A dc ion thruster device based on a magnetic field configuration

Abstract

The present application relates to a kind of direct current ion thruster device based on magnetic field configuration, it relates to the field of ion thruster, including shell, tungsten filament cathode, inner magnetic ring, outer magnetic ring, upstream anode and radial anode, outer magnetic ring and inner magnetic ring are fixed to the side of discharge chamber to establish magnetic field configuration constraint plasma with magnetic field configuration;With axial gas distributor as upstream anode, radial gas distributor as radial gas supply anode, electron can move from tungsten filament cathode to upstream anode or radial gas supply anode under the action of electric field, in this process, it is captured by magnetic field configuration, further and gaseous working substance atom occurs ionization collision and generates ion;The thruster structure of the present application makes the electron distribution more uniform in discharge chamber, realizes uniform ionization to working substance gas atom in discharge chamber, and the thruster has the technical advantages of high ionization efficiency, large thrust regulation range.

Description

Technical Field

[0001] This invention relates to the field of ion thruster technology, and in particular to a DC ion thruster device based on a tangential magnetic field configuration. Background Technology

[0002] In the aerospace field, ion thrusters are currently the mainstream electric propulsion technology. A cathode is placed in the discharge chamber, and the emitted primary electrons undergo cyclotron motion under the influence of a magnetic field. Through collisional ionization, they ionize the working gas, and the resulting ions are accelerated and extracted under a strong electric field to generate thrust. Since the development of electric propulsion technology, kilowatt-class ion thrusters have gradually become the preferred solution for space missions due to their advantages such as high precision thrust adjustment, high specific impulse, and long lifespan. Currently, ion electric propulsion technology is widely used in satellite orbit changes, north-south position maintenance, and deep space exploration.

[0003] Currently, miniature DC ion thrusters have become an important technological approach for thrust control in drag-free spacecraft due to their flexible control, high specific impulse, and compact size. Kilowatt-class DC ion thrusters have an aperture of approximately 100mm–300mm, while miniature DC ion thrusters with power below 50W have an aperture of less than 30mm. Due to the reduced size, the range of electron movement is limited under magnetic field confinement, leading to a decrease in ionization rate. Simultaneously, the reduced collision frequency of electrons emitted from the cathode results in excessive consumption at the anode, increasing discharge losses. Furthermore, since miniature ion thrusters generally have lower power, the gas flow rate must be reduced. Additionally, the smaller axial dimension of the discharge channel shortens the residence time of gas within the discharge chamber, reducing the probability of collisional ionization and ultimately lowering thruster efficiency.

[0004] Furthermore, due to limited channel size, miniature ion thrusters can generally only operate efficiently under rated conditions. Since the thruster uses a single axial gas supply method, its efficiency drops significantly once the gas flow rate exceeds or falls below the rated operating condition. These problems seriously affect the normal operation of spacecraft and fail to meet the requirements of space missions for continuous thrust adjustment at the μN level in propulsion systems at relatively low power.

[0005] Therefore, to address the above shortcomings, it is necessary to provide a DC ion thruster device based on a tangential magnetic field configuration. Summary of the Invention

[0006] (a) Technical problems to be solved The technical problem to be solved by this invention is to address the low efficiency of micro ion thrusters.

[0007] (II) Technical Solution To address the aforementioned technical problems, this invention provides a DC ion thruster device based on a tangential magnetic field configuration, comprising a shell, a tungsten filament cathode, an inner magnetic ring, an outer magnetic ring, an upstream anode, and a radial anode. The tungsten filament cathode extends into the middle of the inner cavity of the shell. The tungsten filament cathode emits seed electrons required for ionization through an electrically heated method. These seed electrons gain energy in the electric field and ionize gaseous working fluid atoms in the discharge chamber. Both the inner and outer magnetic rings are fixed to a base plate. The inner diameter of the outer magnetic ring is larger than the outer diameter of the inner magnetic ring, and its axis coincides with the length direction of the tungsten filament cathode. The outer magnetic ring is fitted outside the inner magnetic ring to form a tangential magnetic field at the tungsten filament cathode to confine the ion body. The upstream anode is fixed between the inner and outer magnetic rings to introduce gaseous working fluid atoms into the tungsten filament cathode from the axial direction. The radial anode is fixed inside the shell surrounding the tungsten filament cathode and introduces gaseous working fluid atoms into the tungsten filament cathode from the radial direction. Different voltages are set for the upstream and radial anodes to adjust the energy distribution of electrons, thereby achieving uniform ionization of the gaseous working fluid atoms.

[0008] As a further explanation of the present invention, preferably, a base plate is fixedly connected to the side of the outer shell near the tungsten filament cathode. The base plate is disc-shaped to close one side of the outer shell. The tungsten filament cathode, inner magnetic ring, outer magnetic ring and upstream anode are all fixedly connected to the base plate.

[0009] As a further explanation of the present invention, preferably, a cathode ceramic is inserted between the inner magnetic ring and the tungsten wire cathode, and the cathode ceramic covers the tungsten wire cathode to insulate the inner magnetic ring and the tungsten wire cathode.

[0010] As a further explanation of the present invention, preferably, a discharge chamber ceramic is fixedly connected to the middle of the outer shell, and the inner magnetic ring and the outer magnetic ring end are covered on one side of the discharge chamber ceramic. The discharge end of the tungsten filament cathode and the gas outlet end of the upstream anode extend out of the discharge chamber ceramic. The space enclosed by the discharge chamber ceramic and the radial anode is the discharge chamber.

[0011] As a further explanation of the present invention, preferably, the radial anode has an annular structure, and the inner end face of the radial anode near the ceramic side of the discharge chamber is provided with a plurality of gas outlet holes at intervals, so that the gaseous working fluid atoms enter the discharge chamber in a vortex.

[0012] As a further explanation of the present invention, preferably, when the thrust required by the thruster is 1μN to 50μN, the gas is supplied only through the upstream anode.

[0013] As a further explanation of the present invention, preferably, when the thrust required by the thruster is 50μN to 300μN, gas is supplied simultaneously through the upstream anode and the radial anode.

[0014] As a further explanation of the present invention, preferably, an annular gate ceramic is fixedly connected to the outer side of the radial anode, a disk-shaped screen is fixedly connected to the outer side of the gate ceramic, a hole is opened in the middle of the screen, a gate ceramic ring is fixedly connected to the outer side of the screen, and an acceleration gate is fixedly connected to the outer end face of the gate ceramic ring. Positive voltage and negative voltage are applied to the screen and the acceleration gate to form an electric field to accelerate ions in the discharge chamber.

[0015] (III) Beneficial Effects The above-described technical solution of the present invention has the following advantages: 1. This invention uses permanent magnets to establish a tangential magnetic field configuration to confine plasma, which can form multi-level magnetic field tangential points in a limited space, effectively confining electron motion. Through the high-frequency collision process between electrons and atoms, the electron energy is fully applied to the ionization process of atoms, thereby improving the ionization rate of the working fluid, stabilizing the thruster discharge process, realizing the axial expansion of the ionization region, and thus improving the working efficiency of low-power thrusters.

[0016] 2. This invention uses the axial gas distributor as the upstream anode and the radial gas distributor as the radial gas supply anode, allowing electrons to move from the tungsten filament cathode to either the upstream or radial gas supply anode under the influence of an electric field. During this process, electrons are captured by the tangential magnetic field and subsequently collide with gaseous working fluid atoms to generate ions. This dual-anode structure allows for the control of the number and energy distribution of electrons moving to the upstream and radial gas supply anodes by setting different voltages, thus matching the electron distribution in the discharge chamber with the gaseous working fluid atom distribution. Ultimately, this ensures efficient ionization of gaseous working fluid atoms at all locations within the discharge chamber. Furthermore, under different gas supply flow conditions, the spatial distribution of the ionization region can be optimized by adjusting the dual-electrode voltage, thereby expanding the range of thrust discharge parameter control and achieving continuous wide-range thrust adjustment.

[0017] When the thruster operates in low thrust mode (1μN-50μN), the working fluid flow rate of the thruster is low. Therefore, the gas is injected into the discharge chamber only through the upstream anode, which allows the gas to accumulate near the axis. This matches the electron distribution that accumulates on the axis in the tangential magnetic field. In other words, high-density electrons collide with high-density atoms near the axis to ensure ionization efficiency.

[0018] When the thruster operates in high-thrust mode (50μN-300μN), the working propellant flow rate is large. If the gas flow is concentrated near the axis only upstream, the gas will quickly escape from the discharge chamber, causing a decrease in ionization rate. Simultaneously, the working propellant atoms distributed in the large-radius region of the discharge chamber have a low probability of collisional ionization due to their low electron density, making efficient ionization difficult and becoming a significant factor in the decrease in ionization efficiency. Therefore, in high-thrust mode, a dual-anode combined gas supply scheme should be adopted: part of the working propellant gas is ionized along the axis through the upstream anode, while the other part is injected into the discharge chamber through the vortex orifice of the radial gas supply anode, forming a swirling flow within the discharge chamber. This gas supply method increases the residence time of the gas in the discharge chamber, thereby increasing the ionization rate of the working propellant gas. At the same time, adjusting the operating voltage of the radial anode can guide electrons to move towards the large-radius region and change the energy distribution of electrons, thereby improving the ionization efficiency of the working propellant atoms in that region. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the cutting magnetic field of the present invention.

[0020] In the figure: 1. Outer shell; 11. Base plate; 12. Cathode ceramic; 13. Discharge chamber ceramic; 14. Grid ceramic; 15. Grid ceramic ring; 2. Tungsten filament cathode; 3. Inner magnetic ring; 4. Outer magnetic ring; 5. Upstream anode; 6. Radial anode; 7. Screen grid; 8. Acceleration grid. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] A DC ion thruster device based on a tangential magnetic field configuration, such as Figure 1As shown, the device includes a shell 1, a tungsten filament cathode 2, an inner magnetic ring 3, an outer magnetic ring 4, an upstream anode 5, and a radial anode 6. The tungsten filament cathode 2 extends into the middle of the inner cavity of the shell 1. The inner magnetic ring 3 and the outer magnetic ring 4 are both fixed to the side of the shell 1 closest to the tungsten filament cathode 2. The inner diameter of the outer magnetic ring 4 is larger than the outer diameter of the inner magnetic ring 3 and fits around the inner magnetic ring 3, with its axis coinciding with the length direction of the tungsten filament cathode 2. The upstream anode 5 is fixed between the inner magnetic ring 3 and the outer magnetic ring 4 to introduce gaseous working fluid atoms into the tungsten filament cathode 2 from the axial direction, thus stabilizing the gas supply and making the gas supply more uniform. At the same time, as the upstream anode in the dual anode configuration, it provides energy for electrons and forms a complete current loop. The radial anode 6 is fixed inside the shell 1 around the outer periphery of the tungsten filament cathode 2 and introduces gaseous working fluid atoms into the tungsten filament cathode 2 from the radial direction.

[0023] like Figure 1 As shown, the outer shell 1 is a hollow shell of revolution. A base plate 11 is fixedly connected to the side of the outer shell 1 near the tungsten filament cathode 2. The base plate 11 is disk-shaped to close one side of the outer shell 1. The tungsten filament cathode 2, inner magnetic ring 3, outer magnetic ring 4, and upstream anode 5 are all fixedly connected to the base plate 11. The tungsten filament cathode 2 emits seed electrons required for ionization by being heated by electricity. The seed electrons gain energy in the electric field formed by the tungsten filament cathode 2 and the upstream anode 5, and ionize gaseous working fluid atoms to produce ions. The inner magnetic ring 3 and the outer magnetic ring 4 form a tangential magnetic field. A cathode ceramic 12 is inserted between the inner magnetic ring 3 and the tungsten filament cathode 2. The cathode ceramic 12 covers the tungsten filament cathode 2 to insulate the inner magnetic ring 3 and the tungsten filament cathode 2. A discharge chamber ceramic 13 is fixedly connected to the center of the outer shell 1. One side of the discharge chamber ceramic 13 covers the ends of the inner magnetic ring 3 and the outer magnetic ring 4. The discharge end of the tungsten filament cathode 2 and the outlet end of the upstream anode 5 extend outside the discharge chamber ceramic 13. The space enclosed by the discharge chamber ceramic 13 and the radial anode 6 forms the discharge chamber. The outer magnetic ring 4 and the inner magnetic ring 3 are fixed to the side of the discharge chamber to establish a tangential magnetic field configuration to confine the plasma. This magnetic field configuration can form multiple levels of magnetic field tangency points within a limited space, effectively confining electron movement and allowing more electrons to deposit in the plasma within the discharge chamber. This improves the ionization rate, stabilizes the discharge process, and achieves axial expansion of the ionization region, thereby enhancing ionization efficiency.

[0024] like Figure 1As shown, the radial anode 6 has a ring-shaped structure. Several gas outlet holes are spaced apart on the inner end face of the radial anode 6 near the ceramic side of the discharge chamber to achieve radial vortex gas supply and simultaneously provide energy for electrons. By using the axial gas distributor as the upstream anode 5 and the radial gas distributor as the radial anode 6, electrons can move from the tungsten filament cathode to either the upstream anode 5 or the radial anode 6 under the influence of an electric field. During this process, they are captured by the tangential magnetic field and subsequently collide with gaseous working fluid atoms to generate ions. This dual-anode structure allows for adjustment of the electron energy distribution by setting different voltages, thereby controlling the number of electrons moving to the inner and outer anodes respectively. This makes the electron distribution in the discharge chamber match the gaseous working fluid atom distribution, resulting in a more uniform electron distribution and ultimately achieving uniform ionization of gaseous working fluid atoms at all locations within the discharge chamber.

[0025] By supplying gas to the upstream anode 5 as an axial gas distributor and the radial anode 6 as a radial gas distributor, the spatial distribution of the ionization region can be optimized by adjusting the dual-electrode voltage under different gas supply flow conditions. This expands the range of thrust discharge parameter control and enables continuous wide-range thrust adjustment. Specifically: 1. Low-thrust mode: When the thruster operates at a thrust of 1μN-50μN, the working fluid flow rate is low, so gas is supplied only through the upstream anode 5. At this time, the direction of the gaseous working fluid atoms entering the discharge chamber is almost perpendicular to the magnetic field lines, which allows the gas to accumulate near the axis. This matches the distribution of the pads that accumulate on the axis in the tangential magnetic field, and the electrons are in a state of enveloping the gas flow. This allows the high-density electrons near the axis to collide with the high-density gaseous working fluid atoms, thus ensuring ionization efficiency while achieving low thrust.

[0026] 2. High-Thrust Mode: When the thruster operates at 50μN-300μN, the working fluid flow rate is relatively high. If only the upstream anode 5 is used for axial gas supply, the gas will quickly escape from the discharge chamber, leading to a decrease in ionization rate. Simultaneously, the gaseous working fluid atoms distributed in the large-radius region within the discharge chamber have a low probability of collisional ionization due to their low electron density, making efficient ionization difficult and becoming a significant factor in the decrease in ionization efficiency. Therefore, in high-thrust mode, in addition to axial gas supply via the upstream anode 5, radial vortex gas supply is also used via the radial anode 6, forming a swirling flow within the discharge chamber. This gas supply method increases the residence time of the gas within the discharge chamber, thereby increasing the ionization rate of the gaseous working fluid atoms. Simultaneously, increasing the operating voltage of the radial gas supply anode 6 guides electrons to move towards the large-radius region and alters the electron energy distribution, thereby improving the ionization efficiency of the working fluid atoms in that region.

[0027] like Figure 1As shown, an annular gate ceramic 14 is fixed to the outer side of the radial anode 6, and a disc-shaped screen 7 is fixed to the outer side of the gate ceramic 14. A hole is opened in the middle of the screen 7, and a gate ceramic ring 15 is fixed to the outer side of the screen 7. An acceleration gate 8 is fixed to the outer end face of the gate ceramic ring 15. The screen 7 and the acceleration gate 8 are fixed to the gate ceramic 14 by bolts. By applying high positive voltage and high negative voltage respectively, a huge electric field is formed to accelerate the ions generated in the discharge chamber, and finally generate thrust. The gate ceramic ring 15 is fixed between the screen 7 and the acceleration gate 8 by bolts to play an insulating role.

[0028] The present invention also provides a method for operating a DC ion thruster device based on a tangential magnetic field configuration, comprising the following steps: I. Gaseous working fluid atoms are introduced into the upstream anode 5 and the radial anode 6. After passing through the gas distributor, the working fluid atoms enter the discharge chamber evenly.

[0029] II. Connect the cathode and anode to the positive and negative terminals of the power supply, respectively. The tungsten filament cathode 2 emits primary electrons that move towards the anode under the influence of the potential difference between the cathode and the anode. During the movement, the electrons collide with the working medium atoms and ionize, producing ions and secondary electrons. The secondary electrons are also accelerated by the cathode and anode to obtain enough energy to ionize the working medium atoms and produce ions.

[0030] III. The tangential magnetic field generated by the inner and outer magnetic rings on the side of the discharge chamber forms a multi-level magnetic field tangency point within the limited space, effectively confining the movement of electrons, prolonging their residence time in the discharge chamber, improving the ionization efficiency of electrons, and finally, the electrons move to the anode and are absorbed.

[0031] IV. Apply a positive voltage of hundreds of volts to the screen grid 7 and a negative voltage of hundreds of volts to the acceleration grid 8; the ions generated by ionization in the discharge chamber are accelerated and extracted under the potential difference formed by the screen grid 7 and the acceleration grid 8 to generate thrust.

[0032] In summary, this invention employs a dual-anode structure, utilizing both upstream anode 5 for axial gas supply and radial anode 6 for radial gas supply. This not only ensures the required gas ionization rate in the discharge chamber during continuous variable thrust adjustment but also allows for more uniform electron distribution within the discharge chamber by setting different voltages. Ultimately, this results in uniform ionization of gaseous working fluid atoms at all locations within the discharge chamber and enables axial expansion of the ionization region, thereby improving ionization efficiency. Furthermore, optimizing the spatial layout of the electrodes within the tangential magnetic field reduces ion loss, thus extending the service life.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A DC ion thruster device based on a tangential magnetic field configuration, characterized in that: The system includes an outer shell (1), a tungsten filament cathode (2), an inner magnetic ring (3), an outer magnetic ring (4), an upstream anode (5), and a radial anode (6). The tungsten filament cathode (2) extends into the middle of the inner cavity of the outer shell (1). The tungsten filament cathode (2) emits seed electrons required for ionization by means of electric heating. The seed electrons gain energy in the electric field and ionize the gaseous working substance atoms in the discharge chamber. The inner magnetic ring (3) and the outer magnetic ring (4) are both fixed on the base plate (11). The inner diameter of the outer magnetic ring (4) is larger than the outer diameter of the inner magnetic ring (3), and its axis coincides with the length direction of the tungsten filament cathode (2). The outer magnetic ring (4) is fitted outside the inner magnetic ring (3) to form a tangential magnetic field at the tungsten filament cathode (2) to confine the ion body. The upstream anode (5) is fixed between the inner magnetic ring (3) and the outer magnetic ring (4) to introduce gaseous working substance atoms into the tungsten filament cathode (2) from the axial direction. The radial anode (6) is fixed to the tungsten filament cathode (2). Gaseous working medium atoms are introduced into the outer shell (1) of the cathode (2) from the radial direction to the tungsten wire cathode (2); the radial anode (6) is a ring structure, and several gas outlet holes are spaced apart on the inner end face of the radial anode (6) so that the gaseous working medium atoms enter the discharge chamber in a vortex; a ring-shaped grid ceramic (14) is fixed to the outer side of the radial anode (6), a disk-shaped screen grid (7) is fixed to the outer side of the grid ceramic (14), a hole is opened in the middle of the screen grid (7), a grid ceramic ring (15) is fixed to the outer side of the screen grid (7), and an acceleration grid (8) is fixed to the outer end face of the grid ceramic ring (15). Positive voltage and negative voltage are applied to the screen grid (7) and the acceleration grid (8) to form an electric field to accelerate the ions in the discharge chamber; the upstream anode (5) and the radial anode (6) are set with different voltages to adjust the energy distribution of electrons, so that the gaseous working medium atoms can be uniformly ionized.

2. The DC ion thruster device based on a tangential magnetic field configuration according to claim 1, characterized in that: The outer shell (1) is fixed to a base plate (11) on the side near the tungsten filament cathode (2). The base plate (11) is disc-shaped so that the outer shell (1) is closed on one side. The tungsten filament cathode (2), inner magnetic ring (3), outer magnetic ring (4) and upstream anode (5) are all fixed to the base plate (11).

3. The DC ion thruster device based on a tangential magnetic field configuration according to claim 2, characterized in that: A cathode ceramic (12) is inserted between the inner magnetic ring (3) and the tungsten wire cathode (2). The cathode ceramic (12) covers the tungsten wire cathode (2) to insulate the inner magnetic ring (3) and the tungsten wire cathode (2).

4. The DC ion thruster device based on a tangential magnetic field configuration according to claim 3, characterized in that: The inner middle of the outer shell (1) is fixed with a discharge chamber ceramic (13). The inner magnetic ring (3) and the outer magnetic ring (4) are covered on one side of the discharge chamber ceramic (13). The discharge end of the tungsten wire cathode (2) and the gas outlet end of the upstream anode (5) extend out of the discharge chamber ceramic (13). The space enclosed by the discharge chamber ceramic (13) and the radial anode (6) is the discharge chamber.

5. A DC ion thruster device based on a tangential magnetic field configuration according to claim 4, characterized in that: When the thrust required by the thruster is 1μN to 50μN, the gas is supplied only through the upstream anode (5).

6. A DC ion thruster device based on a tangential magnetic field configuration according to claim 5, characterized in that: When the thrust required by the thruster is 50μN to 300μN, gas is supplied through the upstream anode (5) and the radial anode (6).

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