Hall thruster with strong constraint electrons

Abstract

A Hall thruster with strong confinement electrons belongs to the technical field of electric propulsion and comprises an inner iron core, an inner coil, channel insulating ceramics, an insulator, a bottom plate, an outer coil, a magnetic conductive cover, a gas distributor, an inner magnetic pole, an outer magnetic pole, an anode magnetic screen integrated channel, inner ceramics, outer ceramics and an anode insulating spacer. An anode magnetic screen integrated channel spaced from the inner coil and the outer coil is arranged between the inner coil and the outer coil, the anode magnetic screen integrated channel is an internally and externally concentric annular body, the anode magnetic screen integrated channel and the bottom plate are insulated and isolated, the gas distributor is arranged at the bottom of the anode magnetic screen integrated channel, and the gas distributor and the anode magnetic screen integrated channel are insulated and isolated; the inner ceramic and the outer ceramic are respectively arranged at the tops of the inner wall and the outer wall of the anode and magnetic screen integrated channel, and the magnetic screen and anode integrated channel, the inner ceramic and the outer ceramic form a bottle-shaped magnetic trap in the channel. According to the anode and magnetic screen integrated channel, the restraining capacity on electrons is improved, so that the ionization rate is improved, and the overall performance of the thruster is optimized.

Description

Technical Field

[0001] The invention relates to a high-voltage Hall thruster, in particular to a high-voltage Hall thruster which utilizes a bottle-shaped magnetic trap to confine electrons, and belongs to the technical field of electric propulsion. Background Art

[0002] Hall thruster is an electric propulsion device commonly used in aerospace propulsion. There are mutually orthogonal radial magnetic fields and axial electric fields in its channel. The electrons emitted by the cathode are constrained by the magnetic field and perform cyclotron motion along the magnetic lines of force. Neutral atoms are injected from the gas distributor at the bottom of the channel, collide with the electrons to generate ions, and the ions are accelerated and ejected toward the channel outlet under the action of the axial electric field force, thereby generating thrust.

[0003] In recent years, the diversified development of space missions has put forward the demand for high specific impulse propulsion, which has promoted the development of high specific impulse Hall thrusters. The specific impulse of Hall thrusters is proportional to the square root of the discharge voltage. Therefore, increasing the discharge voltage is the most effective means to achieve high specific impulse. However, under high-voltage discharge conditions, the energy gained by electrons when moving toward the anode increases significantly, resulting in a significant increase in electron temperature, which in turn causes the electron migration speed to increase and the electron current to increase. This situation significantly increases the loss of electrons to the anode, resulting in an increase in the heat load of the anode, which in turn causes the anode to overheat or even melt, reducing the stability and reliability of the Hall thruster, and ultimately affecting the overall performance of the thruster.

[0004] It can be seen that the above problems are mainly caused by the insufficient confinement ability of the magnetic field on high-energy electrons, so it becomes crucial to control the behavior of electrons under high voltage. The magnetic field plays a key role in confining electrons. By reasonably designing the magnetic field, the movement of electrons can be effectively restricted, the loss of electrons can be reduced, and the electrons can be fully involved in the ionization process of the gas working fluid, thereby improving the performance of the thruster. Therefore, how to design a magnetic field that can effectively confine electrons has become an important topic in current design research.

[0005] The anode of a traditional Hall thruster is located at the bottom of the ceramic channel, with a limited area for collecting current and difficulty in heat dissipation. This design can easily cause the anode to overheat or even melt locally when the Hall thruster is working, affecting the performance of the thruster and the stability of discharge. For example, patent application No. 20221024239.8 relates to an integrated magnetic shield anode structure of a low-power Hall thruster, including an anode magnetic shield, an anode gas outlet plate, and an anode upper cover plate, which increases the heat dissipation area of ​​the anode. This structure is to solve the problem of poor discharge stability caused by the difficulty of heat dissipation of the anode deep in the ceramic channel; for example, patent application No. 20161107454.6 relates to a Hall thruster with a lightweight integrated anode, whose integrated anode has a U-shaped cavity structure, which increases the heat dissipation area of ​​the anode, and its cavity structure can improve the flow and distribution characteristics of the gas. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and to propose a Hall thruster with strong electron confinement to overcome the problems of anode overheating, low ionization efficiency and large electron loss of the prior Hall thruster when working at high voltage.

[0007] A Hall thruster for strong electron confinement comprises an inner iron core, an inner coil, a channel insulating ceramic, an insulator, a bottom plate, an outer coil, a magnetic cover, a gas distributor, an inner magnetic pole and an outer magnetic pole; the inner iron core and the magnetic cover are respectively placed on the upper surface of the bottom plate, the inner iron core is wound with an inner coil, and the inner magnetic pole and the outer magnetic pole are respectively placed on the top of the inner iron core and the magnetic cover; it comprises an anode magnetic shield integrated channel, a channel insulating ceramic, an inner ceramic, an outer ceramic and an anode insulating gasket; an anode magnetic shield integrated channel is arranged between the inner coil and the outer coil, and the inner coil and the outer coil are spaced apart from each other. The anode magnetic shield integrated channel is an annular body with inner and outer concentric parts. The gas distributor, the anode magnetic shield integrated channel and the bottom plate are connected as one. The anode magnetic shield integrated channel and the bottom plate are insulated and isolated. The gas distributor is arranged at the bottom of the anode magnetic shield integrated channel and the two are insulated and isolated. An outer coil is arranged between the anode magnetic shield integrated channel and the magnetic conductive cover. The inner ceramic and the outer ceramic are respectively placed on the top of the inner and outer walls of the anode magnetic shield integrated channel. The magnetic shield anode integrated channel, the inner magnetic pole, the inner ceramic, the outer ceramic and the outer magnetic pole form a bottle-shaped magnetic well in the channel.

[0008] The beneficial effects of the present invention compared with the prior art are as follows:

[0009] The present application designs an integrated anode magnetic shield channel, and sets a converging ceramic wall at the exit. The design structure has the following advantages. First, the structure simplifies the internal space of the thruster, reduces the radial size between the magnetic shields, and can form a stronger magnetic field to confine the electrons. Second, the converging ceramic wall has a convergence effect on the working gas in the channel, increasing the density of the working gas, thereby optimizing the direct bombardment of the electrons in the channel on the anode. Third, the integrated structure of the anode magnetic shield and the converging ceramic structure form a magnetic field configuration of a bottle-shaped magnetic trap inside the channel that can confine electrons, increasing the path and residence time of electrons in the channel, which is conducive to increasing the energy consumed by electrons in the process of returning to the anode. In summary, the present application can overcome the problems of anode overheating, low ionization efficiency, and large electron loss when the Hall thruster is working at high voltage.

[0010] The present application scheme is further described below with reference to the accompanying drawings and embodiments: BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic structural diagram of a Hall thruster for strongly confined electrons in the present application;

[0012] Figure 2 Schematic diagram of magnetic field line distribution at the channel outlet and magnetic trap of the embodiment. DETAILED DESCRIPTION

[0013] The embodiments of the technical solution of the present application are described in detail below in conjunction with the accompanying drawings. Unless otherwise specified, the technical terms or scientific terms used in the present application are generally understood by those skilled in the art.

[0014] The anode of a traditional Hall thruster is located at the bottom of the ceramic channel, with a limited area for collecting current and difficulty in heat dissipation. This design can easily cause the anode to overheat or even melt locally when the Hall thruster is working, affecting the performance of the thruster and the stability of the discharge. This is mainly concentrated on the structural layout of the separate magnetic shield, anode and channel.

[0015] In view of this, the present application provides a Hall thruster with strong electron confinement. Figure 1 A Hall thruster using a bottle-shaped magnetic trap to confine electrons is shown, which comprises an inner core 1, an inner coil 2, an insulator 5, a bottom plate 6, an outer coil 7, a magnetic cover 8, a gas distributor 13, an inner magnetic pole 15 and an outer magnetic pole 9; the inner core 1 and the magnetic cover 8 are respectively placed on the upper surface of the bottom plate 6, the inner core 1 is wound with the inner coil 2, the inner magnetic pole 15 and the outer magnetic pole 9 are respectively placed on the top of the inner core 1 and the magnetic cover 8; it comprises an anode magnetic shield integrated channel 3, a channel insulating ceramic 4, an inner ceramic 11-1, an outer ceramic 11-2 and an anode insulating gasket 12; an anode magnetic shield integrated channel 3 is arranged between the inner coil 2 and the outer coil 7 to be spaced from the two.

[0016] The anode magnetic shield integrated channel 3 is a ring body with inner and outer concentric parts. The gas distributor 13, the anode magnetic shield integrated channel 3 and the bottom plate 6 are connected as a whole. The anode magnetic shield integrated channel 3 and the bottom plate 6 are insulated and isolated. The gas distributor 13 is arranged at the bottom of the anode magnetic shield integrated channel 3 and the two are insulated and isolated. An outer coil 7 is arranged between the anode magnetic shield integrated channel 3 and the magnetic conductive cover 8. The inner ceramic 11-1 and the outer ceramic 11-2 are respectively placed on the top of the inner and outer walls of the anode magnetic shield integrated channel 3. The magnetic shield anode integrated channel 3, the inner ceramic 11-1 and the outer ceramic 11-2 form a bottle-shaped magnetic well in the channel.

[0017] The beneficial effects of this embodiment are: 1) The magnetic shield anode integrated channel integrates the magnetic shield, anode and channel, which reduces the distance between the magnetic shields, increases the anode area, improves the anode thermal environment, and enhances the magnetic field strength in the channel. 2) The magnetic shield anode integrated channel, inner and outer magnetic poles, and inner and outer ceramics form a bottle-shaped magnetic trap at the channel outlet, which confines electrons in the bottle-shaped area, increases electron density, improves ionization rate, and optimizes the overall performance of the thruster. 3) The inner and outer ceramics block the magnetic lines of force that directly intersect the front end of the anode, preventing high-energy electrons from hitting the anode along the magnetic lines of force. 4) The gas distributor is isolated and heat-insulated from the anode magnetic shield integrated channel, reducing the flow rate of the working gas and making ionization more complete.

[0018] The Hall thruster of this embodiment is designed with an anode magnetic shield integrated channel 3, which is used as a magnetic shield, anode and channel, and has three functions. It replaces the traditional separated magnetic shield, anode and channel structure, simplifies the anode structure, increases the anode's electron receiving and heat dissipation area, shortens the radial distance between the magnetic shields, and helps to improve the magnetic field strength and enhance the electron confinement capability; by arranging the inner ceramic 11-1 and the outer ceramic 11-2 at the outlet of the anode magnetic shield integrated channel 3, the magnetic lines of force that directly intersect with the front end of the anode magnetic shield integrated channel 3 are blocked, and high-energy electrons are prevented from directly bombarding the anode along the magnetic lines of force, thereby reducing the thermal deposition on the anode surface. At the same time, the radial distance L1 between the outer surface of the inner ceramic 11-1 and the inner surface of the outer ceramic 11-2 is less than the radial distance L2 between the inner and outer walls of the anode magnetic shield integrated channel 3, and the following relationship L2>L1 is satisfied, so that the discharge channel forms a bottle-shaped magnetic trap structure, which helps to gather the working gas, increase the gas density in the channel, thereby improving the ionization rate and optimizing the thruster performance.

[0019] When the Hall thruster of this embodiment is working, the magnetic lines of force that form the magnetic field in the channel will start from one end of the magnetic pole, form a bottle-shaped magnetic trap structure inside the channel, and then connect the magnetic pole at the other end. This magnetic field configuration prolongs the path and time of electrons in the channel, increases the participation of electrons in ionization, collision and excitation, and improves the degree of ionization, thereby further optimizing the performance of the thruster. In addition, in the process of electrons returning to the anode, they will participate in collision, ionization and excitation, resulting in an increase in the ionization rate, while the electron energy is reduced, thereby reducing the energy of the electrons returning to the anode and improving the thermal environment of the anode. This design increases the constraint on electrons under high voltage (such as above 600V), increases the density of the working gas, is conducive to the efficient discharge of the thruster, and effectively reduces the problem of anode overheating, further optimizing the overall performance of the thruster.

[0020] Exemplarily, the distance L1 between the outer surface of the inner ceramic 11-1 and the inner surface of the outer ceramic 11-2 is determined by the extent to which the magnetic force lines from the magnetic pole to the front end of the anode magnetic shield integrated channel 3 are covered by the inner and outer ceramics. The inner ceramic 11-1 is used to shield the electrons of the high-intensity magnetic force lines directed along the inner magnetic pole 15 to the front end of the anode magnetic shield integrated channel 3, and the outer ceramic 11-2 is used to shield the electrons of the high-intensity magnetic force lines directed along the outer magnetic pole 9 to the front end of the anode magnetic shield integrated channel 3. By changing the radial distance and axial length of the inner ceramic 11-1 and the outer ceramic 11-2, the magnetic force lines intersecting the anode magnetic shield integrated channel 3 are shielded, and high-energy electrons are prevented from directly bombarding the anode magnetic shield integrated channel 3 along the magnetic force lines, so as to avoid the degradation of thruster performance caused by overheating of the anode magnetic shield integrated channel 3.

[0021] Exemplarily, the inner magnetic pole 15 and the inner ceramic 11-1 are provided with an inner baffle 14 on the top, and the magnetic shield 9 and the outer ceramic 11-2 are provided with an outer baffle 10 on the top, and the inner ceramic 11-1 and the outer ceramic 11-2 are fixed by the inner baffle 14 and the outer baffle 10 on the top. The bottle-shaped magnetic field structure formed by the inner magnetic pole 15 and the outer magnetic pole 9 inside the anode magnetic shield integrated channel 3 can constrain electrons. Electrons return to the anode magnetic shield integrated channel 3 from the magnetic field structure through a series of collisions, ionizations and excitations, which reduces the energy returned to the anode magnetic shield integrated channel 3, thereby optimizing the thermal environment of the magnetic shield anode integrated channel 3.

[0022] Exemplarily, an anode insulating gasket 12 and an insulator 5 are provided between the gas distributor 13 and the magnetic shield anode integrated channel 3. A channel insulating ceramic 4 is provided between the anode magnetic shield integrated channel 3 and the bottom plate 6. Insulation isolation is to prevent the gas distributor 13 from being overheated, which may cause the working gas flow rate to increase and cause insufficient ionization.

[0023] The channel insulating ceramic 4, insulator 5 and insulating gasket 12 are all made of high temperature resistant insulating ceramic materials. Preferably, alumina ceramic is preferably selected according to the hardness and processability of the material to ensure deformation compensation capability at high temperature, thereby ensuring the tightness and sealing of the discharge channel as a whole during the operation of the Hall thruster.

[0024] The anode magnetic shield integrated channel 3 is made of a magnetically conductive metal material.

[0025] Preferably, the magnetic conductive metal material is electrical pure iron DT4C.

[0026] The magnetic field structure of the bottle-shaped magnetic trap is further explained below with reference to an embodiment.

[0027] Example 1

[0028] Based on the above research plan, this implementation case simulated the magnetic field of the high-voltage Hall thruster. During the simulation, the anode magnetic shield integrated channel uses channel insulation ceramics, insulators and anode insulation gaskets to ensure insulation between it and other components. The inner and outer ceramics are placed above the anode magnetic shield integrated channel and fixed in place by inner and outer baffles.

[0029] exist Figure 2 In the figure, the middle blue line represents the center line of the channel, and the other blue lines and the areas they are located in represent the boundaries of the inner and outer ceramics, the anode and the magnetic poles. The red area is the magnetic trap structure in the channel. The magnetic lines of force start from the inner magnetic pole and form a bottle-shaped structure in the channel, and then return to the outer magnetic pole. This magnetic field structure can effectively confine electrons, increase the electron density in the ionization zone, and increase the ionization rate, thereby improving the specific impulse and performance of the thruster.

[0030] The present invention has been disclosed as above with preferred implementation cases, but it is not used to limit the present invention. Any technician familiar with the profession can make slight changes or modifications to equivalent implementation cases with equivalent changes by using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present invention, which still fall within the scope of the technical solution of the present invention.

Claims

1. A Hall thruster for strongly confined electrons, comprising an inner iron core (1), an inner coil (2), an insulator (5), a bottom plate (6), an outer coil (7), a magnetic cover (8), a gas distributor (13), an inner magnetic pole (15) and an outer magnetic pole (9); the inner iron core (1) and the magnetic cover (8) are respectively placed on the upper surface of the bottom plate (6); the inner iron core (1) is wound with the inner coil (2); the inner magnetic pole (15) and the outer magnetic pole (9) are respectively placed on the top of the inner iron core (1) and the magnetic cover (8); Features: The invention also comprises an anode magnetic shield integrated channel (3), an inner ceramic (11-1), an outer ceramic (11-2) and an anode insulating gasket (12); an anode magnetic shield integrated channel (3) is provided between the inner coil (2) and the outer coil (7) and is spaced from the inner coil (2) and the outer coil (7); the anode magnetic shield integrated channel (3) is an annular body with inner and outer concentricities; the gas distributor (13), the anode magnetic shield integrated channel (3) and the bottom plate (6) are connected as a whole; the anode magnetic shield integrated channel (3) and the bottom plate (6) are insulated and isolated. The gas distributor (13) is arranged at the bottom of the anode magnetic shield integrated channel (3) and the two are insulated and isolated. An outer coil (7) is arranged between the anode magnetic shield integrated channel (3) and the magnetic conductive cover (8). The inner ceramic (11-1) and the outer ceramic (11-2) are respectively placed on the top of the inner and outer walls of the anode magnetic shield integrated channel (3). The magnetic shield anode integrated channel (3), the inner magnetic pole (15), the inner ceramic (11-1), the outer ceramic (11-2) and the outer magnetic pole (9) form a bottle-shaped magnetic well in the channel.

2. A Hall thruster for strongly confined electrons according to claim 1, characterized in that: The radial distance between the outer surface of the inner ceramic (11-1) and the inner surface of the outer ceramic (11-2) is smaller than the radial distance between the inner and outer wall surfaces of the anode magnetic shield integrated channel (3).

3. The Hall thruster for strongly confined electrons according to claim 1, characterized in that: The distance between the outer surface of the inner ceramic (11-1) and the inner surface of the outer ceramic (11-2) is determined by the extent to which the magnetic force lines from the magnetic pole to the front end of the anode magnetic shield integrated channel (3) are covered by the inner and outer ceramics.

4. The Hall thruster for strongly confined electrons according to claim 1, characterized in that: An anode insulating gasket (12) and an insulator (5) are arranged between the gas distributor (13) and the magnetic shield anode integrated channel (3).

5. The Hall thruster for strongly confined electrons according to claim 1, characterized in that: A channel insulating ceramic (4) is provided between the anode magnetic shield integrated channel (3) and the bottom plate (6).

6. The Hall thruster for strongly confined electrons according to claim 1, characterized in that: An inner baffle (14) is provided on the top of the inner magnetic pole (15) and the inner ceramic (11-1), and an outer baffle (10) is provided on the top of the magnetic conductive cover (9) and the outer ceramic (11-2).

7. The Hall thruster for strongly confined electrons according to claim 1, characterized in that: The inner ceramic (11-1) is used to shield electrons along the high-intensity magnetic lines of force directed to the front end of the anode magnetic shield integrated channel (3) along the inner magnetic pole (15), and the outer ceramic (11-2) is used to shield electrons along the high-intensity magnetic lines of force directed to the front end of the anode magnetic shield integrated channel (3) along the outer magnetic pole (9).

8. The Hall thruster for strongly confined electrons according to claim 1, characterized in that: The anode magnetic shield integrated channel (3) is made of a magnetically conductive metal material.

9. A Hall thruster for strongly confined electrons according to claim 8, characterized in that: The magnetic conductive metal material is electrical pure iron DT4C.

10. The Hall thruster for strongly confined electrons according to claim 1, characterized in that: The channel insulating ceramic (4), the insulator (5) and the insulating gasket (12) are all made of high-temperature resistant insulating ceramic material.

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