of the Invention (Means for Solving the Problems)] The present invention is based on an oxide superconducting tape wire in which the critical current density (Jc) has a large anisotropy in dependence on the external magnetic field (B). When making a superconducting coil using a superconducting wire, the superconducting tape wire is rotated in a region where the magnetic field generated during coil operation acts in a direction that degrades the critical current density (J e) of the superconducting tape wire forming the coil. By arranging the tape wire so that the direction of the magnetic field and the wide surface of the tape wire are parallel, and winding it into a coil so that the influence of the external magnetic field acting on the tape wire is reduced, a partial critical current density of 3- can be achieved. This is a superconducting coil that prevents the deterioration of (J c) from occurring.

(Function) The superconducting coil of the present invention will be explained below based on the drawings. FIG. 1 is a diagram showing an example of the structure of a superconducting coil according to the present invention. A layer of tape is provided in the area corresponding to the shaded area of the solenoid coil shown in FIG. 4 so that the direction of the magnetic field is parallel to the surface of the tape.
and connected in series with the outer layer. In region A of the superconducting coil, a normal straight tape wire is wound into a solenoid. In region B, tape wires bent in advance to a curvature equal to the curvature of this portion are laminated.

As a method for making such a deformed tape wire, the present applicant has already disclosed Japanese Patent Application No. 1-227484 and Japanese Patent Application No. 1-316.
It can be produced by the method disclosed in No. 427.

Then, in a region C further outside of the region C, a normal straight tape wire is solenoid-wound in the same manner as in the region A. and,
These three regions are connected in series to form a coil that can be operated with one current source. In the superconducting coil fabricated in this way, the direction of the magnetic field in the coil winding portion is determined by the critical current density (
The critical current density (JC) of the entire coil is approximately the same as the direction that does not deteriorate J e).
It has a structure that has

[Effects of the Invention] The superconducting coil of the present invention has the advantage that when a superconducting coil is manufactured using a wire material having anisotropy of Jc-B characteristics, such as an oxide superconducting tape wire material, the partial critical current density (
J c) can be prevented from deteriorating, and the critical current density (J c) can be made uniform throughout the coil. As a result, there are effects such as a stronger magnetic field or a more compact coil device.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the structure of the superconducting film of the present invention, Fig. 2 is a graph showing the Jc-B characteristics of the oxide superconducting tape wire, and Fig. 3 is an explanatory diagram showing the structure of a conventional superconducting coil. FIG. 4 is an explanatory diagram showing the state of the magnetic field when a conventional superconducting coil is in operation. Figure 1 (Tesla) Figure 2

Claims (1)

[Claims] (1) In a superconducting coil using a superconducting wire having anisotropy in the dependence of critical current density on an external magnetic field, the winding is divided into a plurality of regions according to the direction of the magnetic field generated in the winding portion, and the The wires in the divided regions are arranged in a direction in which the deterioration of the critical current density is small in view of the anisotropic relationship with the magnetic field, and the coils in each of the divided regions are connected in series. superconducting coil.