JPS6212317Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement in the arrangement and formation of a supporting device and an iron core for an ohmic heating coil for an annular discharge type nuclear fusion device, and improvements in the coil and toroidal coil associated with this improvement.

Conventionally, in the annular discharge type fusion experimental device,
As shown in Fig. 1, an iron core 2 has been inserted into the magnetic path of an ohmic heating coil 1, but there is a need to make the plasma 3 thicker, that is, have a larger cross-sectional radius, and also increase the radius of curvature of the plasma. If the space in the center of the device is severely limited due to the need to make the toroidal coil 5 and its supporting device large enough to withstand the generation of a strong toroidal magnetic field, a so-called air-core structure is adopted in which the insertion of an iron core is abandoned. I've been In the case of this type of air-core structure, the ohmic heating coil 1, which induces a plasma current by an electromagnetic induction effect similar to the action of a transformer, is an air-core coil, so its excitation inductance is extremely small; Plasma induction and ohmic heating are impossible unless a large excitation current is injected from the power source. In this case, the excitation current component required to maintain the magnetic flux of the ohmic heating coil 1 is significantly larger than the component corresponding to the plasma current, that is, the so-called load current component in a transformer, of the current of the ohmic heating coil power supply. This increases the size of the power supply, resulting in drawbacks such as an unnecessarily large capacity of the power supply.

In order to eliminate this drawback, the present invention provides a ferromagnetic column in the center of the device as the most important countermeasure for increasing the excitation inductance of the ohmic heating coil. The present invention is characterized in that it reduces the amount of water, and will be described below with reference to embodiments of the present invention.

FIG. 2 is a diagram for explaining the magnetic path of an ohmic heating coil. It is most important to reduce the magnetic resistance in the inner region of the ohmic heating coil 1, that is, the region 6 in the figure, which accounts for a large proportion of the magnetic resistance of the coil magnetic flux path 9 in this state. In the outer region of the ohmic heating coil 1, the coil magnetic flux can spread over a large space, so that its reluctance is relatively small. Therefore, by inserting a cylindrical or axially symmetrical ferromagnetic column 11 in the inner region, the inductance value of the coil can be made several times to ten times that of the air-core state, and the excitation current required to obtain the same magnetic flux can be increased. It can be set to about one-tenth to one-several fraction of the empty core state. Furthermore, when this type of axisymmetric ferromagnetic column 11 is inserted, the magnetic field of the coil is essentially axisymmetric and contains non-axisymmetric magnetic disturbances that are harmful to the plasma 3. do not have.

Although the inductance can be further increased by placing the ferromagnetic material column 11 in the outer region of the coil as in the conventional fusion device with an iron core, on the other hand, this limits the degree of freedom in observing phenomena and disassembling and assembling the device. This is not desirable because it causes problems such as

FIG. 3 shows an example of the shape of the ohmic heating coil and the inserted ferromagnetic column. By making it a structure,
Most of the magnetic flux leaving the inner region of the coil becomes plasma 3.
The outer region of the plasma 3 is exclusively refluxed without crossing the
Therefore, unnecessary disturbance of the plasma is avoided.

FIG. 4 shows an example of a cross-sectional view of the ferromagnetic column 11, and is used to prevent circumferential eddy currents from flowing in the ferromagnetic column 11 due to temporal changes in the magnetic flux of the ohmic heating coil. As shown in the figure, this is disassembled radially, and an insulator 10 is inserted into the divided portion.

FIG. 5 shows an example of the overall configuration of an apparatus to which the present invention is applied. In the figure, the toroidal coil 5 receives an electromagnetic expansion force due to the generated magnetic field, so the ferromagnetic column 11 and the frame part 7
and 8 surround the toroidal coil 5 to counteract this electromagnetic force. In this structure, the ferromagnetic pillar 11 has the function of mechanically connecting the upper and lower parts of the toroidal coil support devices 7 and 8 to effectively increase the structural mechanical strength of the entire support device. In the present invention, since the ohmic heating coil 1 is made of a ferromagnetic material, the excitation inductance of the ohmic heating coil 1 can be increased as described above. If the relative magnetic permeability of the ferromagnetic column 11 is, for example, about several tens of tens, the effect of increasing the excitation inductance is sufficient, and since this type of fusion device is operated intermittently, Eddy current loss,
Since hysteresis loss does not pose a major problem, there are no particularly strict requirements for the electrical resistance and magnetic hysteresis characteristics of the ferromagnetic column 11. In addition, from the viewpoint of structural mechanics, the stress of the ferromagnetic column 11 is designed to be within the allowable stress by suppressing the force sharing between the ferromagnetic column 11 and the other supporting device parts 7 and 8 to an appropriate ratio. can do. Therefore, the ferromagnetic column 11 can have both functions as a structural member and an iron core, as described above. Further, as is clear from FIG. 5, the ferromagnetic column 11 extends vertically in a straight line, while the heating coil 1 of the toroidal coil 5 and the ferromagnetic column 1
1, that is, the part that is in contact with the ferromagnetic column 11 in the figure is the ferromagnetic column 11.
The heating coil 1 extends linearly along the outer surface of the ferromagnetic column 11 in the axis (vertical center line) direction, and the heating coil 1 similarly extends along the outer surface of the ferromagnetic column 11 in the direction of the axis (vertical center line) of the ferromagnetic column 11. It extends linearly in the axial direction of the body column 11. Therefore, a sufficient cross-sectional area of the ferromagnetic column 11 can be ensured, and in conjunction with the fact that it is a ferromagnetic material, the inductance can be further increased.
The stress of ferromagnetic material column 1 is generated uniformly over the entire upper and lower regions, and the stress per unit area is reduced.
Deformation, distortion, etc. of 1 itself can also be controlled.

In addition, in FIG. 5, among the support device parts 7 and 8, the support device 7, which is relatively less likely to interfere with plasma phenomenon observation, may have a shape close to an axially symmetrical structure. Similarly, if this is made of a magnetic material, a magnetic field distribution with fewer harmful lines of magnetic force crossing the plasma 3 can be realized without generating non-axisymmetric magnetic field disturbances as explained in FIG.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an example of the conventional iron-core annular discharge type fusion device, Fig. 2 is an explanatory diagram of the principle of increasing the excitation inductance of an ohmic heating coil, and Fig. 3 is a diagram showing the magnetic column and FIG. 4 is a sectional view showing an example of the shape of an ohmic heating coil, FIG. 4 is an explanatory cross-sectional view of a magnetic column, and FIG. 5 is a configuration diagram showing the overall configuration of an embodiment of the fusion device according to the present invention. In the figure, 1 is an ohmic heating coil, 3 is an annular plasma, 4 is a plasma vessel, 5 is a toroidal coil, 7 and 8 are support devices, and 11 is a ferromagnetic column. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] An annular plasma vessel, a ferromagnetic column provided at the axis of symmetry of the plasma vessel, and a ferromagnetic column wound around the ferromagnetic column and along the outer surface of the ferromagnetic column. a heating coil that extends in a direction and generates a plasma current in the plasma vessel; a portion that is wound around the plasma vessel and the heating coil and located between the ferromagnetic column and the heating coil is the ferromagnetic column; a toroidal coil extending in the axial direction of the ferromagnetic column along the outer surface of the ferromagnetic column;
and a support device connected to the ferromagnetic column to support the toroidal coil and the plasma vessel.