Mirror fusion device

Abstract

The present invention provides a mirror fusion device capable of stably confining high-density plasma.　This mirror fusion device comprises a central vessel 10, a confining magnetic field configuration generation unit 20, and a plasma generation unit 30. The central vessel 10 extends in a longitudinal direction to confine plasma. The confining magnetic field configuration generation unit 20 comprises at least two coils 21, 21 disposed opposite one another and coaxially with the longitudinal direction of the central vessel 10, and generates a confining magnetic field 22 for confining the plasma between the two coils 21, 21. The plasma generation unit 30 is connected to the central vessel 10 between the two coils 21, 21 of the confining magnetic field configuration generation unit 20, and rapidly forms a high-density plasma region inside the confining magnetic field 22.

Description

Mirror-type fusion device

[0001] The present invention relates to a mirror-type nuclear fusion device, and more particularly to a mirror-type nuclear fusion device that confines plasma by a magnetic field.

[0002] A mirror-type fusion device is known for achieving nuclear fusion, which confines plasma using a magnetic field. By placing two coils coaxially facing each other and passing current in the same direction, a magnetic field configuration is created in which the magnetic field is strong near the coils and weaker between the coils. Charged particles in the plasma move while wrapping around the magnetic field lines, but where the magnetic field is strong, the charged particles are repelled as if there were a mirror, and are trapped between the two coils. This is the plasma confinement principle of a mirror-type fusion device.

[0003] The plasma confined in a mirror-type fusion device is generated using, for example, a neutral particle beam, as disclosed in U.S. Patent No. 5,623,299, which uses a low-energy neutral particle beam injected between magnetic confinement coils to generate plasma ions heated by radio frequency electromagnetic waves to a temperature at which fusion occurs.

[0004] Furthermore, for example, Patent Document 2 discloses an apparatus that generates field-reversed configuration (FRC) plasma within a confining magnetic field. Here, FRC plasma is a high-density plasma whose plasma pressure can be maintained solely by a poloidal magnetic field generated by a self-current. In this apparatus, two coils are arranged coaxially opposite each other, with FRC plasma generators arranged opposite each other at both ends, capable of injecting FRC plasma in the axial direction. From the FRC plasma generators arranged opposite each end, FRC plasmas are injected axially toward the confining magnetic field, and then combined in the center via magnetic reconnection.

[0005] In addition, for example, the device disclosed in Patent Document 3 also supplies plasma in the axial direction from a plasma supply source located at the end of two coils arranged coaxially facing each other. Charged particles of the supplied plasma are accelerated by coupling with a strong electric field generated by a betatron flux coil located at the center along the axis, causing magnetic reconnection and forming FRC plasma.

[0006] JP 2023-520020 A U.S. Patent Publication No. 2019 / 0139649 JP 2006-308604 A

[0007] However, in the device that generates plasma using a neutral particle beam, as in the device disclosed in Patent Document 1, it is difficult to form plasma with a sufficiently high density within the confining magnetic field.In addition, the plasma tends to escape to the outside, so it is difficult to stably confine the plasma within the confining magnetic field.

[0008] On the other hand, in the devices using FRC plasma described in Patent Documents 2 and 3, the FRC plasma is a high-density region with a closed magnetic field line structure, so it is possible to stably confine high-density plasma within the confinement magnetic field. However, because anchors, thermal barriers, end sections, etc. are installed at both ends of the confinement magnetic field, in order to supply FRC plasma from the axial direction of the opposing coils, it was necessary to inject the FRC plasma using an FRC plasma generator from a position far from the confinement magnetic field. Therefore, not only was it necessary to address neutrons and thermal loads, but it was also difficult to control the plasma via the magnetic field lines from a position far from the confinement magnetic field.

[0009] For this reason, there was a need for the development of a mirror-type fusion device that could stably confine high-density plasma.

[0010] In view of the above circumstances, the present invention aims to provide a mirror-type nuclear fusion device that can stably confine high-density plasma.

[0011] In order to achieve the above-mentioned object of the present invention, a mirror-type fusion device according to the present invention may comprise: a central vessel extending in the longitudinal direction for confining plasma; a confinement magnetic field configuration generator consisting of at least two coils arranged coaxially and facing each other with respect to the longitudinal axis of the central vessel, the confinement magnetic field configuration generator generating a confinement magnetic field for confining plasma between the two coils; and a plasma generation unit connected to the central vessel between the two coils of the confinement magnetic field configuration generator for forming, within the confinement magnetic field, a plasma region of a predetermined density equal to or greater than the density at which a fusion reaction can be maintained, within a predetermined time that is shorter than at least the diffusion time of the magnetic field or the growth time of MHD instability.

[0012] Here, the plasma generation unit consists of at least a pair of magnetized plasmoid generation devices arranged opposite each other across the longitudinal direction of the central vessel, and the pair of magnetized plasmoid generation devices simultaneously inject plasmoids into the central vessel with momentum that is at least sufficient to penetrate into the confining magnetic field, and cause them to collide within the confining magnetic field, canceling out their momentum and merging to form a plasma region.

[0013] The pair of magnetized plasmoid generating devices may be made up of a plurality of pairs, each pair intermittently injecting a plasmoid in turn.

[0014] Furthermore, when the pair of magnetized plasmoid generating devices simultaneously inject plasmoids, a magnetic field application unit may be provided for applying a magnetic field in a direction that weakens the confining magnetic field.

[0015] The plasma generating unit may be a magnetic field reversed configuration plasma generating device or a reversed field theta pinch device.

[0016] The plasma generating unit may also be a laser ablation device that irradiates a target placed in a central chamber with laser light to form a plasma region of laser ablation plasma within a confining magnetic field.

[0017] Furthermore, it may be equipped with a neutral particle beam injection device for injecting a neutral particle beam into the central vessel for heating the plasma region within the confinement magnetic field and for nuclear fusion reactions, or a radio frequency heating device for heating the plasma region within the confinement magnetic field.

[0018] Furthermore, a repelling portion may be provided for confining fusion-produced particles that escape in the longitudinal direction of the central vessel along the magnetic field lines of the confinement magnetic field.

[0019] Additionally, the reactor may include end portions for extracting energy from fusion product particles that escape longitudinally of the central vessel along the magnetic field lines of the confining magnetic field.

[0020] The mirror-type nuclear fusion device of the present invention has the advantage of being able to stably confine high-density plasma.

[0021] Fig. 1 is a schematic side cross-sectional view for explaining a mirror-type fusion device of the present invention. Fig. 2 is a schematic front cross-sectional view for explaining another example of a mirror-type fusion device of the present invention. Fig. 3 is a schematic side cross-sectional view for explaining the specific overall configuration of a mirror-type fusion device of the present invention. Fig. 4 is a schematic side cross-sectional view for explaining another example of a mirror-type fusion device of the present invention. Fig. 5 is a diagram showing the distribution of field-reversed configuration plasma formed by a mirror-type fusion device of the present invention over time.

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a schematic side cross-sectional view illustrating a mirror-type fusion device of the present invention. Note that the illustrated example is merely a conceptual diagram, and the thickness and length of the walls are not limited to those shown in the drawing. As shown in the drawing, the mirror-type fusion device of the present invention is mainly composed of a central vessel 10, a confinement magnetic field configuration generation unit 20, and a plasma generation unit 30.

[0023] The central vessel 10 is for confining the plasma. The central vessel 10 extends in the longitudinal direction. Specifically, the central vessel 10 has a cylindrical tube shape, and the interior of the central vessel 10 may be kept in a vacuum state or a near-vacuum state.

[0024] The confinement magnetic configuration generator 20 comprises two coils 21, 21 arranged coaxially and facing each other along the longitudinal axis of the central vessel 10. The confinement magnetic configuration generator 20 may be any configuration that generates a confinement magnetic field using two coils 21, 21, so-called mirror coils. In the illustrated example, the coils 21, 21 are arranged on the outer periphery of the central vessel 10, but the present invention is not limited to this and may be arranged on the inner periphery of the central vessel 10. The confinement magnetic configuration generator 20 generates a confinement magnetic field 22 for confining plasma between the two coils 21, 21. Specifically, by passing currents through the two coils 21, 21 in the same direction, a magnetic field configuration is generated in which the magnetic field is strong near the two coils 21, 21 and weak between the coils. Plasma is repelled from the strong magnetic field near the two coils 21, 21, resulting in the confinement of plasma between the two coils 21, 21. In the illustrated example, the confining magnetic field configuration generation unit 20 is shown to consist of two coils 21, 21, but the present invention is not limited to this, and more coils may be arranged coaxially with the longitudinal axis so that the confining magnetic field 22 can be appropriately controlled.

[0025] The plasma generation unit 30 is connected to the central vessel 10 between the two coils 21 of the confinement magnetic field configuration generation unit 20. As shown in the figure, the plasma generation unit 30 of the mirror-type fusion device of the present invention is not disposed on the longitudinal axis of the central vessel 10, but is connected between the two coils 21, i.e., to the outer periphery of the central vessel perpendicular to the longitudinal direction of the central vessel 10. The plasma generation unit 30 rapidly forms a high-density plasma region 35 within the confinement magnetic field 22. That is, the plasma generation unit 30 rapidly forms a closed magnetic field line structure within the confinement magnetic field 22. By forming the plasma region 35 with a closed magnetic field line structure, it is possible to reduce fusion-produced particles that escape in the longitudinal direction of the central vessel 10 along the magnetic field lines of the confinement magnetic field 22.

[0026] Here, the formation of the high-density plasma region 35 at high speed will be explained in more detail. First, forming the plasma region 35 at high speed means forming the plasma region 35 in a predetermined time that is shorter than at least the diffusion time of the magnetic field or the growth time of MHD instability. This predetermined time depends not only on the temperature and density of the plasma but also on the geometric size of the central vessel 10. In one example from a demonstration experiment, the predetermined time was preferably several tens of microseconds, and more preferably about 10 microseconds. In this way, it is sufficient if the plasma region 35 can be formed faster than the diffusion time of the magnetic field or the growth time of MHD instability. Furthermore, the high-density plasma region 35 means a plasma region 35 with a predetermined density that is equal to or higher than the density at which a nuclear fusion reaction can be maintained. Specifically, the predetermined density is preferably 10 １９ ・m ３ In this way, it is sufficient if it is possible to form a high-density plasma region 35 that is denser than the density that can sustain a nuclear fusion reaction. The plasma generation unit 30 of the mirror-type fusion device of the present invention can be any known or future device that can rapidly form a plasmoid, which is a high-density plasma region 35, within the confining magnetic field 22.

[0027] In the illustrated example, the plasma generation unit 30 is shown to be composed of at least a pair of magnetized plasmoid generators 31, 31 arranged opposite each other across the longitudinal direction of the central vessel 10. The pair of magnetized plasmoid generators 31, 31 is configured to simultaneously inject plasmoids into the central vessel 10 with momentum sufficient to at least penetrate the confining magnetic field 22. The injected plasmoids collide within the confining magnetic field 22, canceling out their momentum and merging, thereby forming a high-speed, high-density plasma region 35. In this case, injecting plasmoids with momentum sufficient to at least penetrate the confining magnetic field 22 means injecting them into the central vessel 10 with a pressure higher than the magnetic pressure of the confining magnetic field 22.

[0028] A specific example of the magnetized plasmoid generation device 31 used in the plasma generation unit 30 may be, for example, a field-reversed configuration plasma generation device. A field-reversed configuration plasma generation device is capable of generating field-reversed configuration (FRC) plasma. When an FRC plasma generation device is used, FRC plasma is accelerated and plasmoids collide with each other across the confining magnetic field 22. When plasmoids injected with the same momentum collide within the confining magnetic field 22, their momentum is canceled out on the spot, resulting in the formation of a high-speed density gradient. The high-density plasma region 35 thus formed is confined within the confining magnetic field 22 generated by the confining magnetic field configuration generation unit 20. Because the internal current of FRC plasma is composed solely of diamagnetic (Diamagnetic) current, the FRC plasma generation device forms a density gradient within the confining magnetic field 22 sufficiently faster than the magnetic field diffusion time and the growth time of MHD instability, resulting in the self-organization of the high-density plasma region 35 by the diamagnetic current. That is, a high-speed, high-density plasma region 35 is formed by accelerating the FRC plasma and causing it to collide within the confining magnetic field 22. The formed high-density plasma region 35 is then fixed in the center of the confining magnetic field 22 by the confining magnetic field 22.

[0029] Here, the plasmoid of the FRC plasma generating device is launched at a speed of, for example, 100 km / s or more, preferably 300 km / s or more, and more preferably 500 km / s or more.

[0030] As described above, the mirror-type fusion device of the present invention is capable of forming a high-density plasma region quickly within the confining magnetic field, and therefore is able to stably confine high-density plasma.

[0031] In the illustrated example, the magnetized plasmoid generators 31, 31 are connected perpendicular to the center of the central vessel 10, but the present invention is not limited to this. As long as the injected plasmoids are configured to collide with each other within the confinement magnetic field 22, they do not necessarily need to be connected perpendicular to the central vessel 10 and may be connected at an angle. Furthermore, the magnetized plasmoid generators 31, 31 may be connected slightly offset to the left or right rather than at the center of the central vessel 10. For example, when measuring instruments or the like are disposed around the center of the central vessel 10, the magnetized plasmoid generators 31, 31 may be disposed facing each other, offset to the left or right as appropriate, or at an angle. Furthermore, the collision position between the plasmoids is preferably the center of the confinement magnetic field 22, but may be slightly offset up, down, left, or right from the center. Even if the collision position is offset from the center, this does not pose a problem because the high-density plasma region 35 that is formed is moved to the center and fixed there by the confinement magnetic field 22.

[0032] Here, a magnetic field application unit may be provided that controls the confining magnetic field 22 generated by the confining magnetic configuration generation unit 20 to weaken when the magnetized plasmoid generators 31, 31 inject plasmoids into the central vessel 10. The magnetic field application unit applies a magnetic field in a direction that weakens the confining magnetic field 22 when the magnetized plasmoid generators 31, 31 simultaneously inject plasmoids. Specifically, for example, the magnetic field application unit may be a coil that is arranged coaxially with the coil 21 of the confining magnetic configuration generation unit 20 and that passes a current in the opposite direction to that of the coil 21. For example, the magnetic field application unit may apply a magnetic field in a pulsed manner in a direction that weakens the confining magnetic field 22 in synchronization with the injection timing of the plasmoid. This allows the magnetized plasmoid generators 31, 31 to weaken the momentum required for injecting the plasmoid, thereby reducing the output of the magnetized plasmoid generators 31, 31. Note that if the confinement magnetic field configuration generation unit 20 itself is controlled to weaken the confinement magnetic field 22, the response will be poor. However, if a magnetic field application unit that applies a magnetic field in a direction that weakens the confinement magnetic field 22 is used, it will be possible to weaken the confinement magnetic field 22 with good response.

[0033] In the example shown in Fig. 1, a pair of magnetized plasmoid generators 31, 31 is used as the plasma generation unit 30. However, the present invention is not limited to this, and multiple pairs may be used. Fig. 2 is a schematic front cross-sectional view for explaining another example of a mirror-type nuclear fusion device of the present invention. In the figure, parts with the same reference numerals as in Fig. 1 represent the same parts.

[0034] As shown in FIG. 2 , the pair of magnetized plasmoid generators 31, 31 used as the plasma generation unit 30 of the mirror-type fusion device of the present invention may consist of multiple pairs (31a, 31a and 31b, 31b). Each pair is configured to inject plasmoids intermittently in turn. That is, first, plasmoids are simultaneously injected into the central vessel 10 from the pair of magnetized plasmoid generators 31a, 31a, and collide within the confinement magnetic field 22 to form a high-density plasma region 35 at high speed. Next, plasmoids are similarly simultaneously injected from another pair of magnetized plasmoid generators 31b, 31b, and collide to form a high-density plasma region 35 at high speed. By using multiple pairs in this way, when additional plasmoids are injected, they can be injected into the confinement magnetic field 22 faster than the shortest continuous injection time of the magnetized plasmoid generators. This configuration makes it possible to maintain the high-density plasma region 35 for a long period of time. Although the example shown in FIG. 2 uses two pairs, the present invention is not limited to this, and more pairs may be used.

[0035] In the illustrated example, the magnetized plasmoid generators 31, 31 are used as the plasma generation unit 30, and a magnetic field reversed configuration plasma generator is used as a specific example of the magnetized plasmoid generator. However, the present invention is not limited to this. The magnetized plasmoid generators 31, 31 may be, for example, reversed field theta-pinch devices. The reversed field theta-pinch devices are capable of forming spheromak-like plasma. Even when reversed field theta-pinch devices are used as the magnetized plasmoid generators 31, 31, it is sufficient to simultaneously inject spheromak-like plasma across the longitudinal direction of the central vessel 10 with enough momentum to penetrate into the confining magnetic field 22 and cause it to collide within the confining magnetic field 22. The momentum of the colliding spheromak-like plasmas cancels out and coalesces, forming a high-speed density gradient and forming a high-density plasma region 35. In this way, in the mirror-type fusion device of the present invention, a reversed-field theta-pinch device may be used as the plasma generation unit 30 to rapidly form a high-density plasma region 35 within the confinement magnetic field 22 .

[0036] Next, a more specific overall configuration of the mirror-type fusion device of the present invention will be described. FIG. 3 is a schematic side cross-sectional view illustrating the specific overall configuration of the mirror-type fusion device of the present invention. In the figure, parts with the same reference numerals as in FIG. 1 represent the same components. The example shown in FIG. 1 shows the basic form of a so-called mirror-type fusion device, while the example shown in FIG. 3 is an example of a so-called tandem mirror-type fusion device. Furthermore, the plasma generation unit 30 uses a pair of field-reversed configuration plasma generation devices. However, the present invention is not limited to this, and a reversed-field theta-pinch device may also be used, as described above. Furthermore, as shown in FIG. 2, a pair of magnetized plasmoid generation devices may be configured with multiple pairs.

[0037] As shown in the figure, the mirror-type fusion device of the present invention in this example has a repelling section 50. Use of the repelling section 50 makes it a tandem mirror-type fusion device. The repelling section 50 is used to confine fusion-product particles that escape in the longitudinal direction of the central vessel 10 along the magnetic field lines of the confinement magnetic field 22. The repelling section 50 also functions to stabilize the confined plasma. As shown in the example, the repelling section 50 may be provided at both ends of the central vessel 10 in the longitudinal direction. The repelling section 50 may be, for example, as shown in the figure, composed of an anchor section 51 and a thermal barrier section 52. The anchor section 51 suppresses the growth of MHD instability. The thermal barrier section 52 is a thermal barrier. Alternatively, a potential barrier section or a plug section may be provided as the repelling section 50. The potential barrier section provides a barrier based on electric potential. The plug section is a barrier based on electric potential. The repelling section 50 may be composed of one or a combination of these. In the mirror-type fusion device of the present invention, the plasma generation unit 30 is not disposed on the longitudinal axis of the central vessel 10, but is disposed perpendicular to the longitudinal direction of the central vessel 10, so that such a bounce unit 50 can be easily disposed at both ends in the longitudinal direction without any restrictions. In other words, the plasma generation unit 30 can be disposed near the confining magnetic field 22 without being affected by the bounce unit 50, and a high-density plasma region 35 can be formed in the confining magnetic field 22 at high speed, making plasma control easy.

[0038] Furthermore, end sections 60 may be provided further outside the rebound section 50. The end sections 60 are intended to extract energy from fusion-produced particles escaping in the longitudinal direction of the central vessel 10 along the magnetic field lines of the confinement magnetic field 22. In the mirror-type fusion device of the present invention, the plasma generation section 30 is not disposed on the longitudinal axis of the central vessel 10 but is disposed perpendicular to the longitudinal direction of the central vessel 10, making it possible to provide end sections 60 at both longitudinal ends. Therefore, it is possible to configure the device so that energy is extracted directly from the fusion-produced particles using the end sections 60 without being affected by the plasma generation section 30. Note that in the devices described in Patent Documents 2 and 3, it was necessary to dispose the plasma generation section on the longitudinal axis, making it difficult to provide end sections at both longitudinal ends.

[0039] Furthermore, as shown in FIG. 3 , the mirror-type fusion device of the present invention may be provided with a neutral particle beam injector 40. The neutral particle beam injector 40 injects a neutral particle beam into the central chamber to heat the plasma region 35 in the confining magnetic field 22 and induce a fusion reaction. That is, the neutral particle beam injector 40 heats the formed plasma region 35 and induces a neutral particle beam-driven fusion reaction. Even if the plasmoid formed by the plasma generation unit 30 does not have an FRC configuration, for example, the neutral particle beam injector 40 can be used to raise the temperature of the plasmoid and maintain the plasma region 35. Note that the mirror-type fusion device of the present invention is not particularly limited to a neutral particle beam injector, and may be, for example, a radio-frequency heating device as long as it can heat the plasma region in the confining magnetic field.

[0040] In the mirror-type fusion device of the present invention, the high-density plasma region 35 is fixed in the central portion of the confinement magnetic field 22. Therefore, when the neutral particle beam is injected into the plasmoid by the neutral particle beam injection device 40, the neutral particle beam can always be directed toward the center of the plasma region 35, resulting in good beam efficiency.

[0041] In the illustrated example described above, a pair of magnetized plasmoid generators 31, 31 are used as the plasma generation unit 30, facing each other and perpendicular to the longitudinal direction of the central vessel 10. The plasmoids are simultaneously launched into the central vessel with momentum sufficient to at least penetrate the confinement magnetic field 22, and then collide within the confinement magnetic field 22, canceling out the momentum and merging to form a high-speed, high-density plasma region 35. However, the mirror-type fusion device of the present invention is not limited to this. Figure 4 is a schematic side cross-sectional view illustrating another example of a mirror-type fusion device of the present invention. In the figure, parts with the same reference numerals as in Figure 1 represent the same components.

[0042] As shown in Figure 4, the plasma generation section 30 of the mirror-type fusion device of the present invention consists of a laser ablation device 32. The laser ablation device 32 is connected to the central vessel 10 between the two coils 21, 21 of the confinement magnetic field configuration generation section 20. In other words, the laser ablation device 32 is connected to the outer periphery of the central vessel 10, perpendicular to the longitudinal direction of the central vessel 10. The laser ablation device 32 irradiates a target 33 placed inside the central vessel 10 with laser light, and quickly forms a high-density plasma region 35 of laser ablation plasma within the confinement magnetic field 22.

[0043] Even in the case of laser ablation plasma, similarly to the above, forming the plasma region 35 at high speed means forming the plasma region 35 in a predetermined time that is shorter than at least the diffusion time of the magnetic field or the growth time of MHD instability. This predetermined time depends not only on the temperature and density of the plasma but also on the geometric size of the central vessel 10. In one example from a demonstration experiment, the predetermined time was preferably several tens of microseconds, and more preferably about 10 microseconds. In this way, even with the laser ablation device 32, it is sufficient if the plasma region 35 can be formed faster than the diffusion time of the magnetic field or the growth time of MHD instability. Similarly, the high-density plasma region 35 means a plasma region 35 with a predetermined density that is equal to or greater than the density at which a nuclear fusion reaction can be maintained. Specifically, the predetermined density is preferably 10 １９ ・m ３In this way, it is sufficient that the laser ablation device 32 can form a plasma region 35 with a density equal to or higher than that at which a nuclear fusion reaction can be maintained.

[0044] When the target 33 placed in the central vessel 10 reaches the center of the confining magnetic field 22, the target 33 is irradiated with laser light using the laser ablation device 32. The material of the target 33 may be a metal, an insulator, an oxide, or the like, which is heated and converted into plasma by laser irradiation. In this way, the mirror-type fusion device of the present invention may be configured to form a density gradient in the confining magnetic field 22 sufficiently faster than the magnetic field diffusion time or the growth time of MHD instability by using the laser ablation device 32 and the target 33.

[0045] The mirror-type fusion device of the present invention makes it possible to rapidly generate a high-density plasma region within the confinement magnetic field. The generated high-density plasma region can be ignited as thermal plasma, but it is also possible to maintain a high-energy beam with a high fusion reaction cross section for a long time in a relatively hot plasma. In this respect, it is also advantageous to confine the high-density plasma region with the mirrors of the low-magnetic-field confinement magnetic configuration generator.

[0046] Furthermore, the mirror-type nuclear fusion device of the present invention may be configured to capture high-energy ion particles by a confining magnetic field and form a plasma core that is the target of the reaction as FRC plasma.

[0047] Next, we will explain the experimental results of forming FRC plasma using a mirror-type fusion device of the present invention. Figure 5 shows the distribution of FRC plasma formed by the mirror-type fusion device of the present invention over time. The contour map in Figure 5(a) shows the time change in the distribution of the radius of the formed FRC plasma along the mirror magnetic field axis (the longitudinal direction of the central vessel 10), and the graph in Figure 5(b) shows the time change in the radius of the formed FRC plasma at the central cross section. Note that the configuration of the mirror-type fusion device of the present invention that formed the FRC plasma shown in Figure 5 is a pair of magnetized plasmoid generators 31, 31 as shown in Figure 1, arranged opposite each other across the longitudinal direction of the central vessel 10. Here, the vertical axis in Figure 5(a) represents the distance from the central axis X of the central vessel 10 in the longitudinal direction. As shown in Figure 5(a), with the mirror-type fusion device of the present invention, an FRC plasma is formed in a short time with magnetic field lines oriented not in the direction of the incident axis of the injected plasmoid but in the longitudinal direction of the central vessel 10, which is perpendicular to the axial direction, and a high-density plasma region is stably maintained.

[0048] The mirror-type nuclear fusion device of the present invention is not limited to the above-mentioned illustrated example, and it goes without saying that various modifications can be made within the scope of the gist of the present invention.

[0049] REFERENCE SIGNS LIST 10 Central vessel 20 Confinement magnetic field configuration generation section 21 Coil 22 Confinement magnetic field 30 Plasma generation section 31 Magnetized plasmoid generation device 32 Laser ablation device 33 Target 35 Plasma region 40 Neutral particle beam injection device 50 Bounce section 51 Anchor section 52 Thermal barrier section 60 End section

Claims

1. A mirror-type fusion device that confines plasma by a magnetic field, the mirror-type fusion device comprising: A central container extending in the longitudinal direction for confining plasma; A confinement magnetic field coordination generation unit composed of at least two coils arranged coaxially with the longitudinal axis of the central container, the confinement magnetic field coordination generation unit generating a confinement magnetic field for confining plasma between the two coils; A plasma generation unit connected to the central container between the two coils of the confinement magnetic field coordination generation unit, and forming a plasma region of a predetermined density equal to or higher than the density at which a fusion reaction can be maintained within the confinement magnetic field in a predetermined time shorter than at least the diffusion time of the magnetic field or the growth time of MHD instability. A mirror-type fusion device characterized by comprising the above.

2. In the mirror-type fusion device according to claim 1, the plasma generation unit comprises at least a pair of magnetized plasmoid generation devices arranged to face each other across the longitudinal direction of the central container, The pair of magnetized plasmoid generation devices each inject a plasmoid into the central container simultaneously with a momentum such that they can at least penetrate into the confinement magnetic field, and collide within the confinement magnetic field to cancel out the momentum and combine to form a plasma region. A mirror-type fusion device characterized by the above.

3. In the mirror-type fusion device according to claim 2, the pair of magnetized plasmoid generation devices consists of a plurality of pairs, and each pair intermittently injects a plasmoid in order. A mirror-type fusion device characterized by the above.

4. A mirror-type fusion device according to claim 2, further comprising a magnetic field application unit for applying a magnetic field in a direction to weaken the confinement magnetic field when the pair of magnetized plasmoid generation devices inject plasmoids simultaneously. A mirror-type fusion device characterized by the above.

5. In the mirror-type fusion device according to any one of claims 2 to 4, the plasma generation unit is a magnetic field reversal coordination plasma generation device or a reversed magnetic field theta pinch device. A mirror-type fusion device characterized by the above.

6. In the mirror-type fusion device according to claim 1, the plasma generation unit is a laser ablation device that irradiates a target introduced into the central container with laser light to form a plasma region of laser ablation plasma within the confinement magnetic field. A mirror-type fusion device characterized by the above.

7. The mirror-type fusion device according to claim 1, further comprising a neutral particle beam injection device for injecting a neutral particle beam into a central container for heating a plasma region in a confinement magnetic field and for a fusion reaction, or a high-frequency heating device for heating a plasma region in a confinement magnetic field. The mirror-type fusion device is characterized by this.

8. The mirror-type fusion device according to claim 1, further comprising a rebounding portion for confining fusion-generated particles that escape in the longitudinal direction of the central container along the magnetic field lines of the confinement magnetic field. The mirror-type fusion device is characterized by this.

9. The mirror-type fusion device according to claim 1, further comprising an end portion for extracting energy from fusion-generated particles that escape in the longitudinal direction of the central container along the magnetic field lines of the confinement magnetic field. The mirror-type fusion device is characterized by this.

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