Kilowatt hall electric thruster based on aton type magnetic layer structure

Abstract

The application provides a kilowatt Hall electric thruster based on an ATON type magnetic layer structure, which comprises an anode, a discharge channel and a magnetic circuit structure, and the magnetic circuit structure comprises an inner magnetic pole, an outer magnetic pole, an inner coil, an outer coil and an additional coil. A ceramic sleeve constitutes a plasma discharge area, and a lower end of the ceramic sleeve is a krypton working medium inlet, and an upper end of the ceramic sleeve is a krypton working medium outlet. The application constructs a positive and negative gradient magnetic field and a zero magnetic area at the axial line of the discharge channel through the additional coil, optimizes the magnetic field configuration, makes the krypton working medium ion flow gather at the axial line of the channel, reduces wall collision loss and plume divergence loss, and thus improves the working medium ionization efficiency and the thruster performance, and is suitable for kilowatt Hall electric propulsion.

Description

Technical Field

[0001] This invention belongs to the field of electric propulsion technology, specifically relating to a kilowatt-class Hall electric thruster based on an ATON-type magnetic layer structure. Background Technology

[0002] With the increasing number of space missions and the expansion of detection range, high-power, high-specific-impulse electric propulsion technology has become an important direction for future development. Compared with other electric propulsion technologies, Hall thruster technology has advantages such as high thrust-to-power ratio, simple structure, small size, and high reliability, and is currently the most widely used electric propulsion technology. According to incomplete statistics, since the beginning of the 21st century, the total number of electric rocket engines in orbit is approximately 320, of which nearly 180 are Hall thrusters, accounting for more than 50%, far exceeding the less than 25% of the second most widely used ion thrusters.

[0003] Based on power, Hall thrusters can be divided into low-power (hundred-watt) and high-power (kilowatt) models. Hundred-watt Hall thrusters generally suffer from lower performance and shorter lifespan. To address this, domestic and international research institutions have developed various technologies, including low surface-to-volume ratio Hall thrusters (CHTs), variable cross-section and anode optimization, magnetic anodes and metal-ceramic composite channels, permanent magnet excitation with zero excitation power consumption, wall-less technology, and magnetic shielding. Despite these advancements, hundred-watt Hall thrusters still suffer from a large plume divergence angle, significantly affecting their performance. In contrast, high-power Hall thrusters, due to their greater thrust, can improve spacecraft carrying capacity, reduce launch time, and can be used for orbit transfers and near-Earth exploration in the Earth-Moon system. They are considered a major option for future spacecraft propulsion systems and have broad application prospects in deep space exploration, where high thrust and launch duration are crucial. Many countries, led by the United States and Russia, are actively conducting research on high-power Hall thrusters.

[0004] Research on high-power Hall thrusters primarily focuses on improving their performance, thus requiring a deep understanding and analysis of the internal processes of the thruster's plasma discharge channel. This process is complex, encompassing gas ionization into plasma, plasma oscillation, interaction between plasma particles and the discharge channel walls, and the coupling of electromagnetic fields with particles. Improving thruster performance necessitates comprehensive consideration of the influence of multiple physical fields, including electric, magnetic, velocity, temperature, and particle distribution. Traditional coupled models and numerical plasma simulation methods are insufficient to meet the computational demands of such multi-physics applications. High-power Hall thrusters were first researched in Russia in the 1960s, and several models, such as the SPT-200, SPT-290, and D-160, have since been developed. Domestic research on high-power Hall thrusters is still in its early stages, with numerous technological gaps remaining.

[0005] When Hall thrusters are upgraded to kilowatt levels and krypton (Kr), a lower-cost and more abundant medium, are used as the working fluid, significant challenges arise. Krypton's ionization energy (approximately 14.0 eV) is higher than that of traditional xenon (approximately 12.1 eV), and its atoms are lighter and move faster. This results in a reduced collision ionization cross-section between electrons and krypton atoms under traditional magnetic field configurations, leading to incomplete ionization. Simultaneously, rapidly moving ions are more prone to colliding with the discharge channel walls, causing energy loss and erosion of the device walls. These problems severely limit the efficiency, specific impulse, and service life of kilowatt-level krypton Hall thrusters. In existing technologies, simply adjusting the magnetic field strength or changing the gas supply method cannot fundamentally solve this core problem caused by the mismatch between the working fluid characteristics and the magnetic field configuration. Summary of the Invention

[0006] To address the problems of existing technologies, the present invention aims to provide a kilowatt-level Hall thruster based on an ATON-type magnetic layer structure, which improves the ionization efficiency of krypton working fluid and reduces ion wall collisions and plume divergence by optimizing the magnetic field configuration.

[0007] The present invention achieves the aforementioned technical effect through the following technical solution: This invention provides a kilowatt-level Hall thruster based on an ATON-type magnetic layer structure, comprising an anode, a discharge channel, and a magnetic circuit structure. The magnetic circuit structure includes an inner magnetic pole and an outer magnetic pole. The inner magnetic pole is fixed on the base plate and wound with an inner coil and an additional coil. The outer magnetic pole is fixed on the base plate and wound with an outer coil. The ceramic sleeve forms the plasma discharge region, with a krypton inlet at the lower end and a krypton outlet at the upper end. The anode is located inside the ceramic sleeve; The additional coil is configured to form a saddle-shaped magnetic field configuration convex to the anode at the central axis of the discharge channel. This magnetic field configuration includes a zero magnetic region formed in the anode region and positive and negative magnetic field gradient regions located on both sides of the zero magnetic region.

[0008] Preferably, the zero magnetic region is located near the top axial position of the anode.

[0009] Preferably, the inner magnetic pole, inner coil, auxiliary coil, outer magnetic pole, outer coil, and base plate are all made of magnetically conductive material.

[0010] Preferably, the anode is made of 1Cr18Ni9Ti stainless steel; the outer magnetic pole and the base plate are made of electrical pure iron DT4C; the inner magnetic pole and the auxiliary coil are made of iron-cobalt-vanadium soft magnetic alloy with high saturation magnetic induction intensity; and the excitation coils of the inner coil, outer coil and auxiliary coil are made of copper wire.

[0011] Preferably, the inner coil, outer coil, and auxiliary coil are made of high-temperature resistant copper wire wound on a frame and encapsulated with insulating glue, and the frame is made of a non-magnetic material.

[0012] Preferably, the skeleton is made of titanium alloy TC4.

[0013] Preferably, the inner coil and the ceramic sleeve have a gap in the radial direction.

[0014] Preferably, the additional coil and the ceramic sleeve are provided with a gap in the radial direction.

[0015] Preferably, the cross-section of the annular channel formed by the ceramic sleeve is L-shaped.

[0016] Preferably, the Hall thruster operates under the conditions of a discharge voltage of 368V, a power of 1360W, and a krypton flow rate of 4.2 mg / s, and can generate a thrust of at least 83mN and a specific impulse of more than 2016s.

[0017] The present invention provides a kilowatt-level Hall thruster based on an ATON-type magnetic layer structure, which has the following significant advantages compared with the prior art: By introducing an additional coil, an ATON-type saddle-shaped magnetic field configuration matching the physical properties of krypton was creatively constructed. The strong magnetic field gradient region of this configuration effectively confines electrons, extending their path and allowing them to fully collide and ionize with krypton atoms, thus solving the fundamental problem of difficult krypton ionization. The convex magnetic field configuration towards the anode focuses the generated krypton ion flow near the central axis of the discharge channel, significantly reducing collisions between ions and the channel wall. This reduces energy loss and wall erosion, as well as the plume divergence angle, resulting in higher specific impulse and thrust stability. The construction of a zero-magnetic region near the anode provides a "channel" for electrons to reach the anode, significantly reducing sheath voltage loss and improving overall propulsion efficiency. A well-defined radial gap design between the coil and the ceramic sleeve effectively isolates heat conduction. The selected high-temperature resistant and magnetically conductive materials ensure reliable operation and long lifespan under kilowatt-level high-power, high-temperature environments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention.

[0019] Figure 2 The magnetic field configuration and intensity distribution diagram of the plasma discharge channel shows the saddle-shaped magnetic field and the zero magnetic region.

[0020] Figure 3 The diagram shows the potential and electric field intensity distribution in the plasma discharge channel, illustrating the potential drop in the acceleration region.

[0021] Figure 4This is a radial distribution diagram of ion velocities in the plasma discharge channel, showing the peak velocity along the central axis.

[0022] Figure 5 The time-domain distribution of ion number density in the plasma discharge channel shows the stable discharge process.

[0023] Figure 6 This is an axial distribution diagram of the ion number in the plasma discharge channel, showing the location of the ion density peak.

[0024] Wherein: 1-inner magnetic pole, 2-inner coil, 3-discharge channel, 4-outer magnetic pole, 5-outer coil, 6-auxiliary coil, 7-ceramic sleeve, 8-anode, 9-krypton working fluid outlet, 10-krypton working fluid inlet. Detailed Implementation

[0025] To make the technical problems solved, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the embodiments described herein are only some, not all, of the embodiments of this invention, and are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the protection scope of this invention.

[0026] This invention provides a kilowatt-class Hall thruster based on an ATON-type magnetic layer structure, comprising an anode, a discharge channel, and a magnetic circuit structure. The magnetic circuit structure includes inner magnetic poles, outer magnetic poles, an inner coil, an outer coil, and an auxiliary coil. A ceramic sleeve constitutes the plasma discharge region, with its lower end serving as a krypton inlet and its upper end as a krypton outlet. The anode is located inside the ceramic sleeve. This invention utilizes the auxiliary coil to construct positive and negative gradient magnetic fields and a zero-magnetic region along the central axis of the discharge channel, optimizing the magnetic field configuration. This allows the krypton ion flow to concentrate along the central axis of the channel, reducing wall collision losses and plume divergence losses, thereby improving the working fluid ionization efficiency and thruster performance, making it suitable for kilowatt-class Hall electric propulsion.

[0027] The additional coil forms a magnetic field configuration convex to the anode at the central axis of the discharge channel, including positive and negative gradient magnetic fields and a zero magnetic region, which causes the krypton working fluid ion flow to concentrate at the central axis of the channel, reducing wall collisions and plume divergence.

[0028] Understandably, the core of this invention lies in providing a Hall thruster suitable for kilowatt-level applications using krypton as the working fluid. Its most crucial technical approach is the introduction of an ATON-type magnetic layer structure. Specifically, by adding an additional coil to the inner magnetic poles, a unique magnetic field configuration is constructed within the discharge channel. This configuration includes two key features: a saddle-shaped magnetic field convex towards the anode, forming positive and negative gradient magnetic fields to achieve efficient confinement and magnetic focusing of electrons; and a zero-magnetic region located near the anode, which helps reduce anode voltage loss and makes it easier for electrons to reach the anode. This invention effectively solves the problem of insufficient ionization caused by the high ionization energy and rapid atomic movement of krypton, improving ionization efficiency, specific impulse, and thruster performance.

[0029] In some specific embodiments, the inner coil and the additional coil are provided with a radial gap from the ceramic sleeve to optimize the magnetic field distribution and prevent thermal interference.

[0030] In some specific embodiments, the ceramic sleeve is made of boron nitride ceramic material, which has good insulation and high temperature resistance.

[0031] In some specific embodiments, the anode is made of 1Cr18Ni9Ti stainless steel, the outer magnetic pole and the base plate are made of DT4C electrical pure iron, the inner magnetic pole and the auxiliary coil are made of iron-cobalt-vanadium soft magnetic alloy, and the excitation coil is made of copper wire.

[0032] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be described in further detail below.

[0033] like Figure 1 As shown, the Hall thruster of this embodiment includes an inner magnetic pole 1, an inner coil 2, a discharge channel 3, an outer magnetic pole 4, an outer coil 5, an auxiliary coil 6, a ceramic sleeve 7, an anode 8, a krypton outlet 9, and a krypton inlet 10.

[0034] Both the inner magnetic pole 1 and the outer magnetic pole 4 are made of magnetically conductive material and fixed to the base plate. The inner coil 2 and the auxiliary coil 6 are wound sequentially around the inner magnetic pole 1, and the outer coil 5 is wound around the outer magnetic pole 4. The ceramic sleeve 7 is made of boron nitride ceramic, and its interior forms an annular discharge channel 3. The anode 8 is installed at the bottom of the discharge channel 3 and is made of 1Cr18Ni9Ti stainless steel. To ensure magnetic field distribution and avoid heat exchange, radial gaps are provided between the inner coil 2 and the auxiliary coil 6 and the ceramic sleeve 7. The ceramic sleeve 7 has an L-shaped cross-section to adapt to the magnetic field configuration and optimize channel performance. The working fluid, krypton gas, enters the discharge channel 3 through the inlet 10. An external power supply powers the anode 8, cathode (not shown in the figure), and each coil. Electrons are emitted from the cathode and enter the discharge channel 3. At this time, the inner coil 2, the outer coil 5, and the crucial auxiliary coil 6 work together to form a discharge channel 3. Figure 2The special magnetic field configuration shown.

[0035] Figure 2 It is clearly shown that, under the action of the additional coil 6, a non-uniform "saddle-shaped" magnetic field convex towards the anode 8 is formed in the discharge channel 3. Near the top of the anode 8, the magnetic field strength appears in a zero magnetic region (the minimum value near the anode in this embodiment is about 25.5G), while in the middle and lower reaches of the channel, the magnetic field strength increases sharply and forms positive and negative gradients (in this embodiment, the magnetic field strength reaches a maximum of 248.4G at the magnetic extreme end face).

[0036] After entering the channel, electrons are constrained by the strong magnetic field gradient and cannot flow directly to the anode. Instead, they are forced to undergo complex Hall drift motion, which greatly prolongs their path. This process significantly increases the probability of collisions between electrons and krypton atoms, allowing even high-ionization-energy krypton atoms to achieve sufficient collisional ionization, thus realizing highly efficient ionization.

[0037] like Figure 3 As shown, the potential drop is mainly concentrated near the outlet of the discharge channel, the acceleration zone is about 0.54 dm long, and the electric field strength is the highest at the outlet.

[0038] like Figure 4 As shown, the radial component of the ion velocity reaches 23 km / s near the central axis, and the average velocity at the exit is 20 km / s, corresponding to a specific impulse of 2016 s and a thrust of 83 mN.

[0039] The krypton ions produced by ionization have a mass much larger than electrons and are almost unaffected by magnetic fields. They... Figure 3 The gas is accelerated and ejected under the influence of the axial electric field (the potential drop is mainly concentrated near the outlet). Thanks to... Figure 4 The radial ion velocity distribution shown indicates that ions are well focused near the central axis of the channel, reducing wall collisions and plume divergence.

[0040] like Figure 5 As shown, the ion number density varies significantly in the zero magnetic region along the central axis of the channel, reaching a peak of 2.5 × 10¹ after the discharge stabilizes. 8 m⁻³.

[0041] like Figure 6 As shown, ions concentrate at the outlet during the initial stage of discharge. As ionization proceeds, the ion number density reaches its peak at the inlet and outlet, and remains above 10⁻⁻⁶. 4 It stabilizes after s.

[0042] In this embodiment, under conditions of a discharge voltage of 368V, a current of 3.7A (total power 1360W), and a krypton mass flow rate of 4.2 mg / s, the thruster operates stably. Simulation and experimental results show that the average ion velocity at the exit is approximately 20 km / s, corresponding to a specific impulse as high as 2016 s, and a thrust of 83 mN. Figure 5 and Figure 6 As shown, the discharge process is stable, and the ion number density remains at a high level.

[0043] This invention addresses the unique challenges of kilowatt-level krypton Hall thrusters by achieving a technological breakthrough through the synergistic design of the "working fluid-magnetic field," and has high industrial application value.

[0044] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the nature and scope of the present invention. Various modifications made to the above embodiments by those skilled in the art after reading this specification are all within the scope of protection of the present invention.

Claims

1. A kilowatt-class Hall thruster based on an ATON-type magnetic layer structure, comprising an anode (8), a discharge channel (3), and a magnetic circuit structure, characterized in that, The magnetic circuit structure includes an inner magnetic pole (1) and an outer magnetic pole (4). The inner magnetic pole (1) is fixed on the base plate and has an inner coil (2) and an additional coil (6) wound around it. The outer magnetic pole (4) is fixed on the base plate and has an outer coil (5) wound around it. The ceramic sleeve (7) forms a plasma discharge zone, with a krypton inlet (10) at its lower end and a krypton outlet (9) at its upper end. The anode (8) is located inside the ceramic sleeve (7); The additional coil (6) is configured to form a saddle-shaped magnetic field configuration convex to the anode at the central axis of the discharge channel (3), the magnetic field configuration including a zero magnetic region formed in the anode region and positive and negative magnetic field gradient regions located on both sides of the zero magnetic region.

2. A kilowatt-class Hall thruster based on an ATON-type magnetic layer structure according to claim 1, characterized in that, The zero magnetic region is located near the top axial position of the anode (8).

3. A kilowatt-class Hall thruster based on an ATON-type magnetic layer structure according to claim 1, characterized in that, The inner magnetic pole (1), inner coil (2), auxiliary coil (6), outer magnetic pole (4), outer coil (5) and base plate are all made of magnetically conductive material.

4. A kilowatt-class Hall thruster based on an ATON-type magnetic layer structure according to claim 1, characterized in that, The anode (8) is made of 1Cr18Ni9Ti stainless steel; the outer magnetic pole (4) and the base plate are made of electrical pure iron DT4C; the inner magnetic pole (1) and the auxiliary coil (6) are made of iron-cobalt-vanadium soft magnetic alloy with high saturation magnetic induction intensity; the excitation coils of the inner coil (2), outer coil (5) and auxiliary coil (6) are made of copper wire.

5. A kilowatt-class Hall thruster based on an ATON-type magnetic layer structure according to claim 1, characterized in that, The inner coil (2), outer coil (5) and auxiliary coil (6) are made of high-temperature resistant copper wire wound on a frame and encapsulated with insulating glue; the frame is made of non-magnetic material.

6. A kilowatt-class Hall thruster based on an ATON-type magnetic layer structure according to claim 1, characterized in that, The frame is made of titanium alloy TC4.

7. A kilowatt-class Hall thruster based on an ATON-type magnetic layer structure according to claim 1, characterized in that, The inner coil (2) and the ceramic sleeve (7) are provided with a gap in the radial direction.

8. A kilowatt-class Hall thruster based on an ATON-type magnetic layer structure according to claim 1, characterized in that, The additional coil (6) and the ceramic sleeve (7) are provided with a gap in the radial direction.

9. A kilowatt-class Hall thruster based on an ATON-type magnetic layer structure according to claim 1, characterized in that, The annular channel formed by the ceramic sleeve (7) has an L-shaped cross-section.

10. A kilowatt-class Hall thruster based on an ATON-type magnetic layer structure according to claim 1, characterized in that, The Hall thruster operates under conditions of 368V discharge voltage, 1360W power, and krypton flow rate of 4.2 mg / s, and can generate at least 83mN of thrust with a specific impulse of over 2016s.

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