JPS6165407A - Superconductive device - Google Patents

Abstract

PURPOSE:To obtain the high stability of superconductive characteristics by decreasing a current density to prevent a rise of a magnetic field by composing a cross-sectional area of superconductive wire on the side of end part of a superconductive solenoid coil more widely than that of the side of central part. CONSTITUTION:A superconductive solenoid coil 11 is wound on a winding frame 5. A superconductive wire 41a is wound 2 on the terminal side, for example, 2 turns of winding and it is composed of a superconductor 21a buried in a stabilizing member 31. The cross-sectional area of a superconductive member 21a on the side of end part is composed more widely than that of the superconductor 21b on the side of central part thereby decreasing a current density of the superconductive wire 41a on the side of end part.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a superconducting device equipped with a superconducting tornoid coil constructed by winding a superconducting wire with a thin cross-sectional shape around a winding frame, and particularly relates to a superconducting device equipped with a superconducting coil having a thin cross-sectional shape and wound around a winding frame. This relates to means for suppressing the local increase in magnetic field at the end of a solenoid coil.

[Conventional technology]

Conventionally common devices of this type are shown in Figures 1 and 2.
In Figure 0, (1) is a superconducting solenoid coil, which is a superconducting wire (4) having a relatively thin i-plane shape formed by embedding a superconductor (2) in a stabilizing material (3).
is wound around a winding frame [6] to form a cylindrical shape.

(6) is a cryostat that accommodates this superconducting solenoid (1).

Next, the operation of the thin superconducting solenoid coil (1), which has a small coil thickness relative to the 0 cylindrical diameter, has been developed in recent years, for example, by C0N8TRUCTION ANDTES.
T OF THE CELLOTHIN-WAL
L 5 OLENOID (1980, Acl v,
Cryog, Eng, 25) P175~P
As shown in 184, it is used in the field of high-energy physics to elucidate elementary particles by colliding high-momentum elementary particles with each other, so-called particle collision devices. It is configured. Moreover, its constituent materials, except for the superconductor (2), are designed to have aluminum, carbon, etc. as their main components, and are designed to allow good particle penetration. Further, it is natural that the superconductor (2) also has an extremely high current density so as not to increase its cross-sectional area more than necessary. When this superconducting solenoid coil /l' (1) is in full operation, current flows only through the superconductor (2) of the superconducting wire (4), and normally does not flow through the stabilizing material (3).

The current that flows through the stabilizing material (3) is bypassed when the superconductor is broken due to some kind of disturbance.
This is to encourage the return to superconductivity as shown on page 65. In this way, since the superconductor (2) has an extremely small cross section compared to its diameter, especially its ends:
This generates a high magnetic field. This is a kind of edge effect, and similar phenomena can be found, for example, in the theory of electromagnetic phenomena (Showa 1).
(1999, Takeyama Seizo, Maruzen Publishing) P2S5 You can see this. That is, when it is a semi-infinite plane, σ--ψ is given and the electric field becomes infinite. If the wall thickness is infinitesimal, it is a superconducting solenoid carp/
The end magnetic field of l/(1) becomes infinite and generally remains at a finite value due to the finite thickness, but it cannot be denied that it becomes quite high.

In conventional superconducting devices constructed as described above, a rise in the magnetic field at the end of the superconducting solenoid coil is inevitable, and this is especially true in the case of superconducting where the current limit depends on the strength of the magnetic field being experienced. can sometimes be fatal. In other words, even if the maintenance of superconductivity is sufficiently stabilized, if superconductivity breaks down in some areas, there is a high possibility that this will spread as a chain reaction. It is necessary for the equipment to take sufficient measures against this.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it is possible to increase the current density by making the cross-sectional area of the superconducting wire on the end side of the superconducting solenoid coil larger than that on the central side. The purpose of the present invention is to provide a superconducting device that can prevent the rise of the magnetic field and obtain the high stability of superconducting characteristics.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. Iζ. In Fig. 8, (2) is the superconducting solenoid coil /l/ wound around the winding frame (5), (txa), (ttb) is the end side of the superconducting solenoid coil (1), the center side, ( 41
A) is a superconducting wire with, for example, two turns on the end side, and is composed of a superconductor (21a) and a stabilizing material (6 and ζ) embedded therein. (41b) is the superconducting wire on the center side,
It is composed of a superconductor (21b) embedded in a stabilizing material. By the way, the superconductor (21a) on the end side
The cross-sectional area of the superconducting wire (41a) is larger than that of the superconducting wire (21b) on the center side, and the superconducting wire (41a) on the end side
The current density is lowered.

By increasing the cross-sectional area in this way, the current density decreases in inverse proportion to this, so if we assume that the same superconductor properties are abundant, the superconductivity limit (a margin is secured for this) That will happen.

Furthermore, a lower current density means that the magnetic field itself experienced by the superconductor decreases, as shown by the Biot-Saber law, and this phenomenon also has a better effect on the superconducting limit. Sairasu.

Therefore, the stability of superconducting operation can be easily ensured, and the cross-sectional area of the superconductor on the central part side of the superconducting solenoid coil can be sufficiently reduced, which improves the stability and economy of the superconducting solenoid coil as a whole. Furthermore, a method for freezing the superconducting solenoid coil can be obtained.

Another way to increase the cross-sectional area of the superconducting wire (41a) is to use two or more turns of the superconducting wire (41a) in parallel, as shown in FIG. It is also possible to equivalently increase the area, and as shown in Fig. 5, the superconducting wire (41a)
It is also possible to equivalently increase the cross-sectional area of the superconductor (2ta) by stacking them in the radial direction or by using them in parallel, and the same effect as in the above embodiment is achieved.

〔Effect of the invention〕

As described above, according to the present invention, the cross-sectional area of the superconducting wire on the end side of the superconducting solenoid coil is configured to be larger than that on the center side, so that the current density is lowered, so that it is possible to prevent the temperature of the magnetic field from rising. It is possible to obtain high stability of superconducting properties.

[Brief explanation of the drawing]

FIG. 1 is a sectional side view showing a conventional superconducting device, FIG. 2 is an enlarged sectional side view of section A in FIG. , 4th
5 and 5 are enlarged cross-sectional side views of essential parts showing superconducting devices according to other embodiments of the present invention. In the figure, C5) is a winding frame, (6) is a superconducting solenoid coil, (1] a) and (ub) are the end side and center side of the superconducting solenoid coil, (21a) and (21b) are superconductors, 0]) is a stabilizing material, and (41a) and (41b) are superconducting wires. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (4)

[Claims] (1) In a superconducting device equipped with a superconducting solenoid coil configured by winding a superconducting wire with a thin cross-sectional shape around a winding frame, the cross-sectional area of the superconducting wire on the end side of the superconducting solenoid coil is larger than that on the center side. A superconducting device characterized by having a large cross-sectional area. (2) The superconducting device according to claim 1, wherein the superconducting wire on the end side of the superconducting solenoid coil is a plurality of superconducting wires, and the cross-sectional area of the superconductor of the superconducting wire is increased. (3) The superconducting wire on the end side of the superconducting solenoid coil is composed of a plurality of superconducting wires in parallel, and the cross-sectional area of the superconductor of the superconducting wire is equivalently increased as claimed in claim 1. The superconducting device described. (4) Claim 1, characterized in that the superconducting wire on the end side of the superconducting solenoid coil is made by stacking a plurality of superconducting wires in the radial direction to equivalently increase the cross-sectional area of the superconductor of the superconducting wire. The superconducting device described.