JP2938166B2 - Neutral particle injector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a neutral particle injector used for heating plasma of a nuclear fusion reactor.

(Prior Art) As one method of heating plasma of a fusion reactor, a method of driving a high-energy neutral particle beam into plasma has been considered. A so-called neutral particle injector for implementing this method usually accelerates ions emitted from an ion source 1 by a high-voltage accelerating unit 2 and converts the accelerated ion beam 3 into a neutral beam, as shown in FIG. The deflection magnetic field 5 formed by the gasification cell 4 and the magnet is sequentially passed into the plasma of the fusion reactor 6. Then, the ion beam 7 that has not been neutralized by the neutralization cell 4 is separated from the neutral particle beam 8 by the deflection magnetic field 5, and the separated ion beam 7 is guided to the energy recovery device 9. The energy recovery device 9 usually includes a partition wall as shown in FIG.
The ion beam 7 is made incident on an ion collector 12 through an incident hole 11 provided in 10, and the kinetic energy of the ion beam 7 is converted into a current and collected. At this time, the potential of the ion collector 12 is kept higher than that of the partition wall 10 by the power recovery power supply 13, so that the ion beam 7 is incident on the ion collector 12 while being decelerated.

However, the neutral particle injector configured as described above has the following problems. That is, in the case of a practical fusion reactor, the acceleration energy is further increased, so that the ion beam 7 having a high energy of 1 MeV or more is incident on the energy recovery device 9. In this case, the ion collector 12 needs to be kept at a correspondingly high potential. Therefore, it is inevitable that the entire device becomes larger in order to maintain insulation.

(Problems to be Solved by the Invention) As described above, in the conventional neutral particle injector, when an attempt is made to obtain a high-energy neutral particle beam, the insulation of the energy recovery device is strengthened accordingly. Therefore, there is a problem that the size of the entire apparatus is increased due to this.

Therefore, the present invention does not need to particularly enhance the insulation of the energy recovery device even when it is intended to obtain a high-energy neutral particle beam, thereby contributing to miniaturization of the device and improving the efficiency of the device. It is an object of the present invention to provide a neutral particle incident device that can contribute to improvement of the particle size.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, in the neutral particle injector according to the present invention, an ion beam separated by a deflecting magnetic field is passed and the ion beam has An energy recovery device including a high-frequency cavity for converting a part of energy into microwave power and a recovery system for recovering the converted microwave power is provided.

(Operation) Most of the energy of the ion beam that is not neutralized is converted into microwave power while the ion beam passes through the high-frequency cavity. For this reason, the ion beam that has passed through the high-frequency cavity is sufficiently decelerated into a low-energy ion beam. Therefore, it is not necessary to increase the potential of the ion collector for collecting the ion beam.
With the above configuration, even if it is intended to obtain a high-energy neutral particle beam, it is not necessary to strengthen the insulation of the energy recovery device, so that the size of the device can be reduced. Further, since the converted microwave power is recovered by the recovery system, the recovered microwave power can be used again for accelerating the ion beam, and the efficiency can be improved.

(Example) Hereinafter, an example is described, referring to drawings. FIG. 1 shows a schematic configuration of a neutral particle injector according to one embodiment of the present invention. In this figure, the same parts as those in FIG. 3 are denoted by the same reference numerals. Therefore, a detailed description of the overlapping part will be omitted.

The neutral particle injector according to this embodiment differs from the conventional apparatus in the configuration of an energy recovery device 21 that recovers the energy of the ion beam 7 separated by the deflecting magnetic field 5.

The energy recovery device 21 introduces a microwave of an appropriate frequency and power from an RF source 23 to a high-frequency cavity, in this example, a traveling wave tube 22, into which an ion beam 7 whose orbit is bent by the deflection magnetic field 5 is incident. . Therefore, traveling wave tube
The ion beam 7 incident on 22 is bunched by a microwave and decelerated according to the principle of a normal traveling wave tube. In this example, the microwave power converted by the deceleration is recovered by the power recovery power supply 24.

On the other hand, at the exit of the traveling wave tube 22, the ion beam 7 that has passed through the traveling wave tube 22 and has lost much of the energy is, for example,
A deflection magnetic field 25 for deflecting by 90 ° is provided. The ion beam whose trajectory is bent by the deflection magnetic field 25 is incident on an ion collector 27 maintained at an appropriate potential by a power recovery power supply 26. Therefore, of the energy of the ion beam 7, the energy not lost while passing through the traveling wave tube 22 is converted into electric energy and collected. Reference numeral 28 in the figure denotes a beam dump for recovering ions that have not been decelerated while passing through the traveling wave tube 22.

With such a configuration, the ion beam 7 is
When passing through 22, most of the energy of the ion beam 7 is converted into microwave power, and the power recovery power supply 24
Collected at. Accordingly, the ion beam 7 is sufficiently decelerated and passes through the traveling wave tube 22. The passed ion beam of sufficiently low energy is collected by the ion collector 27. As described above, since the ion beam 7 can be recovered by the ion collector 27 in a state where the energy is sufficiently reduced, it is not necessary to increase the potential of the ion collector 27. For this reason, it is not necessary to reinforce the insulation of the energy recovery device 21, so that the size of the device can be reduced.

FIG. 2 shows a schematic configuration of a neutral particle injector according to another embodiment of the present invention. In this embodiment, the same parts as those in FIG. 1 are indicated by the same reference numerals. Therefore, the description of the overlapping part will be omitted.

In this embodiment, the microwave emitted from the ion source 1 is accelerated by a microwave like an RFQ by an acceleration tube 31, and a part of the microwave power required by the acceleration tube 31 is collected by an energy recovery device 21a. Obtained from microwave power.

The ion beam 3 accelerated by the acceleration tube 31 is well bunched. Therefore, the ion beam 7 separated by the deflection magnetic field 5 is also bunched. When the ion beam 7 that has been bunched like a piece is incident on the traveling wave tube 22, microwave power can be extracted from the traveling wave tube 22 without using an RF source. Therefore, no RF source is used in this embodiment.

All or a part of the microwave power extracted from the traveling wave tube 22 is guided by a waveguide 32, and is coupled by a coupler 33 to an RF source 34.
Is combined with the output of Then, the synthesized microwave power is incident on the acceleration tube 31 via the waveguide 35.

In this embodiment, the microwave output passing through the waveguide 32 and the microwave input passing through the waveguide 35 are detected using the directional couplers 36a and 36b and the detectors 37a and 37b, respectively.
These detection outputs are introduced to the controller 38, respectively. When there is no output from the traveling wave tube 22, such as at the time of start-up of the apparatus, the controller 38 controls the coupler 33 so that all of the microwave input to the acceleration tube 31 is supplied from the RF source 34.
Control the degree of coupling. At this time, the microwave output obtained by the traveling wave tube 22 is absorbed by the dummy load 39.
Then, when the output from the traveling wave tube 22 rises, the controller 38 changes the degree of coupling of the coupler 33 so that the output from the traveling wave tube 22 is combined with the output of the RF source 34, and At the same time, the output of the RF source 34 is reduced, and control is performed such that the entire output from the traveling wave tube 22 is incident on the acceleration tube 31 while maintaining the microwave input to the acceleration tube 31 at a required value.

Therefore, in this embodiment, the same effects as those of the above embodiment can be obtained, and the recovered energy can be reused for accelerating the ions, so that the acceleration efficiency can be improved.

The present invention is not limited to the embodiments described above. That is, in the above-described nuclear embodiment, the high-frequency cavity is constituted by a traveling wave tube, but may be constituted by a standing wave tube, a backward wave tube, or a combination thereof.

[Effects of the Invention] As described above, according to the present invention, even if the energy of the neutral particle beam is increased, it is not necessary to increase the insulation strength of the energy recovery device, so that the device can be downsized. Can contribute to

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a neutral particle injector according to one embodiment of the present invention, FIG. 2 is a schematic configuration diagram of a neutral particle injector according to another embodiment of the present invention, and FIG. FIG. 4 is a schematic configuration diagram of a neutral particle injection device, and FIG. 4 is a schematic configuration diagram of an energy recovery device in the device. DESCRIPTION OF SYMBOLS 1 ... Ion source, 2 ... High voltage acceleration part, 3 ... Ion beam,
4 ... Neutralization cell, 5 ... Deflection magnetic field, 6 ... Fusion reactor, 7 ...
Non-neutralized ion beam, 8 ... neutral particle beam, 2
1, 21a: Energy recovery device, 22: Traveling wave tube constituting high-frequency cavity, 23, 34: RF source, 24, 26: Power recovery power supply, 27 ...
Ion collector, 31 ... Accelerator tube, 32, 35 ... Waveguide, 33 ... Coupler, 38 ... Controller.

Claims (3)

(57) [Claims] 1. The method according to claim 1, wherein the ions emitted from the ion source are accelerated by an accelerating means, and the accelerated ions are passed through a neutralization cell and a deflecting magnetic field in order and incident on a target. In a neutral particle injector that is separated from a neutral particle beam by a deflecting magnetic field and the energy of the separated ion beam is recovered by an energy recovery device, the energy recovery device is separated by the deflection magnetic field. It is characterized by comprising a high-frequency cavity for passing part of the energy of the ion beam through the ion beam and converting the energy of the ion beam into microwave power, and a recovery system for recovering the converted microwave power. Particle injector. 2. The high-frequency cavity comprises a traveling wave tube, a standing wave tube,
The neutral particle injector according to claim 1, wherein the neutral particle injector is configured by one of a backward wave tube or a combination thereof. 3. An accelerating tube for accelerating ions emitted from the ion source by using a microwave, and a microwave power collected via the high-frequency cavity, the accelerating tube being configured to reduce an input power of the accelerating tube. 2. The neutral particle injector according to claim 1, further comprising: a part for inputting to the acceleration tube.