A spherical tokamak fuelling system based on supersonic molecular beam injection

Abstract

The application relates to the technical field of nuclear fusion, in particular to a spherical tokamak feeding system based on ultrasonic molecular beam injection. The application relates to the technical field of nuclear fusion, in particular to a spherical tokamak feeding system based on ultrasonic molecular beam injection. The spherical tokamak feeding system comprises a gas tank, a hydrogen tank, a pressure reducing valve, a needle valve and the like to form a common gas feeding loop as an initial feeding channel to meet the feeding demand of daily operation, and an ultrasonic molecular beam injection gas path is additionally arranged as a secondary supplementary feeding channel for a plasma discharge process to improve plasma density. Compared with the traditional gas feeding mode, the secondary feeding has faster response time and higher feeding efficiency. Finally, the ultrasonic molecular beam injection gas path and the initial feeding channel are connected through a gas pressure measuring assembly to monitor the gas pressure of the two gas paths; the gas quantity of each feeding can be accurately measured based on the gas pressure of the two gas paths. The application can realize staged fuel gas injection of the spherical tokamak, greatly improves the fuel gas injection efficiency, and reduces the wall cycle.

Description

Technical Field

[0001] This invention relates to the field of nuclear fusion technology, and in particular to a spherical tokamak feeding system based on ultrasonic molecular beam injection. Background Technology

[0002] Research into controlled thermonuclear fusion stems from humanity's growing energy needs. Since the 20th century, rapid population growth, increased production, and improved living standards have led to the depletion of non-renewable fossil fuels. Fission energy, one of the new energy sources discovered by humankind, has become a relatively mature technology, but the reserves of exploitable fission fuels are limited. Fusion energy, in addition to its abundant fuel reserves, offers several advantages over fossil fuels. Compared to fossil fuels, fusion energy is air-polluting; compared to fission energy, it causes far less radioactive pollution and avoids the risk of large-scale, uncontrolled supercritical energy releases.

[0003] Magnetic confinement fusion based on tokamak devices is one of the most promising pathways to the peaceful use of nuclear fusion energy. To achieve magnetic confinement fusion, the density of the fusion plasma must reach a certain order of magnitude. Currently, the main fueling methods in magnetic confinement fusion devices include gas puffing (GP), supersonic molecular beam injection (SMBI), projectile injection, and compact ring injection. Among them: Conventional fuel injection involves delivering fuel gas into a vacuum chamber via gas diffusion. This is the most basic fueling method, but it is inefficient and cannot precisely control fuel distribution.

[0004] Ultrasonic molecular beam injection uses a Laval nozzle to accelerate high-pressure fuel gas to supersonic speeds (approximately 1 km / s), forming a molecular beam that penetrates a magnetic field. This technology has been applied to more than 10 facilities both domestically and internationally, including EAST and J-TEXT, and can achieve more uniform fuel distribution, but the total amount of fuel injected is limited.

[0005] Projectile injection involves freezing fuel into solid ice projectiles (approximately 1–3 mm in diameter) and injecting them into the plasma core at high speed (approximately 300 m / s). This method can increase the fuel injection depth, but its penetration capability in strong magnetic field devices is limited due to the high-temperature resistance of the projectile material, and its operation and maintenance costs are high.

[0006] The compact ring injection principle involves ionizing fuel gas using pulsed high voltage to form a high-density, self-organized plasma ring. A strong Lorentz force is then used to accelerate the compact ring to ultra-high directional velocities, enabling deep space fuel injection. This novel injection technology boasts advantages such as long lifespan, high density, and high speed; however, the technology is still immature, the system is large and complex, and controlling the repetition frequency and interaction is challenging.

[0007] There are many scenarios requiring refueling in spherical tokamaks. For example, glow discharge cleaning of the vacuum chamber requires a constant flow of hydrogen or helium. During tokamak discharge, a suitable amount of gas needs to be introduced beforehand as plasma fuel, and the refueling gas needs to be replenished promptly during the discharge process to stabilize the plasma density. This is especially true for spherical tokamaks, whose discharge time is relatively short, typically around 100 ms. Existing refueling methods cannot meet the refueling requirements of spherical tokamaks within such a short timeframe. Summary of the Invention

[0008] This invention aims to at least improve one of the technical problems existing in the prior art. To this end, this invention proposes a spherical tokamak feeding system based on ultrasonic molecular beam injection.

[0009] The technical solution of the present invention is as follows: A spherical tokamak feeding system based on ultrasonic molecular beam injection, comprising: Hydrogen cylinder with pressure reducing valve; A needle valve is connected to the pressure reducing valve; The gas cylinder is connected to the needle valve through a first pipe to form a first gas delivery path, and the gas cylinder is connected to the spherical tokamak through a second pipe to form a second gas delivery path, serving as an initial feeding channel; An ultrasonic molecular beam injection device is connected to the spherical tokamak. The ultrasonic molecular beam injection device, which is away from the spherical tokamak, is connected to the needle valve through a third pipe to form an ultrasonic molecular beam injection gas path, which serves as a supplementary feeding channel. A pressure measurement component is connected to the ultrasonic molecular beam injection gas path and the second gas delivery path to monitor the pressure of the two gas paths; The amount of injected gas is measured by the pressure of the two gas paths to accurately increase the plasma density.

[0010] In one possible technical solution, it further includes: The first pressure reducing valve is connected to the needle valve and is used to regulate the gas pressure in the pipeline of the first gas delivery path. The first needle valve has one end connected to the first pressure reducing valve and the other end connected to the gas tank, and is used to regulate airflow and stabilize gas delivery pressure.

[0011] In one possible technical solution, it further includes: The second needle valve is connected to the gas tank; A piezoelectric valve is connected at one end to the second needle valve and at the other end to the spherical tokamak inlet to control the gas supply.

[0012] In one possible technical solution, it further includes: An air bag and a third needle valve are connected in series to a third pipe between the needle valve and the air pressure measuring component; The fourth and fifth needle valves are installed on the third pipes at both ends of the air bag.

[0013] In one possible technical solution, the pressure measurement component further includes: The differential pressure sensor is connected to the fourth needle valve; The sixth needle valve is connected at one end to the differential pressure sensor and at the other end to the second air supply path.

[0014] In one possible technical solution, the ultrasonic molecular beam injection device is further comprising an entire assembly of stainless steel, including: The main body of the device is mounted on a spherical tokamak, and the main body of the device has a hollow cavity; An outer flange is connected to the main body of the device to form a beam source vacuum chamber, and a through hole is provided in the middle of the outer flange; An outer shielding cylinder is installed on one side of the outer flange and located within the hollow cavity; The inner shielding cylinder is embedded inside the outer shielding cylinder. The inner shielding cylinder and the outer shielding cylinder can be used to mitigate the impact of large plasma bursts on the solenoid valve. A Laval nozzle is installed between the outer shielding cylinder and the inner shielding cylinder to generate an ultrasonic molecular beam; A gas delivery pipe, passing through the outer flange and connected to the Laval nozzle, is used to deliver gas, wherein a sealing ring is provided at the connection between the gas delivery pipe and the outer flange to isolate air; A vacuum monitoring port is installed on the side wall of the main body of the device to monitor the vacuum status of the SMBI. An air extraction port is installed on the side wall of the device body away from the vacuum monitoring port and is used to connect a vacuum pump assembly.

[0015] In one possible technical solution, the outer shielding cylinder, the inner shielding cylinder, the Laval nozzle, and the center of the gas delivery pipe are located on the same axis.

[0016] In one possible technical solution, the aperture of the Laval nozzle is further 0.2 mm.

[0017] In one possible technical solution, the ultrasonic molecular beam injection device further includes: A hydrogen-alpha observation window, installed on the outer flange, is used to connect to a hydrogen-alpha signal for diagnosis and to detect the ionization of hydrogen.

[0018] In one possible technical solution, the ultrasonic molecular beam injection device further includes: A valve lead seat, mounted on the outer flange, is used to connect the drive line and control the opening and closing of the solenoid valve.

[0019] The feeding system and ultrasonic molecular beam injection device for the spherical tokamak according to the present invention can perform staged fuel gas injection into the spherical tokamak. Based on the gas pressure measurement component, the gas injection time can be precisely controlled, greatly improving the fuel gas injection efficiency and reducing wall circulation. Specifically, this is reflected in: By using a pressure measurement component to obtain the plasma discharge time in a timely manner, and by rapidly replenishing hydrogen through an ultrasonic molecular beam injection gas path to increase plasma density and improve injection efficiency, this invention combines two feeding methods through gas path modification, effectively meeting the feeding requirements of spherical tokamaks.

[0020] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the gas path control of a spherical tokamak feeding system based on ultrasonic molecular beam injection according to an embodiment of the present invention; Figure 2 This is an overall schematic diagram of the ultrasonic molecular beam injection device according to an embodiment of the present invention; Figure 3 This is a cross-sectional schematic diagram of an ultrasonic molecular beam injection device according to an embodiment of the present invention; Figure 4 yes Figure 2 A side view diagram; Figure 5 The number of particles injected by SMBI is shown under different source pressures and pulse durations; Figure 6 The evolution of key plasma parameters by SMBI fuel injection is shown in 250715027 experiments.

[0023] Figure label: Hydrogen cylinder 1, pressure reducing valve 101; Needle valve 2; Gas tank 3, first pressure reducing valve 301, first needle valve 302, second needle valve 303, piezoelectric valve 304; Ultrasonic molecular beam injection device 4, device body 40, outer flange 41, outer shielding cylinder 42, inner shielding cylinder 43, Laval nozzle 44, gas delivery pipe 45, vacuum monitoring port 46, gas extraction port 47, hydrogen-alpha observation window 48, valve lead seat 49, fourth needle valve 401, fifth needle valve 402. Barometric pressure measurement component 5, differential pressure sensor 501, sixth needle valve 502 Air bag 6, third needle valve 601.

[0024] Vacuum gauge 7; Vacuum pump set 8; Vacuum gauge 9; Spherical tokamak 10. Detailed Implementation

[0025] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0026] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] The terms "first," "second," "third," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects and not to describe a particular order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, it may include a series of steps or units, or optionally, steps or units not listed, or other steps or units inherent to these processes, methods, products, or devices.

[0029] Example 1 like Figure 1 As shown, this embodiment provides a spherical tokamak feeding system based on ultrasonic molecular beam injection, which includes: Hydrogen cylinder 1 has a pressure reducing valve 101. The gas pressure of hydrogen cylinder 1 is 10MPa, but it is not limited to this. At this time, it cannot be directly connected to the initial feeding channel or the ultrasonic molecular beam injection device. The pressure reducing valve 101 is used to reduce the gas pressure released from hydrogen cylinder 1 from 10MPa to about 1MPa. Needle valve 2 is connected to the pressure reducing valve 101 to control the gas switching operation after pressure reduction; Gas tank 3 is connected to needle valve 2 through a first pipe to form a first gas delivery path, and gas tank 3 is connected to spherical tokamak through a second pipe to form a second gas delivery path, serving as an initial feeding channel; The first pressure reducing valve 301 is connected to the needle valve 2 and is used to regulate the pipeline gas pressure of the first gas delivery path, which can reduce the hydrogen pressure from about 1 MPa to about 0.12 MPa. The first needle valve 302 is connected at one end to the first pressure reducing valve 301 and at the other end to the gas tank 3, and is used to regulate the airflow and stabilize the gas delivery pressure.

[0030] The second needle valve 303 is connected to the gas tank 3; The piezoelectric valve 304 is connected at one end to the second needle valve 303 and at the other end to the spherical tokamak inlet to control the gas supply.

[0031] The ultrasonic molecular beam injection device 4 is connected to the spherical tokamak. The ultrasonic molecular beam injection device 4, which is away from the spherical tokamak, is connected to the needle valve 2 through a third pipe to form an ultrasonic molecular beam injection gas path (SMBI gas path) as a supplementary feeding channel. A pressure measurement component 5 is connected to the ultrasonic molecular beam injection gas path and the second gas delivery path to monitor the pressure of the two gas paths. The pressure measurement component 5 includes: Differential pressure sensor 501 is connected to the fourth needle valve 401, wherein the differential pressure sensor has a measurement range of ±2 kPa, an accuracy of 0.2%, and a pressure resistance of 2 MPa; The sixth needle valve 502 is connected at one end to the differential pressure sensor 501 and at the other end to the second air supply path; The amount of injected gas is measured by gas pressure measurement in two gas paths to increase plasma density.

[0032] It should be noted that, in this embodiment, the following is also included: Air bag 6 and third needle valve 601, the air bag 6 and the third needle valve 601 are connected in series to the third pipe between the needle valve 2 and the air pressure measuring component 5; The fourth needle valve 401 and the fifth needle valve 402 are installed on the third pipes at both ends of the air bag 6.

[0033] In this embodiment, the plasma discharge time is obtained in a timely manner through a gas pressure measurement component. The workflow is as follows: First, the fifth needle valve 402 is opened. Then, the gas pressure in the third pipe is adjusted according to experimental needs via the fourth needle valve 401 and the third needle valve 601. Finally, the fifth needle valve 402 is closed. At this time, the pressure difference across the fifth needle valve 402 is 0. When the plasma discharge triggers SMBI gas delivery, the gas on the right side of the fifth needle valve 402, connected to the ultrasonic molecular beam injection device 4, decreases, and the gas pressure drops. The differential pressure sensor 501 promptly detects the pressure difference across the two ends, thereby accurately measuring the amount of injected fuel, greatly improving the fuel gas injection efficiency and reducing wall circulation.

[0034] It should be noted that in this embodiment, the consumed gas can be calculated using PV=nRT. Taking the measurement of SMBI with a differential pressure sensor as an example, the pressure decrease in the pipeline during injection can be measured, and then calculated using the formula ΔPV. pipe =nRT, which can be used to calculate the number of injected molecules.

[0035] Where ΔP (unit: Pa) is the decrease in pressure, V pipe R is the volume of the delivery pipeline, n (unit: mol) is the injection volume, R = 8.314 J / (mol·K), and T (K) is the gas temperature. Figure 5 The figure shows the number of particles injected by SMBI under different source pressures and pulse durations. In the figure, the asterisk (*) symbol represents the measured value, and the solid line is a linear fit obtained from the experimental values. The calibration relationship is N = 1.15Pt + 0.14, which shows that the number of emitted particles is consistently around 10. 19 This is the magnitude.

[0036] Experiments showed that the pressure differential during a single feed on the NCST device was approximately 150 Pa. The pipe length from the fifth needle valve 402 to the SMBI valve was approximately 8.5 m, with an inner diameter of 4 mm and a volume of 1.07E-4 m³. 3 At a temperature of 300K (27℃), substituting into the formula, we can get that the approximate number of particles ejected in one shot is 4E18.

[0037] To verify that the ultrasonic molecular beam injection gas path of this application can rapidly replenish hydrogen to increase plasma density and improve injection efficiency, this embodiment illustrates the evolution of key plasma parameters by SMBI fuel injection in experiment number 250715027 on the NCST device, such as... Figure 6 As shown, where Figure 6 In this context, (a) represents the plasma current. Figure 6 In the diagram, (b) represents the Ha signal. Figure 6 (c) in the text represents the SMBI signal. Figure 6 In this context, (d) represents the electron temperature measured by the Langmuir probe. Figure 6In this context, (e) represents the electron density measured by the Langmuir probe. For example... Figure 6 As shown in (a), when SMBI is injected at 485 ms, the plasma current is in a flat-top phase. After SMB injection, the amplitude of the plasma current (IP) does not change significantly, indicating that SMBI has little effect on IP. Figure 6 As shown in (b), the Hα signal intensity begins to increase within 1 millisecond after SMB injection, indicating that the SMB has reached the plasma boundary and completed ionization. Figure 6 As shown in (c), the duration of the SMBI pulse is 2 milliseconds. Figure 6 (d) The electron temperature measured by the electrostatic probe indicates that the electron temperature drops sharply after SMB injection. Figure 6 The electron density data presented in (e) show that the electron density at 490 ms significantly increased from 1.5 × 10 / m to 2.3 × 10 / m compared to 485 ms. These results demonstrate that the SMBI fuel injection method of this invention exhibits rapid response and significant efficiency enhancement.

[0038] It should be noted that, in this embodiment, to compare the gas delivery effect of the SMBI (Sonic Molecular Beam Injection) gas path with the first gas delivery path, this pressure measuring component 5 can also measure the number of particles ejected by ordinary gas delivery. Simply close the second needle valve 303 and open the sixth needle valve 502. At this time, the first gas delivery path can use the SMBI gas path and the pressure measuring component. The SMBI is also equipped with a vacuum gauge and a pumping system, and a gate valve is installed for isolation from the main vacuum chamber. Closing the gate valve and opening the SMBI valve allows the pumping system to expel air from the pipeline, ensuring the purity of the injected gas.

[0039] Example 2 like Figures 1 to 6 As shown, this embodiment provides an ultrasonic molecular beam injection device, which is applied to the above-mentioned feeding system. The ultrasonic molecular beam injection device 4 is entirely made of stainless steel and includes: The main body 40 is mounted on the spherical tokamak 10, and the main body 40 has a hollow cavity. An outer flange 41 is connected to the main body 40 of the device to form a beam source vacuum chamber, and a through hole is provided in the middle of the outer flange 41; The outer shielding cylinder 42 is installed on one side of the outer flange 41 and located inside the hollow cavity; The inner shielding cylinder 43 is embedded inside the outer shielding cylinder 42. The inner shielding cylinder 43 and the outer shielding cylinder 42 can be used to mitigate the impact of large plasma bursts on the solenoid valve. A Laval nozzle 44 is installed between the outer shielding cylinder 42 and the inner shielding cylinder 43 to generate an ultrasonic molecular beam, wherein the aperture of the Laval nozzle 44 is 0.2 mm. A gas delivery pipe 45 passes through the outer flange 41 and is connected to the Laval nozzle 44 for delivering gas, wherein a sealing ring is provided at the connection between the gas delivery pipe 45 and the outer flange 41 to isolate air. Vacuum monitoring port 46 is installed on the side wall of the main body 40 of the device and is used to connect vacuum gauge 9 to monitor the vacuum status of SMBI; The air extraction port 47 is installed on the side wall of the device body 40 away from the vacuum monitoring port 46, and is used to connect the vacuum pump group 8; A hydrogen-alpha (H-alpha, abbreviated as Ha) observation window 48 is installed on the outer flange 41 and is used to connect to hydrogen-alpha signal diagnostics to detect the ionization of hydrogen. The valve lead seat 49 is installed on the outer flange 41 and is used to connect the drive line to control the opening and closing of the solenoid valve.

[0040] It should be noted that, in this embodiment, the centers of the outer shielding cylinder 42, the inner shielding cylinder 43, the Laval nozzle 44, and the gas delivery pipe 45 are located on the same axis.

[0041] The feeding system and ultrasonic molecular beam injection device for the spherical tokamak according to the present invention can perform staged fuel gas injection into the spherical tokamak. Based on the gas pressure measurement component, the gas injection time can be precisely controlled, greatly improving the fuel gas injection efficiency and reducing wall circulation. Specifically, this is reflected in: By using a pressure measurement component to obtain the plasma discharge time in a timely manner, and by rapidly replenishing hydrogen through an ultrasonic molecular beam injection gas path to increase plasma density and improve injection efficiency, this invention combines two feeding methods through gas path modification, effectively meeting the feeding requirements of spherical tokamaks.

[0042] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0043] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0044] Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The reference to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily indicate the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0045] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A spherical tokamak feeding system based on ultrasonic molecular beam injection, characterized in that, include: Hydrogen cylinder (1) with pressure reducing valve (101); The needle valve (2) is connected to the pressure reducing valve (101); The gas tank (3) is connected to the needle valve (2) through a first pipe to form a first gas delivery path, and the gas tank (3) is connected to the spherical tokamak through a second pipe to form a second gas delivery path, serving as an initial feeding channel; An ultrasonic molecular beam injection device (4) is connected to the spherical tokamak. The ultrasonic molecular beam injection device (4) located away from the spherical tokamak is connected to the needle valve (2) through a third pipe to form an ultrasonic molecular beam injection gas path as a supplementary feeding channel. The ultrasonic molecular beam injection device (4) includes: The device body (40) is mounted on a spherical tokamak, and the device body (40) has a hollow cavity; An outer flange (41) is connected to the main body (40) of the device, and a through hole is provided in the middle of the outer flange (41); An outer shielding cylinder (42) is installed on one side of the outer flange (41) and located inside the hollow cavity; The inner shielding cylinder (43) is embedded inside the outer shielding cylinder (42); A Laval nozzle (44) is installed inside the inner shielding cylinder (43) to generate an ultrasonic molecular beam; The gas supply pipe (45) passes through the outer flange (41) and is connected to the Laval nozzle (44); A vacuum monitoring port (46) is installed on the side wall of the main body (40) of the device; The air extraction port (47) is installed on the side wall of the device body (40) away from the vacuum monitoring port (46); The air pressure measurement component (5) is connected to the ultrasonic molecular beam injection air path and the second air delivery path to monitor the air pressure of the two air paths; The amount of injected gas is measured by gas pressure measurement in two gas paths to increase plasma density.

2. The spherical tokamak feeding system based on ultrasonic molecular beam injection according to claim 1, characterized in that, Also includes: The first pressure reducing valve (301) is connected to the needle valve (2); The first needle valve (302) is connected at one end to the first pressure reducing valve (301) and at the other end to the gas tank (3).

3. The spherical tokamak feeding system based on ultrasonic molecular beam injection according to claim 2, characterized in that, Also includes: The second needle valve (303) is connected to the gas tank (3); The piezoelectric valve (304) is connected at one end to the second needle valve (303) and at the other end to the spherical tokamak inlet.

4. The spherical tokamak feeding system based on ultrasonic molecular beam injection according to claim 3, characterized in that, Also includes: An air bag (6) and a third needle valve (601) are connected in series to a third pipe. The fourth needle valve (401) and the fifth needle valve (402) are installed on the third pipe.

5. The spherical tokamak feeding system based on ultrasonic molecular beam injection according to claim 4, characterized in that, The barometric pressure measurement assembly (5) includes: The differential pressure sensor (501) is connected to the fourth needle valve (401); The sixth needle valve (502) is connected at one end to the differential pressure sensor (501) and at the other end to the second air supply path.

6. The spherical tokamak feeding system based on ultrasonic molecular beam injection according to claim 1, characterized in that, The outer shielding cylinder (42), the inner shielding cylinder (43), the Laval nozzle (44), and the gas delivery pipe (45) are all located on the same axis.

7. The spherical tokamak feeding system based on ultrasonic molecular beam injection according to claim 6, characterized in that, The aperture of the Laval nozzle is 0.2 mm.

8. The spherical tokamak feeding system based on ultrasonic molecular beam injection according to claim 1, characterized in that, The ultrasonic molecular beam injection device (4) also includes: Hydrogen Alpha observation window (48) is installed on the outer flange (41).

9. The spherical tokamak feeding system based on ultrasonic molecular beam injection according to claim 8, characterized in that, The ultrasonic molecular beam injection device (4) also includes: A valve lead seat (49) is installed on the outer flange (41).

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