Laser resonance driven pellet injection system

Abstract

The invention belongs to the technical field of nuclear fusion control, and specifically relates to a laser resonance driven projectile injection system. The laser resonance driven projectile injection system comprises a vacuum chamber, a focusing lens and the laser resonance driven projectile injection system arranged in the vacuum chamber. The laser resonance driven projectile injection system comprises a focusing lens 1, a parabolic mirror, a plane mirror and a projectile. The focusing lens is arranged outside the vacuum chamber and is used for converging a laser beam so that the focus of the laser beam falls on the projectile. The system has high laser energy utilization efficiency, fast projectile speed, adjustable projectile speed and high purity of injected impurities.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear fusion control, and in particular relates to a laser resonance driven projectile injection system. Background Art

[0002] In controlled nuclear fusion research, injecting impurities into plasma can induce a variety of plasma phenomena, based on which various aspects of plasma behavior can be studied.

[0003] For example, research on impurity transport, ion transport, heat transport, rupture mitigation, ELMy mitigation, charging, and vessel wall treatment.

[0004] There are currently many methods for injecting impurities into plasma, including laser blowing, injection of impurity gas, and impurity projectiles driven by high-pressure gas.

[0005] Each of these methods has its own advantages. The first two methods can inject multiple gaseous impurity pulses into the plasma, while the third method can inject solid impurities. Since this method uses high-pressure gas drive, it is inevitable that the driving gas will enter the plasma while injecting the impurity pellets, which means that the purity of the injected impurities is not high. Summary of the invention

[0006] The purpose of the present invention is to provide a laser resonance driven pellet injection system, namely laser resonance drive, to overcome the disadvantage of low purity of impurities injected by high pressure gas drive. The present invention adopts the laser resonance drive pellet method, which has the characteristics of high laser energy utilization efficiency, fast pellet speed, adjustable speed, and high purity of injected impurities.

[0007] The technical solution of the present invention is as follows:

[0008] The laser resonance driven projectile injection system comprises a vacuum chamber, a focusing lens and the laser resonance driven projectile injection system arranged in the vacuum chamber, wherein the laser resonance driven projectile injection system comprises a focusing lens 1, a parabolic mirror, a plane mirror and a projectile; the focusing lens is arranged outside the vacuum chamber and is used to converge a laser beam so that the focus of the laser beam falls on the projectile;

[0009] There is a light hole in the center of the parabolic lens, which is the passage for incident light;

[0010] There is a firing hole in the center of the plane mirror, which serves as a support for placing the projectile and a barrel for firing the projectile;

[0011] The optical axes of the focusing lens, the parabola and the plane mirror are on the same straight line; the focal points of the focusing lens and the parabola are both located at the position where the emitting hole of the plane mirror is flush with the reflecting surface; the projectile is placed in the emitting hole of the plane mirror, and its end is flush with the reflecting surface of the plane mirror.

[0012] A laser resonance driven projectile injection system, wherein the vacuum chamber comprises a laser window, an observation window, a cavity cover, a cover handle, a vacuum cavity, a device interface flange, and an exhaust interface;

[0013] The vacuum chamber is a square hollow structure with a cavity cover and a cover handle on the upper part, a laser window on the left side, a device interface flange on the right side, and an exhaust interface on the lower part.

[0014] A laser resonance driven projectile injection system has a laser resonance cavity arranged inside a vacuum chamber near a laser port and an observation window. The laser resonance cavity is installed in the vacuum chamber and is composed of a parabolic mirror, a plane mirror and a projectile. The laser is repeatedly reflected between the three, which plays a role of repeatedly providing kinetic energy to the projectile, thereby achieving the purpose of driving the projectile.

[0015] A laser resonance driven projectile injection system is provided with an XY displacement stage in a vacuum chamber, a Z displacement stage is provided on the XY displacement stage, a parabolic mirror and an angular mirror frame are placed on the Z displacement stage, and the angular mirror frame is used for horizontal rotation and pitch adjustment of the parabolic mirror.

[0016] A laser resonance driven projectile injection system, wherein the laser beam is converged by a focusing lens to become a convergent beam, and after the convergent beam passes through the light hole of the parabolic lens, its focus falls on the end face of the projectile;

[0017] A laser resonance driven projectile injection system, in which the laser interacts with the projectile, and its energy is mainly divided into two parts, a small part is absorbed by the projectile, and most of it is reflected by the projectile.

[0018] A laser resonance driven projectile injection system, the laser energy absorbed by the projectile causes part of the projectile material to be melted, thereby generating high temperature and high pressure gas or plasma, which is ejected in the direction opposite to the incident light direction, and the projectile is made to obtain a certain speed by using the principle of recoil motion, and moves in the direction of the incident light; the laser beam is reflected by the projectile and incident on the parabolic mirror, and is reflected again by the parabolic mirror. Since these lights pass through the focus of the parabolic mirror, they must be parallel to the main optical axis of the parabolic mirror after reflection; these lights are incident vertically on the plane mirror, and must be reflected vertically, and then incident on the parabolic mirror again in parallel; finally, these lights will be converged to the focus, that is, the projectile, by the parabolic mirror. After these lasers are reflected again on the projectile, the above process will be repeated, repeatedly bombarding the projectile, thereby forming the laser resonance drive on the projectile.

[0019] The beneficial effects of the present invention are:

[0020] The laser energy utilization efficiency is high, the projectile speed is fast, the projectile speed is adjustable, and the purity of the injected impurities is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 : Schematic diagram of the laser resonance driven projectile injection system.

[0022] Figure 2 , structure diagram of laser resonance driven projectile injection system.

[0023] In the figure: 1-focusing lens; 2-parabolic mirror; 3-plane mirror; 4-projectile; 5-oscillating light; 6-incident light after focusing; 7-laser window; 8-observation window; 9-cavity cover; 10-cover handle; 11-vacuum chamber cavity; 12-device interface flange; 13-angle mirror holder; 14-XY displacement stage; 15-Z lifting platform; 16-exhaust interface. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Combine the following Figure 1 Explain the working principle of the laser resonance driven projectile injection system.

[0026] The laser resonance cavity is the core of the laser resonance driven projectile injection system, which includes a focusing lens 1, a parabolic mirror 2, a plane mirror 3 and a projectile 4;

[0027] There is a light hole in the center of the parabola 2, which is the passage for incident light;

[0028] There is a launching hole in the center of the plane mirror 3, which serves as a support for placing the projectile and a barrel for launching the projectile;

[0029] The optical axes of the focusing lens 1, the parabola 2 and the plane mirror 3 are on the same straight line; the focal points of the focusing lens 1 and the parabola 2 are both located at the position where the emitting hole of the plane mirror is flush with the reflecting surface; the projectile 4 is placed in the emitting hole of the plane mirror, and its end is flush with the reflecting surface of the plane mirror.

[0030] like Figure 1As shown in the figure: the laser beam is converged by the focusing lens 1 to become a convergent beam 6. After the convergent beam 6 passes through the light hole of the parabola 2, its focus falls on the end face of the projectile 4. The laser interacts with the projectile, and its energy is mainly divided into two parts: a small part is absorbed by the projectile 4, and most of it is reflected by the projectile 4. The laser energy absorbed by the projectile 4 causes part of the projectile material to be ablated, thereby generating high-temperature and high-pressure gas or plasma, which is ejected in the direction opposite to the direction of the incident light. The principle of recoil motion is used to make the projectile gain a certain speed and move in the direction of the incident light. After being reflected by the projectile 4, the laser beam is incident on the parabola and reflected again by the parabola. Since these lights pass through the focus of the parabola 2, they must be parallel to the main optical axis of the parabola 2 after reflection; these light rays are vertically incident on the plane mirror 3, and must be vertically reflected, and then are parallelly incident on the parabola 2 again; finally, these lights will be converged to the focus, that is, the projectile 4, by the parabola 2. After these lasers are reflected again on the projectile 4, the above process will be repeated to bombard the projectile 4 repeatedly, thereby forming a resonant drive of the laser on the projectile 4.

[0031] Combine the following Figure 2 Describe the structure of the laser resonance driven projectile injection system and the functions of its various parts. Figure 2 Shown is a cross-sectional view of the system structure.

[0032] The focusing lens 1 is installed outside the vacuum chamber and is used to converge the laser beam so that the focus of the laser beam falls on the projectile 4.

[0033] The vacuum chamber includes: a laser window 7, an observation window 8, a cavity cover 9, a cover handle 10, a vacuum cavity 11, a device interface flange 12, and an exhaust interface 16.

[0034] The vacuum chamber is a square hollow structure, with a cavity cover plate 9 and a cover plate handle 10 on the upper part, a laser window 7 on the left side, a device interface flange 12 on the right side, and a vacuum interface 16 on the lower part;

[0035] A laser resonance cavity is arranged inside the vacuum chamber near the laser port 7 and the observation window 8. The laser resonance cavity is installed in the vacuum chamber and is composed of a parabolic mirror 2, a plane mirror 3 and a projectile 4. The laser is repeatedly reflected between the three, which plays a role of repeatedly providing kinetic energy to the projectile 4, thereby achieving the purpose of driving the projectile 4.

[0036] A Z-direction translation stage 15 is arranged on the XY-direction translation stage 14, on which the parabolic mirror 2 and the angle mirror frame 13 are placed, and the angle mirror frame 13 is used for horizontal rotation and pitch adjustment of the parabolic mirror. The translation stage XY direction 14 and the lifting platform Z direction 15 are used to adjust the position of the parabolic mirror.

[0037] The vacuum chamber is mainly used to install the laser resonance cavity, provide and maintain the high vacuum environment for the laser resonance cavity to work, and provide a flange for connecting the vacuum chamber of the main device and the exhaust unit, and provide a channel for the incident light and the projectile 4.

[0038] Combine the following Figure 2 Describe the installation steps of the laser resonance driven pellet injection system.

[0039] Step 1: Install the vacuum chamber 11 on the bracket;

[0040] Step 2: Connect the device interface flange 12 on the vacuum chamber 11 to the main device vacuum chamber;

[0041] Step 3: Install the plane mirror 3 in the vacuum chamber cavity 11 so that the small hole in the center of the plane mirror 3 is aligned with the plasma;

[0042] Step 4: Adjust the incident laser beam so that its spot is located at the center of the plane mirror 3 and is perpendicular to the emitting surface;

[0043] Step 5: Mount the focusing lens 1 on an optical bracket outside the vacuum chamber 11 so that the focal point of the laser beam after convergence is located at the position of the central emission hole of the plane mirror 3;

[0044] Step 6: Press the angle mirror frame 13, the translation stage XY direction 14, and the lifting platform Z direction 15 Figure 2 The position shown is installed in the vacuum chamber 11;

[0045] Step 7: Install the parabola 2 on the angle mirror frame 13, adjust the angle mirror frame 13, the translation stage XY direction 14, and the lifting platform Z direction 15, so that the reflected light of the plane mirror 3 is reflected by the parabola 2 and then vertically incident on the plane mirror 3.

[0046] Step 8: Cover the cavity cover plate 9 to seal the vacuum chamber cavity 11;

[0047] Step 9: Connect the vacuum unit via the vacuum interface 16.

[0048] like Figure 1As shown, the core of the present invention is a laser resonant cavity, which is mainly composed of a parabola 2 and a plane mirror 3. The main optical axis of the parabola is perpendicular to the reflection surface of the plane mirror, and its focus is located on the reflection surface of the plane mirror. In the above structure, if a converging light beam with a focus on the plane mirror is incident on the plane mirror, it will be reflected by the plane mirror and become a light beam passing through the focus of the parabola; this light beam is incident on the parabola and reflected, and becomes a light beam parallel to the main optical axis of the parabola; this light beam is incident on the plane mirror again vertically and will be reflected vertically to the mirror surface, and after reflection, it will be incident on the parabola parallel to the main optical axis; after reflection by the parabola, it becomes a converging light beam with a focus on the plane mirror. The subsequent reflection of this light beam will repeat the above process. If the reflection loss and aberration of the light are not considered, the above process will continue. If a target pellet is placed at the above focal position, the target pellet will be repeatedly bombarded by the light beam and the projectile will be launched.

[0049] The above physical process is the theoretical basis of the present invention. The technical solution of the present invention is described in detail below based on the above process.

[0050] like Figure 1 As shown in the figure, when the incident laser beam converges along the optical axis through the focusing lens 1 and passes through the light hole of the parabola 2, its focus falls exactly on the projectile 4. After the laser interacts with the projectile, its energy is mainly divided into two parts: a small amount of energy is absorbed by the projectile, and most of the energy is reflected. The laser energy absorbed by the projectile causes part of the projectile material to melt to produce high-temperature and high-pressure gas and plasma. These gases and plasma are ejected in the opposite direction of the incident light, and the principle of recoil motion is used to make the projectile gain a certain speed and move in the direction of the incident light. This process is similar to the principle of rocket launch. Most of the laser energy is reflected by the projectile. These reflected lights are incident on the parabola 2 from the position at the focus of the parabola 2, and are emitted parallel to the main optical axis of the parabola 2 after reflection, and then are incident on the plane mirror 3 vertically, and then are reflected by the plane mirror 3 and are incident on the parabola (2) parallel to the main optical axis of the parabola 2, and then are reflected by the parabola (2) and converged to the focus of the parabola (2) again. Since the projectile (4) is located exactly at the focus of the parabola (2), the laser reflected by the projectile will repeatedly bombard the projectile, forming a repeated drive of the laser on the projectile. Since the speed of light is much greater than the movement speed of the projectile, the above-mentioned resonance drive process will be repeated many times until the projectile is launched, and the process will not stop. The above is the principle of laser resonance drive of the projectile.

[0051] The following is an estimate of the projectile launch speed. Assume that the area of ​​the parabolic reflective surface is S1, the area of ​​the light hole on the parabolic mirror is s2, the reflectivity of the parabolic mirror and the plane mirror is R1, the reflectivity of the projectile to the laser is R2, the efficiency of converting the laser energy absorbed by the projectile into the kinetic energy of the projectile is α, and the laser incident energy is E. The laser in the laser resonant cavity completes a resonant reflection and then is incident on the projectile again. It needs to go through a reflection process of the projectile, two parabolic mirrors, and one plane mirror. The reflection efficiency of these four reflections is If the mass of the projectile is m, then the velocity of the projectile can be estimated using the following formula:

[0052]

[0053] If the resonant cavity is not used, the focused laser will be directly incident on the projectile, and the reflected light will have no effect on driving the projectile. At this time, the speed of the projectile is Since the resonant laser round trip time is much shorter than the projectile acceleration time, the number of reflections n tends to infinity, and the factor If R1, R2, s1 / (s1+s2) take the typical value of 99%, β = 95%, the energy utilization after using the laser resonant cavity is increased by 20 times compared with direct laser injection. If there is a reference α value, the projectile velocity can be further estimated. For example, α = 1%, E = 1J, m = 0.1mg, Obviously, the use of laser resonant cavity can make full use of the energy of reflected light, greatly improving the efficiency of energy utilization. This laser resonant projectile driving method makes full use of the energy of reflected light, so that the projectile has a higher launch speed. According to the above formula, the launch speed of the projectile can be adjusted by adjusting the ratio of the energy E of the incident laser beam and the mass m of the projectile.

Claims

1. A laser resonance driven projectile injection system, comprising a vacuum chamber and a laser resonance cavity arranged in the vacuum chamber, wherein the laser resonance cavity comprises a focusing lens (1), a parabolic mirror (2), a plane mirror (3) and a projectile (4); the focusing lens (1) is installed outside the vacuum chamber and is used to converge a laser beam so that the focus of the laser beam falls on the projectile (4); Features: The parabola (2) has a light hole at its center, which is a passage for incident light. The plane mirror (3) has a firing hole in the center, which serves as a support for placing the projectile and a barrel for firing the projectile; The optical axes of the focusing lens (1), the parabolic lens (2) and the plane mirror (3) are on the same straight line; The focal points of the focusing lens (1) and the parabolic mirror (2) are both located at positions where the emitting hole of the plane mirror is flush with the reflecting surface; the projectile (4) is placed in the emitting hole of the plane mirror, and its end is flush with the reflecting surface of the plane mirror.

2. A laser resonance driven pellet injection system as claimed in claim 1, characterized in that: The vacuum chamber comprises a laser window (7), an observation window (8), a cavity cover plate (9), a cover plate handle (10), a vacuum cavity (11), a device interface flange (12), and an exhaust interface (16); The vacuum chamber is a square hollow structure, with a cavity cover plate (9) and a cover plate handle (10) arranged on the upper part, a laser window (7) arranged on the left side, a device interface flange (12) arranged on the right side, and an exhaust interface (16) arranged on the lower part.

3. A laser resonance driven pellet injection system as claimed in claim 2, characterized in that: A laser resonance cavity is arranged inside the vacuum chamber on one side close to the laser window (7) and the observation window (8). The laser resonance cavity is installed in the vacuum chamber and is composed of a parabolic mirror (2), a plane mirror (3) and a projectile (4). Laser light is repeatedly reflected between the three, which plays a role in repeatedly providing kinetic energy to the projectile (4), thereby achieving the purpose of driving the projectile (4).

4. A laser resonance driven pellet injection system as claimed in claim 2, characterized in that: An XY displacement stage (14) is also arranged inside the vacuum chamber, a Z displacement stage (15) is arranged on the XY displacement stage (14), a parabolic mirror (2) and an angular mirror frame (13) are placed on the Z displacement stage (15), and the angular mirror frame (13) is used for horizontal rotation and pitch adjustment of the parabolic mirror.

5. A laser resonance driven pellet injection system as claimed in claim 1, characterized in that: The laser beam is converged by a focusing lens (1) to become a convergent light beam (6). After the convergent light beam (6) passes through the light hole of the parabolic lens (2), its focus falls on the end surface of the projectile (4).

6. A laser resonance driven pellet injection system as claimed in claim 1, characterized in that: The laser interacts with the projectile (4), and its energy is mainly divided into two parts, a small part is absorbed by the projectile (4), and most of it is reflected by the projectile (4).

7. A laser resonance driven pellet injection system as claimed in claim 6, characterized in that: The laser energy absorbed by the projectile (4) causes a portion of the projectile material to melt, thereby generating high-temperature and high-pressure gas or plasma, which is ejected in a direction opposite to the direction of the incident light. The projectile acquires a certain speed by utilizing the principle of recoil motion, and moves in the direction of the incident light. The laser beam is reflected by the projectile (4) and then incident on the parabola and is reflected again by the parabola. Since the light passes through the focus of the parabola (2), it must be parallel to the main optical axis of the parabola (2) after reflection. These light rays are incident vertically on the plane mirror (3), and will inevitably be reflected vertically, and then are incident on the parabola (2) again in parallel; finally, these light rays will be focused by the parabola (2) to the focal point, that is, the projectile (4); after these lasers are reflected again on the projectile (4), the above process will be repeated, repeatedly bombarding the projectile (4), thereby forming a resonant drive of the laser on the projectile (4).

Images