JPS63304605A - Coil device - Google Patents

Abstract

PURPOSE:To obtain a coil device which has only small error magnetic fields and has no heat and strength problems of the feeder section, by providing a cutout in the coil conductors in the neighborhood of the feeder line in the feeder section of a coil device. CONSTITUTION:A cutout 7 is formed in conductors 6a, 6b, and the currents 8, 10 flowing in a coil conductor 2 and a feeder line 3 form an error magnetic field current loop. Also, the currents flowing in the conductors 6a, 6b have their paths curved by the cutout 7, forming an error magnetic field current loop generated by the currents 9 and 10 flowing in the conductors 6a, 6b. this error magnetic field current loop reversely circulates and the directions of the error magnetic fields generated are different, so the error magnetics fields can be made small by adjusting the size of the error magnetic field current loop by the depth of the cutout 7 to offset the error magnetic fields. With this, a coil device can be obtained which has small error magnetic fields and has no weak point in the strength and heat in the feeder section.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a coil device, and particularly relates to a coil device used in helical coils, toroidal coils, poloidal coils of nuclear fusion experimental equipment, charged particle accelerators, etc. It is something.

[Conventional technology]

2. Description of the Related Art Conventional coil devices, particularly structures of their power feeding sections, are shown in FIGS. 5 to 8. FIG. 5 shows the structure of a general coil feeding section, and FIG. 6 shows a structure in which the feeding wire is made thinner than the conductor thickness in order to reduce the error magnetic field generated by the feeding section.

Furthermore, as a structure that improved these, JP-A-58-134
There is a device having the structure shown in FIGS. 7 and 8 shown in Japanese Patent No. 405. In these figures, (1) is the coil, (2
) is a coil conductor, (3) is a power supply line, (4) is an arrow indicating the current direction, and (5) is a slit provided at the corner of the power supply section.

Next, the operation will be explained. In order to generate the required magnetic field, the coil is energized through a power supply line (3).

Conventionally, when performing plasma confinement, plasma control, and deflection of charged particles using the magnetic field created by the coil of this type of device,
Generally, if there is a ``magnetic field disturbance'' called an error magnetic field, it will have a negative effect on plasma confinement, control, deflection of charged particles, etc., so it is necessary to reduce the error magnetic field as much as possible. For this reason, the winding precision and arrangement precision of the coil are not necessarily required to be very high, and it is necessary that the magnetic field created by the lead section does not have an adverse effect on the normal magnetic field created by the coil section.

In the case of FIG. 5, the current required is a circular current.

When the ideal circular current is subtracted from the actual current including the current flowing through the power supply line (3), a current component as shown by the closed curve (a) in FIG. 9 remains in the power supply section. This is the error magnetic field current loop that causes the error magnetic field.

[Problem that the invention seeks to solve]

The conventional coil device as described above is as shown in Fig. 5.
This error magnetic field current loop is large and may adversely affect device functions such as plasma confinement. Although the one shown in FIG. 6 is improved over the one shown in FIG. 5, it still produces an error magnetic field loop similar to the one shown in FIG. 5, and cannot be applied to devices requiring high magnetic field accuracy.

On the other hand, in the power feeding section of the devices shown in Figures 7 and 8, the stain current distribution is adjusted using slits, and as shown in Figure 10, the error magnetic field current loop is made small and generated by a current loop in the opposite direction. This is done to cancel out the error magnetic field that occurs.

However, with this structure, current concentrates in the slit portion of the power feeding section, and this portion becomes hot due to Joule loss. In addition, the strength is extremely weakened due to the slits, and there is a problem that it cannot be applied to a coil device where a large electromagnetic force acts.

This invention was made to solve the above-mentioned problems, and aims to provide a coil device with a small error magnetic field and free from thermal and strength problems in the power feeding section.

[Means for solving problems]

The coil device according to the present invention has a coil conductor in the vicinity of the power supply line cut out in the power supply section.

[Effect]

In this invention, the current path is changed by the cutout in the conductor near the feeder line, thereby canceling out the error magnetic field generated by the feeder line.

〔Example〕

FIG. 1 shows an embodiment of the present invention, in which (6
a) is the conductor adjacent to the feeder line (3), (6b) is the conductor (
This is the conductor adjacent to 6a). Conductor (6a).

A notch (7) is formed in (6b).

In addition, the same reference numerals as in FIGS. 5 to 8 indicate the same parts.

With the above configuration, the coil conductor (2) and the feeder line (3
) forms an error magnetic field current loop shown in FIG. In Figure 2, (8) is the actual current, (1
0) is the current component remaining after subtracting the ideal current from the actual current.

Further, the path of the current flowing through the conductors (6a) and (6b) is bent by the notch (7). Figure 3 shows currents (9) and (10) flowing through conductors (6a) and (6b).
) is the error magnetic field current loop created by The error magnetic field current loops in Figures 2 and 3 are in opposite directions, and the direction of the generated error magnetic field is different. Therefore, the size of the error magnetic field current loop in Figure 3 can be determined by the depth of the notch (7). Adjust,
The error magnetic field generated by the error magnetic field current loop in Figure 2 and the third
By canceling out the error magnetic field generated by the error magnetic field current loop shown in the figure, the error magnetic field can be made very small.

Compared to the structure shown in FIG. 8, the structure described above does not have the slit (5), so the strength of the power feeding section is improved, and the concentration of current is alleviated, so that temperature rise due to Joule loss can be kept low.

Furthermore, the strength reduction and temperature increase due to the notches (7) in the conductors (6a) and (6b) adjacent to the power supply section are less strict than the strength and temperature increase of the power supply section, and are not the weakest point that determines the performance of the device.

If the notch is made in a circular arc as in the example shown in FIG. 1, or in a boat shape formed by a circular arc and a straight line, the above-mentioned decrease in strength and temperature increase can be prevented from becoming large.

In the above embodiment, the power supply line (3) has a sandwich structure, with four conductors (6a) adjacent to the power supply part.

Although the notch (7) is provided in (6b), many variations are possible in the structure of the power feeding section and the arrangement of the conductor to be cut out.

In another embodiment shown in FIG. 4, there are two feeder lines (3) like the one in FIG. 5, and cutouts (7) for conductors (6) are formed on both sides of the feeder lines (3). Of course, the power supply part is
It is also possible to have a structure as shown in the figure, and even if only one conductor is cut out, it is effective in reducing the error magnetic field.

〔Effect of the invention〕

As described above, according to the present invention, the conductor near the power supply line is cut out to cancel the error magnetic field generated by the error magnetic field current loop of the power supply section, so the error magnetic field is small and the power supply section has a strong This has the effect of providing a coil device with no physical or thermal weaknesses.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a main part of one embodiment of the present invention, FIGS. 2 and 3 are schematic diagrams for explaining the function of the one shown in FIG. 1, and FIG. 4 is a main part of another embodiment. 5 is a perspective view of a conventional coil device, FIG. 6 is a perspective view of a main part of the one shown in FIG. 5, and FIGS. 7 and 8 are a plan view and main part of another conventional coil device. The partial perspective view, FIG. 9, and FIG. 10 are schematic diagrams for explaining the operation of the conventional coil device, respectively. (1) Coil, (2) Coil conductor, (3) Power feed line, (6) , (sa), (sb)... Conductor near the power feed line, (7) Notch. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A coil device in which a notch is formed in at least one coil conductor near a power supply line so as to generate a current loop that cancels an error magnetic field current loop generated by a power supply section. (2) The coil device according to claim 1, wherein the cross-sectional shape of the cutout is either a circular arc or a boat shape formed by a circular arc and a straight line.