Adjustable magnetic circuit structure suitable for low-power Hall thruster

Abstract

The invention relates to the technical field of spaceflight and plasma propulsion, in particular to an adjustable magnetic circuit structure suitable for a low-power Hall thruster, which comprises an inner magnetic pole, a magnetic conductive inner core, an inner coil, an inner magnetic screen, a bottom plate, a magnetic conductive cover, a ceramic channel, an outer coil and an outer magnetic pole, one end of the magnetic conductive inner core is provided with an inner magnetic pole and an outer magnetic pole, the other end of the magnetic conductive inner core is provided with a bottom plate, the ceramic channel is arranged between the inner magnetic pole and the outer magnetic pole and is in contact with the bottom plate, and the inner coil and the inner magnetic screen are arranged between the inner magnetic pole and the bottom plate and are positioned on one side of the ceramic channel; the magnetic conductive cover is arranged between the outer magnetic pole and the bottom plate and located on the other side of the ceramic channel, a magnetic conductive gap is formed between the magnetic conductive cover and the bottom plate, an outer auxiliary transverse magnetic screen is arranged on the magnetic conductive cover, the outer coil is arranged in the magnetic conductive cover, and a hollow part is arranged at the bottom of the magnetic conductive cover.

Description

Technical Field

[0001] This invention relates to the fields of aerospace technology and plasma propulsion technology, and specifically to an adjustable magnetic circuit structure suitable for low-power Hall thrusters. Background Technology

[0002] A Hall thruster, also known as a Hall effect thruster, is a device that uses an electric field to accelerate propellant. The Hall thruster confines electrons in a magnetic field and uses these electrons to ionize the propellant, accelerating the ions to generate thrust and neutralizing the ions in the plume.

[0003] Hall thrusters, as a highly efficient electric propulsion device, have been widely used in satellite attitude and orbit control and deep space exploration missions. One of their core components is the magnetic circuit system. For example... Figure 1 As shown, traditional magnetic circuit systems are mainly designed based on xenon (Xe) gas as the working fluid. They typically consist of an inner magnetic pole 1, an outer magnetic pole 10, a magnetic shield 7, an inner coil 3, an outer coil 9, and an outer magnetic screen 12, etc., to form the required magnetic field in the discharge channel 11 region, thereby confining electrons in the E×B region and accelerating plasma.

[0004] However, for low-power Hall thrusters, due to power limitations, a smaller current-passing area is required. Low-power Hall thrusters are limited in size and weight. In addition, the limited space for coil layout makes it difficult for traditional magnetic circuit structures to simultaneously meet magnetic field optimization, resulting in difficulty in adjusting the magnetic field. Furthermore, after the thruster is reduced in size, it also faces the problem of poor heat dissipation. The anode is sandwiched between the inner and outer magnetic screens, and the heat it generates cannot be effectively radiated from the magnetic screen walls to the surroundings, leading to difficulties in heat dissipation. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the difficulty of the magnetic circuit structure in the prior art to simultaneously meet the magnetic field optimization, which makes it difficult to place the inner coil to meet the magnetic field requirements after the size is reduced, and the space for the inner coil layout is limited. At the same time, the thruster also faces the problem of poor heat dissipation after the volume is reduced. Thus, an adjustable magnetic circuit structure suitable for low-power Hall thrusters is provided.

[0006] To address the aforementioned technical problems, this invention provides an adjustable magnetic circuit structure suitable for low-power Hall thrusters, comprising: an inner magnetic pole and a magnetic core, an inner coil, an inner magnetic screen, a base plate, a magnetic shield, a ceramic channel, an outer coil, and an outer magnetic pole; one end of the magnetic core is provided with an inner magnetic pole and an outer magnetic pole, and the other end is provided with a base plate; the ceramic channel is located between the inner magnetic pole and the outer magnetic pole and is in contact with the base plate; the inner coil and the inner magnetic screen are located between the inner magnetic pole and the base plate and are situated on one side of the ceramic channel; the magnetic shield is located between the outer magnetic pole and the base plate and is situated on the other side of the ceramic channel; a magnetic gap is provided between the magnetic shield and the base plate; an outer auxiliary transverse magnetic screen is provided on the magnetic shield; the outer coil is located inside the magnetic shield; and a hollow portion is provided at the bottom of the magnetic shield.

[0007] Furthermore, the magnetic gap is 1 mm.

[0008] Furthermore, the external auxiliary transverse magnetic screen is perpendicular to the magnetic shield.

[0009] Furthermore, the outer coil is disposed inside the magnetic shield and is located between the outer auxiliary transverse magnetic screen and the outer magnetic pole.

[0010] Furthermore, the distance between one end of the inner magnetic screen and the base plate is X2, and the distance between the outer auxiliary transverse magnetic screen and the base plate is X3, where X2 is greater than X3.

[0011] Furthermore, X2 is 22mm and X3 is 16mm.

[0012] Furthermore, the gap between the inner and outer magnetic poles is called the magnetic pole gap X1, which is 8.5 mm.

[0013] Furthermore, the width of the ceramic channel is less than 8.5 mm.

[0014] Furthermore, the upper surface of the ceramic channel is located in the same plane as the inner and outer magnetic poles.

[0015] Furthermore, the cross-section of the ceramic channel is U-shaped.

[0016] The technical solution of this invention has the following advantages: The present invention provides an adjustable magnetic circuit structure suitable for low-power Hall thrusters, comprising: an inner magnetic pole and a magnetic core, an inner coil, an inner magnetic screen, a base plate, a magnetic shield, a ceramic channel, an outer coil, and an outer magnetic pole; one end of the magnetic core is provided with an inner magnetic pole and an outer magnetic pole, and the other end is provided with a base plate; the ceramic channel is located between the inner magnetic pole and the outer magnetic pole and is in contact with the base plate; the inner coil and the inner magnetic screen are located between the inner magnetic pole and the base plate and are located on one side of the ceramic channel; the magnetic shield is located between the outer magnetic pole and the base plate and is located on the other side of the ceramic channel; a magnetic gap is provided between the magnetic shield and the base plate; an outer auxiliary transverse magnetic screen is provided on the magnetic shield; the outer coil is located inside the magnetic shield; and a hollow portion is provided at the bottom of the magnetic shield.

[0017] A ceramic channel is installed between the base plate and the inner and outer magnetic poles. An inner coil and an inner magnetic screen are installed between the magnetic core and the ceramic channel. The inner magnetic screen is vertically arranged on the base plate, meaning it is positioned on the side of the ceramic channel closest to the magnetic core. This design ensures strong adaptability of the Hall thruster to low power applications. The inner magnetic screen has a vertical plate-like structure arranged inside the discharge channel, extending axially to maximize the space available for coil arrangement. This allows for the installation of a larger number of coil turns, increasing the magnetic field strength—meeting the magnetic field strength requirements without increasing the volume. Furthermore, this adjustable magnetic circuit structure is designed for low-power thrusters below 100 watts, fully considering the requirements for low power consumption and high performance. This results in a compact and efficient magnetic circuit structure suitable for low-power applications.

[0018] The magnetic shield is positioned on the side of the ceramic channel away from the magnetic core. A magnetic gap is created between the shield and the base plate, and this gap can be adjusted via a mechanical structure. This allows for flexible changes in the closed magnetic circuit length, thereby shifting the position of the zero magnetic point in the magnetic field. Compared to traditional fixed structures, this adjustable magnetic circuit structure optimizes the magnetic field configuration according to different thrust and voltage conditions, bringing the relative positions of the ionization and acceleration regions to the optimal state, improving ionization efficiency and reducing high-energy ion bombardment of the wall surface.

[0019] The external auxiliary transverse magnetic screen mounted on the magnetic shield gives this adjustable magnetic circuit structure the advantage of an adjustable zero magnetic point, enhancing thermal management performance. The external auxiliary transverse magnetic screen is arranged laterally outside the discharge channel, forming an integrated structure with the magnetic shield. This not only simplifies the structure but also allows for a perforated section at the bottom of the external auxiliary transverse magnetic screen, enabling the ceramic channel to radiate directly outwards. This expands the heat radiation path and enhances heat dissipation from within the channel to the outside, allowing the magnetic circuit to more effectively dissipate heat through external radiation during heating, thereby improving the system's heat dissipation performance. This reduces the difficulty of thruster heat dissipation design and prevents the magnetic circuit and coils from being affected by overheating.

[0020] The summary section is provided to present the chosen concepts in a simplified form, which will be further described in the detailed description below. The summary section is not intended to identify essential or necessary features of this disclosure, nor is it intended to limit the scope of this disclosure. Attached Figure Description

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

[0022] Figure 1 This is a schematic diagram of the structure of a conventional Hall thruster magnetic circuit provided by the present invention; Figure 2 A schematic diagram of the adjustable magnetic circuit structure for a low-power Hall thruster provided by the present invention; Figure 3 The magnetic field configuration diagram of the adjustable magnetic circuit structure suitable for low-power Hall thrusters provided by the present invention; Figure 4 The magnetic field strength distribution diagram of the channel centerline of the adjustable magnetic circuit structure suitable for low-power Hall thrusters provided by the present invention; Figure 5 A schematic diagram of the magnetic shield structure for the adjustable magnetic circuit structure of a low-power Hall thruster provided by the present invention.

[0023] Explanation of reference numerals in the attached figures: 1. Inner magnetic pole; 2. Magnetic core; 3. Inner coil; 4. Inner magnetic screen; 5. Base plate; 6. Magnetic gap; 7. Magnetic cover; 71. Outer auxiliary transverse magnetic screen; 72. Hollowed-out part; 8. Ceramic channel; 9. Outer coil; 10. Outer magnetic pole; 11. Discharge channel; 12. Outer magnetic screen. Detailed Implementation

[0024] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this disclosure. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0025] The preferred embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0026] Please see Figures 2 to 5As shown, the present invention provides an adjustable magnetic circuit structure suitable for a low-power Hall thruster, comprising: an inner magnetic pole 1 and a magnetic core 2, an inner coil 3, an inner magnetic screen 4, a base plate 5, a magnetic shield 7, a ceramic channel 8, an outer coil 9, and an outer magnetic pole 10; one end of the magnetic core 2 is provided with the inner magnetic pole 1 and the outer magnetic pole 10, and the other end is provided with the base plate 5; the ceramic channel 8 is located between the inner magnetic pole 1 and the outer magnetic pole 10 and is in contact with the base plate 5; the inner coil 3 and the inner magnetic screen 4 are located between the inner magnetic pole 1 and the base plate 5 and are located on one side of the ceramic channel 8; the magnetic shield 7 is located between the outer magnetic pole 10 and the base plate 5 and is located on the other side of the ceramic channel 8; a magnetic gap 6 is provided between the magnetic shield 7 and the base plate 5; an outer auxiliary transverse magnetic screen 71 is provided on the magnetic shield 7; the outer coil 9 is located inside the magnetic shield 7; and a hollow portion 72 is provided at the bottom of the magnetic shield 7.

[0027] A ceramic channel 8 is installed between the base plate 5 and the inner magnetic pole 1 and outer magnetic pole 10. An inner coil 3 and an inner magnetic screen 4 are installed between the magnetic core 2 and the ceramic channel 8. The inner magnetic screen 4 is vertically arranged on the base plate 5, that is, the inner magnetic screen 4 is located on the side of the ceramic channel 8 closer to the magnetic core 2, which makes the Hall thruster highly adaptable to low power. The inner magnetic screen 4 is arranged in a vertical plate-like structure inside the discharge channel 11 and extends axially to maximize the space for coil arrangement, which can ensure the installation of more coil turns and improve the magnetic field strength, that is, meet the magnetic field strength requirements without increasing the volume. At the same time, this adjustable magnetic circuit structure is designed for low-power thrusters below 100 watts, and fully considers the requirements of low power consumption and high performance, making the magnetic circuit structure compact and efficient, suitable for low-power applications.

[0028] The magnetic shield 7 is positioned on the side of the ceramic channel 8 away from the magnetic core 2. A magnetic gap 6 is provided between the magnetic shield 7 and the base plate 5. This gap 6 can be adjusted via a mechanical structure, flexibly changing the closed length of the magnetic circuit and thus moving the position of the zero magnetic point in the magnetic field. Compared to traditional fixed structures, this adjustable magnetic circuit structure can optimize the magnetic field configuration according to different thrust and voltage conditions, adjusting the relative positions of the ionization region and the acceleration region to the optimal state, improving ionization efficiency and reducing high-energy ion bombardment of the wall surface.

[0029] The external auxiliary transverse magnetic screen 71 mounted on the magnetic shield 7 gives this adjustable magnetic circuit structure the advantage of an adjustable zero magnetic point and enhances thermal management performance. The external auxiliary transverse magnetic screen 71 is arranged transversely outside the discharge channel 11, forming an integrated structure with the magnetic shield 7. This not only simplifies the structure but also allows for a perforated section 72 at the bottom of the external auxiliary transverse magnetic screen 71, enabling the ceramic channel 8 to directly radiate heat outwards. This expands the heat radiation path and enhances the dissipation of heat from within the channel to the outside, allowing the magnetic circuit to more effectively dissipate heat through external radiation during heating, thereby enhancing the system's heat dissipation performance. This reduces the difficulty of thruster heat dissipation design and prevents the magnetic circuit and coils from being affected by overheating.

[0030] In this embodiment, the magnetic gap 6 is 1 mm. This magnetic gap 6 is the distance between the magnetic shield 7 and the base plate 5, which is 1 mm x 4. Of course, the magnetic gap 6 can also be other parameters, such as 0.5 mm.

[0031] Of course, these magnetic gaps 6 can be finely adjusted by using non-magnetic shims, thereby moving the zero magnetic point in the discharge channel 11 along the axial direction and achieving fine optimization of the magnetic field distribution.

[0032] Meanwhile, the external auxiliary transverse magnetic screen 71 is perpendicular to the magnetic shield 7. That is, the external auxiliary transverse magnetic screen 71 is arranged horizontally, and it is arranged horizontally outside the discharge channel 11, forming an integral structure with the magnetic shield 7, thus ensuring the strength and rigidity of the magnetic shield 7.

[0033] The outer coil 9 is located inside the magnetic shield 7 and between the outer auxiliary transverse magnetic screen 71 and the outer magnetic pole 10. That is, the outer coil 9 and the inner coil 3 have different sizes, with the outer coil 9 being smaller than the inner coil 3.

[0034] Figure 3 As an example of the simulation results in FEMM, the centerline radius of the Hall thruster channel is set to 21.5 mm, the magnetic pole gap between the inner magnetic pole 1 and the outer magnetic pole 10 is set to 18.5 mm, the magnetic guide gap between the base plate and the integrated magnetic guide cover is set to 1 mm, the height of the inner magnetic screen is 22 mm, and the height of the outer auxiliary transverse magnetic screen on the magnetic guide cover is 16 mm. Under the given coil excitation current, a symmetrical magnetic field distribution is formed, and a zero magnetic point exists.

[0035] Figure 4 The graph shows the magnetic field strength distribution curve along the centerline of the example channel. The horizontal axis represents the axial distance in mm, and the vertical axis represents the magnetic field strength in Telsa. The maximum magnetic field strength Bmax is 0.0244 Telsa, or 244 Gs.

[0036] like Figure 5 As shown, a hollowed-out treatment can be made at the bottom of the magnetic shield 7, that is, a hollowed-out part 72 is set. This does not affect the magnetic conductivity. The ceramic channel 8 can directly radiate to the outside, which expands the heat radiation path and enhances the heat dissipation from the ceramic channel 8 to the outside. This allows the magnetic circuit to more effectively dissipate heat through external radiation when heated, thereby enhancing the heat dissipation performance of the system.

[0037] In some optional embodiments, the distance between one end of the inner magnetic screen 4 and the base plate 5 is X2, and the distance between the outer auxiliary transverse magnetic screen 71 and the base plate 5 is X3, where X2 is greater than X3.

[0038] Wherein, X2 is 22mm and X3 is 16mm.

[0039] In this embodiment, the gap between the inner magnetic pole 1 and the outer magnetic pole 10 is the magnetic pole gap X1, which is 8.5 mm. The width of the ceramic channel 8 is less than 8.5 mm.

[0040] Furthermore, the upper surface of the ceramic channel 8 is located in the same plane as the inner magnetic pole 1 and the outer magnetic pole 10. The cross-section of the ceramic channel 8 is U-shaped, which facilitates the placement of the discharge channel 11 within the ceramic channel 8.

[0041] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An adjustable magnetic circuit structure suitable for low-power Hall thrusters, characterized in that, include: Inner magnetic pole (1) and magnetic core (2), inner coil (3), inner magnetic screen (4), base plate (5), magnetic cover (7), ceramic channel (8), outer coil (9), and outer magnetic pole (10); One end of the magnetic core (2) is provided with an inner magnetic pole (1) and an outer magnetic pole (10), and the other end is provided with a base plate (5). The ceramic channel (8) is located between the inner magnetic pole (1) and the outer magnetic pole (10) and is in contact with the base plate (5). The inner coil (3) and the inner magnetic screen (4) are located between the inner magnetic pole (1) and the base plate (5) and are located on one side of the ceramic channel (8). The magnetic shield (7) is located between the outer magnetic pole (10) and the base plate (5), and is located on the other side of the ceramic channel (8). A magnetic gap (6) is provided between the magnetic shield (7) and the base plate (5). An outer auxiliary transverse magnetic screen (71) is provided on the magnetic shield (7). An outer coil (9) is located inside the magnetic shield (7), and a hollow part (72) is provided at the bottom of the magnetic shield (7).

2. The adjustable magnetic circuit structure for a low-power Hall thruster according to claim 1, characterized in that, The magnetic gap (6) is 1 mm.

3. The adjustable magnetic circuit structure for a low-power Hall thruster according to claim 2, characterized in that, The external auxiliary transverse magnetic screen (71) is perpendicular to the magnetic shield (7).

4. The adjustable magnetic circuit structure for a low-power Hall thruster according to claim 3, characterized in that, The outer coil (9) is located inside the magnetic shield (7) and between the outer auxiliary transverse magnetic screen (71) and the outer magnetic pole (10).

5. An adjustable magnetic circuit structure suitable for a low-power Hall thruster according to any one of claims 1-4, characterized in that, The distance between one end of the inner magnetic screen (4) and the base plate (5) is X2, and the distance between the outer auxiliary transverse magnetic screen (71) and the base plate (5) is X3, where X2 is greater than X3.

6. The adjustable magnetic circuit structure for a low-power Hall thruster according to claim 5, characterized in that, X2 is 22mm, and X3 is 16mm.

7. The adjustable magnetic circuit structure for a low-power Hall thruster according to claim 5, characterized in that, The gap between the inner magnetic pole (1) and the outer magnetic pole (10) is called the magnetic pole gap X1, which is 8.5 mm.

8. The adjustable magnetic circuit structure for a low-power Hall thruster according to claim 7, characterized in that, The width of the ceramic channel (8) is less than 8.5 mm.

9. The adjustable magnetic circuit structure for a low-power Hall thruster according to claim 7, characterized in that, The upper surface of the ceramic channel (8) is in the same plane as the inner magnetic pole (1) and the outer magnetic pole (10).

10. The adjustable magnetic circuit structure for a low-power Hall thruster according to claim 1, characterized in that, The cross-section of the ceramic channel (8) is U-shaped.

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