JPS6165412A - Superconductive device - Google Patents

Abstract

PURPOSE:To restrain a local rise of a magnetic field in the end part of a superconductive solenoid coil by arranging a magnetic circuit member in the end part of a superconductive solenoid coil in the shortest distance within a permissible limit. CONSTITUTION:The superconductive wire 4 having a thin cross-sectional shape which is formed by burying a superconductor 2 in a stabilizing material 3 is wound on a wiring frame 5 to obtain a cylindrical solenoid coil 1. Then the coil 1 is contained in a cryostat 6 and it is arranged near a magnetic circuit member 8 for magnetic shielding in the shortest distance within a permissible limit. Consequently a strength of a magnetic field becomes as shown by a line (a) and a local rise of a magnetic field in the end part can be restrained.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a superconducting device equipped with a super 7-conducting solenoid coil constructed by winding a super conducting wire around a winding frame with a thin-walled cross-sectional shape, The present invention relates to means for suppressing a local increase in magnetic field at the end of a solenoid coil.

[Conventional technology]

Figures 1 and 2 show two common baits for this type of bait.
As shown in the figure. In the figure, (1) is a superconducting solenoid coil, which is a superconducting solenoid coil (U) that stabilizes the conductor (2).
4) is wound around a winding frame (5) to form a cylindrical shape. (
6) is a cryostat that accommodates this super single-conducting solenoid coil (1), and (7) is a magnetic circuit member that magnetically shields the whole, and is mainly made of iron.

Next, I will explain about ζ creation. Thin-walled solenoid coil (1) with a small coil thickness compared to the cylindrical diameter
If, in recent years, for example, C0N5TRUCTION AND
TEST OF THE CELLOTHIN-WAL
L 5OLENOID (1980.

Adv, Cryog, Eng, 25) P175~
As seen on page 184, in the field of high-energy physics, high-momentum elementary particles collide with each other. The walls are made as thin as possible. Furthermore, except for the superconductor (2) and the magnetic circuit member (7), its constituent materials are mainly composed of aluminum, carbon, etc., and consideration has been given to ensuring good penetration of n-particles.
ing. Further, it is natural that the superconductor (2) also has an extremely high current density so as not to make the cross section thicker than necessary. When this superconducting solenoid coil (1) is operated, the circulating current remains only in the superconductor (2) of the superconducting wire (4), and usually does not flow in the stabilizing material (3). The current that flows through the stabilizing material (3) is bypassed when the superconductor breaks due to some kind of disturbance, for example, the IEEJ University Lecture: Superconductivity Engineering (1971, Institute of Electrical Engineers of Japan) P60-P
This is to encourage the return to superconductivity as shown in Figure 65.

Since the superconductor (2) has an extremely small cross section compared to its diameter, it generates a high magnetic field, especially at its ends. This is a kind of edge effect, and a phenomenon similar to this n is, for example, in the electromagnetic phenomenon theory, where the magnetic field becomes infinite. If the wall thickness is infinitely small, the end magnetic field of the superconducting solenoid coil (1) will be infinite, and although it generally remains at a finite value due to the finite thickness, it cannot be denied that it becomes quite high.

In addition, the magnetic flux inside the superconducting solenoid coil (1) is passed through a magnetic circuit member (7 and 5) placed around it and a magnetic circuit member for morale shielding (7 and 5) to form a closed circuit, so that there is not much leakage to the outside. There is.

Conventional superconducting equipment is configured as described above, so
An increase in the magnetic field at the end of the superconducting solenoid coil (1) is unavoidable, and this is sometimes fatal, especially in the case of superconductors where the downstream limit depends on the strength of the magnetic field being experienced. In other words, even if the maintenance of superconductivity is sufficiently stabilized, if some part of the superconductivity breaks down, there is a high possibility that this will spread like a chain reaction, and the In large-sized devices, sufficient countermeasures against this problem are necessary.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and by arranging the magnetic circuit member at the end of the superconducting solenoid coil at the shortest distance within the allowable limit, the magnetic circuit member is placed at the end of the superconducting solenoid coil. The purpose is to provide a superconducting device that can suppress the rise in local magnetic field.

[Embodiments of the invention]

Hereinafter, one embodiment □ of this invention will be explained with reference to the drawings. m
Figure 3 shows the placement of the superconducting wire (4) at the end of the superconducting solenoid coil (1), where (8) is placed as close as possible to the end of the superconducting solenoid coil (1), i.e. at the shortest distance within the permissible limit. It is a magnetic circuit member for morale shielding, and materials such as iron, which are inexpensive and have good magnetic permeability, are mainly suitable. If there is a member with high magnetic permeability in this way, it becomes possible to imagine a virtual number ζ in which the surface of the monthly interest rate is just a mirror surface, and the superconducting solenoid coil in that image is set at 0°C. Figure 4 shows the qualitative pattern of the experienced magnetic field in the conductor, and a shows the strength of the magnetic field as a function of the axial position when there is no superconducting solenoid coil dll in the image, and point E is the superconducting It corresponds to the leading edge of the superconductor (2) of the wire (4).

Also, al is the strength of the magnetic field produced by the superconducting solenoid coil αB in the image, and i is the composite field of a and al.

The image and its effects can thus be explained qualitatively as follows. That is, when no image is considered, the strength of the magnetic field can be considered to be as shown in FIG. 4a, where all the magnetic fields on the left side of FIG. 3 are integrated at point E.

Next, if an object with high magnetic permeability is placed in the vicinity, for example, a mirror image of the surface of the object, as shown in Denken Kiyu Phenomenon Theory (1945, Takeyama Setsu-san, Maruzen Publishing), pages 873-375, can be obtained. Or imagine it as a virtual image,
This effect extends to the magnetic field distribution a. This effect is like reversing a and b, and in the clear image El at point E, the part of the reverse direction is a.
- Be like the al that you have. Therefore, the actual magnetic field distribution of the coil operator Cii becomes C, and as a result, a magnetic field B is obtained which is lower than the magnetic field Byh when there is no image at point E.

By reducing the magnetic field experienced by the conductor due to the edge effect in this way, the stability of the superconductor increases.

〔Effect of the invention〕

As described above, according to the present invention, the n l, t' Fa air circuit iH is distributed to the IM of the superconducting solenoid coil at the shortest distance within the allowable limit. Since the increase in Vl can be suppressed and therefore the superconducting stability increases, the effect of obtaining a superconducting device that is simple, inexpensive, and highly stable in terms of Vl is obtained as a whole.

[Brief explanation of drawings]

Fig. 1 Ii A cross-sectional side view showing a conventional super-conductor bag, Fig. 2
Figure Ii is an enlarged cross-sectional side view of part A in Figure 1, Figure 3 is an enlarged cross-sectional side view of main parts showing a rice grain conduction device according to an embodiment of the present invention, and Figure 4 is an end portion of a superconducting solenoid coil according to the present invention. FIG. 3 is a characteristic diagram showing the 8-field reduction effect. In the figure, (1), αl) i, t i 'f4 conducting solenoid coil 4), (41) Ii super conducting wire, (
5) is a winding frame, and (8) l; i is a magnetic shielding member. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] In a superconducting device equipped with a cylindrical superconducting solenoid coil constructed by winding a superconducting wire with a thin cross-sectional shape around a winding frame, a magnetic circuit member is disposed at the end of the superconducting solenoid coil at the shortest allowable distance. A superconducting device featuring: