JPS645443B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic field generator, and particularly to a magnetic field generator suitable for use in a nuclear fusion device that confines plasma using a magnetic field.

Conventional magnetic field generators of this type are equipped with a coil that generates a magnetic field perpendicular to the torus direction of the plasma, and the coil can be a spiral coil as shown in Figure 1 or a slit coil as shown in Figure 3. is well known.

FIG. 1 is a plan view showing the arrangement of a conventional spiral coil, and FIG. 2 is a sectional view showing the torus of FIG. 1. Spiral coil 1 as shown in the figure
and 2 are arranged continuously in the torus direction on the outer peripheral surface of the vacuum vessel 4 that encloses the plasma 3, and on the outside of these coils 1 and 2 and the turbulent flow heating coil 5 arranged in the same manner as above. A toroidal coil 6 is provided. Reference numerals 10 and 20 are feeders for supplying current to the spiral coils 1 and 2, O indicates the center of the torus, and T indicates the direction of the torus, respectively.

According to the magnetic field generator having such a configuration, since the spiral coils 1 and 2 are continuous in the toroidal direction, it is difficult to incorporate these coils 1 and 2 into the inner diameter of the toroidal coil 6, and the current of the turbulent heating coil 5 is There is a drawback that a large voltage is induced between the coil terminals due to linkage with the leakage magnetic field caused by etc.

In order to overcome this drawback, a magnetic field generator as shown in FIG. 3 has been provided. That is, this magnetic field generating device has a semicircular arc-shaped coil side 70 with a predetermined diameter and a semicircular arc-shaped coil side 71 with a smaller diameter different from the coil side 70 at the ends of each coil 70 and 71. 72 and 73, the coil sides 70 and 71 are arranged at a substantially constant interval, and currents i _A and i _B are supplied from a part of the coil side 70 to the coil sides 70 and 71. feeder 7
4 and a semicircular arc coil device 7B having the same configuration as described above are combined to form a circular shape. If the magnetic field generator has such a configuration,
Since it can be divided, the above two drawbacks can be solved, but since it is not continuous in the torus direction, discontinuous currents i _A and i _B flow in the torus direction at the terminal transition parts 72 and 73 as shown in FIG. 4, and the plasma 3 However, it has the disadvantage of generating an asymmetric magnetic field Be.

[Purpose of the invention]

It is an object of the present invention to provide a magnetic field generating device which eliminates the above-mentioned drawbacks of the prior art, which can be easily incorporated into the inner diameter of a toroidal coil, and which generates less irregular magnetic field that increases in the terminal transition portion current.

[Summary of the invention]

In order to achieve the above object, the present invention is characterized in that generation of an irregular magnetic field is suppressed by overlapping the terminal transition portions of the coil side ends.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 shows the first magnetic field generator according to the present invention.
FIG. 6 is a plan view showing the embodiment, and FIG. 6 is an enlarged front view of FIG. 5 viewed from the direction of arrow P. In the embodiment of the present invention, the same components as in the conventional example are given the same reference numerals, and the description thereof will be omitted. The difference between the first embodiment of the present invention and the conventional example shown in FIG. 3 is that the terminal transition portions 72' of the split coils 7A and 7B
and 73' are stacked in the height direction, and there is no other change in the structure. More specifically, as shown in FIG. 6, in order to stack the transition portions 72' and 73' in the height direction, the thickness 2d of the overlapping transition portions 72' and 73' is the entire coil side 70 or 73'.
It is preferable that the height be approximately the same as the height H of 1.

With this configuration, the generation of the irregular magnetic field magnetomotive force Be explained in FIG. 4 can be eliminated.

FIG. 7 shows another embodiment of the present invention, showing a modification of the terminal transition portions 72' and 73'.
In FIG. 7, two sets of terminal transition parts 72' and 7
3', for example, the terminal transition part 73' is divided into two in the thickness direction of the coil side.
0', and the other end transition portion 72' is sandwiched between the end transition portion 730' and overlapped with each other.

According to this configuration, it is possible to further reduce illegal magnetic fields.

Here, let's consider the generation of an illegal magnetic field at the terminal transition section. In Figure 6, right below the terminal transition part A
The irregular magnetic field Be given by the current flowing through the terminal transition portions 72' and 73' at a point is expressed as _follows :
It is roughly given by equation (1).

Be ₁ = K (1/d-1/d+t) ... (1) where, K: proportionality constant d: distance t: thickness of the conductor at the terminal transition section The irregular magnetic field Be given by this equation (1) is shown in Figure 4. This is not caused by the generation mechanism shown in Figure 1, but is caused by the difference in the distance between the current sources.

Also, when the coils are arranged as shown in Figure 7,
The magnitude of this type of irregular magnetic field is given by the following equation (2).

Be ₂ = K (1/2d-1/d+0.75t +1/2(d+1.5t)) ...(2) Here, as an example, assuming d = 4 [cm] and t = 1 [cm], (1), Let's try to calculate equation (2) numerically.

From equation (1), Be ₁ = 50.0×10 ^-3 K From equation (2), Be ₂ = 5.4×10 ^-3 K If the arrangement is as shown in Figure 7, the irregular magnetic field will be further reduced. I can understand that it is possible.

FIGS. 8 and 9 show still other embodiments of the present invention, which provide the same effects as the configuration shown in FIG. 7. In the embodiment shown in FIG. 8, one side of the coil side 7 is formed into a turn coil, which is arranged in the shape of a sanderch as shown in the figure.

In FIG. 9, regarding the terminal transition part of the split coil, one transition part 730'' is formed in an annular shape, and the other transition part 72' is arranged inside the annular shape to form a coaxial structure. It is something.

〔Effect of the invention〕

As explained above, according to the present invention, two semicircular arc-shaped coil devices are combined to form a circular magnetic field generating device, and the terminal transition portions of the coil sides are overlapped with each other, so that irregular magnetic fields can be generated. This has the effect of eliminating the occurrence of

[Brief explanation of drawings]

FIG. 1 is a plan view showing a conventional magnetic field generator, FIG. 2 is a cross-sectional view of the torus in FIG. 1, FIG. 3 is a plan view showing another example of a conventional magnetic field generator, and FIG. FIG. 3 is an explanatory diagram illustrating a mechanism in which an irregular magnetic field magnetomotive force is generated by a current at the terminal transition portion; FIG. 5 is a plan view showing an embodiment of the magnetic field generator according to the present invention;
FIG. 6 is an enlarged front view of the terminal transition portion of FIG. 5 viewed from the outside diameter side of the torus, FIG. 7 is a front view showing another embodiment of the present invention, and FIG. 8 is a further embodiment of the present invention. FIG. 9 is a front view showing another embodiment of the present invention. 70...Coil side, 71...Coil side, 72 and 73...Terminal transition portion, 74...Feeder, Be
...irregular magnetic field magnetomotive force, i _A and i _B ... current.

Claims (1)

[Scope of Claims] 1. A first coil side having a semicircular arc shape with a predetermined diameter and a second coil side having a semicircular arc shape having a different diameter from the first coil side having a terminal transition portion at the ends of both coil sides. A semicircular arc coil device is provided, in which both coil sides are connected at approximately constant intervals, and a feeder is provided for supplying current to both coils from a part of the outer coil side of the coil side. A magnetic field generating device comprising two pieces combined in a circular shape, characterized in that two sets of terminal transition portions are overlapped with each other in the thickness direction of the coil sides. 2. In the magnetic field generating device according to claim 1, one of the two sets of terminal transition portions is divided into two in the thickness direction of the coil side, and the other terminal transition portion is connected to the one terminal end. A magnetic field generator characterized by being sandwiched between transition parts and stacked on top of each other.