Kaufman ion thruster with thrust quantitatively controllable and self-neutralizing and application method thereof

Abstract

The present application relates to the technical field of spacecraft space electric propulsion, and discloses a thrust quantitatively controllable and self-neutralizable Kaufman ion thruster and a method for using the same, comprising a discharge chamber, a center cathode, a gas supply assembly, a steel magnetic assembly, an insulating partition and a grid system; the center cathode is coaxially inserted into the center of the front panel; the gas supply assembly comprises an electronegative working medium gas source, a conventional working medium gas source, N electronegative working medium gas supply pipes and N working medium gas supply pipes; the insulating partition comprises a center connecting rod and 2N fins; the 2N fins divide the discharge chamber into 2N discharge areas; and the grid system comprises a bias power supply and 2N sector-shaped grids. The present application improves the thrust structure of the Kaufman ion thruster, so that self-neutralization can be achieved without a neutralizer. In addition, the present application has N on-center thrust modes and N-1 eccentric thrust modes; the on-center thrust modes can be used for spacecraft orbit control; and the eccentric thrust modes can be used for spacecraft attitude adjustment.

Description

Technical Field

[0001] The present invention relates to the field of spacecraft electric propulsion technology, in particular to a Kaufman ion thruster with quantitatively controllable and self-neutralizing thrust and an application method thereof. Background Art

[0002] Currently, ion thrusters play an important role in spacecraft attitude and orbit control due to their advantages of low thrust, high specific impulse, and long life. Among them, the Kaufman electric thruster is the most widely used ion thruster.

[0003] However, the existing Kaufman ion thruster still has the following three problems in use that need to be improved:

[0004] The Kaufman ion thruster consists of a main cathode, gas supply tube, discharge chamber, grid, and neutralizer. A separate neutralizer located near the grid emits electrons to neutralize the ion beam drawn from the grid. This prevents positively charged ions from adhering to the spacecraft, potentially causing an electrical potential imbalance and impacting normal operation. However, the presence of the neutralizer increases the overall system complexity, increasing structural size and deteriorating symmetry. Furthermore, its energy consumption and ablation issues significantly impact the reliability and lifespan of the entire propulsion system.

[0005] 2. Kaufman ion thrusters primarily achieve thrust changes by regulating the working fluid flow rate. However, changes in flow rate can affect the characteristics of plasma generation and ion beam extraction in the discharge chamber, resulting in a non-proportional relationship between flow rate and thrust. This makes precise control of thrust by varying flow rate difficult. Space missions such as gravitational wave detection and high-resolution Earth observation require extremely high-precision thruster adjustment. Solving this precise thrust control for Kaufman ion thrusters is crucial for precise attitude and orbit control of these spacecraft.

[0006] 3. For future deep space exploration, it is necessary to develop high-thrust electric propulsion devices. However, the Kaufman ion thruster is limited by the rigidity of the grid elements of the ion optical system, and its size cannot be very large, which in turn affects the development of large-caliber thrusters, making it difficult to significantly increase the thrust. Summary of the Invention

[0007] The present invention addresses the shortcomings of the prior art by providing a Kaufman ion thruster with controllable and self-neutralizing thrust and its application method. This device and its application method eliminate the need for a neutralizer, achieving self-neutralization and thus addressing the increased structural complexity associated with a neutralizer. Furthermore, it features a centripetal thrust mode for orbit control and an eccentric thrust mode for attitude adjustment.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A Kaufman ion thruster with controllable thrust quantity and self-neutralization comprises a discharge chamber, a central cathode, a gas supply assembly, a steel magnetic assembly, an insulating partition and a grid system.

[0010] The tail end of the discharge chamber is open, and the front end is provided with a front panel.

[0011] The center cathode is coaxially inserted in the center of the front panel.

[0012] The gas supply assembly includes N electronegative working fluid gas supply pipes and N working fluid gas supply pipes; wherein N≥2.

[0013] N electronegative working fluid gas supply pipes and N working fluid gas supply pipes are evenly and staggeredly arranged on the front panel of the central cathode periphery;

[0014] The steel magnetic assembly is used to form an annular cusp field in the discharge chamber.

[0015] The insulating partition includes a central connecting rod and 2N fins; the central connecting rod is coaxially inserted in the discharge chamber, and the 2N fins are evenly distributed along the circumference of the central connecting rod and divide the discharge chamber into 2N discharge areas; an axial discharge gap is formed between the upstream ends of the 2N fins and the tail end of the central cathode; and the tail ends of the 2N fins extend from the tail end of the discharge chamber.

[0016] The 2N discharge regions correspond one-to-one to the N electronegative working fluid gas supply pipes and the N working fluid gas supply pipes, wherein the discharge region corresponding to the N electronegative working fluid gas supply pipes is called a negative discharge region, and the discharge region corresponding to the N working fluid gas supply pipes is called a positive discharge region; the N electronegative working fluid gas supply pipes are used to supply electronegative working fluid gas 1 to the N negative discharge regions, and the N working fluid gas supply pipes are used to supply electronegative working fluid gas 2 or non-electronegative working fluid gas to the N positive discharge regions; the electronegativity of the electronegative working fluid gas 2 is less than that of the electronegative working fluid gas 1.

[0017] The gate system includes a bias power supply and 2N sector-shaped gates connected to the bias power supply. The 2N sector-shaped gates are arranged at the tail ends of the 2N discharge areas. Among them, the sector-shaped gates corresponding to the negative discharge area are called negative sector-shaped gates, and the sector-shaped gates corresponding to the positive discharge area are called positive sector-shaped gates. The bias power supply can apply a positive bias to each negative sector-shaped gate and a negative bias to each positive sector-shaped gate.

[0018] The gas supply component also includes an electronegative working fluid gas source and a conventional working fluid gas source.

[0019] The electronegative working gas source is filled with electronegative working gas 1; the conventional working gas source is filled with electronegative working gas 2 or non-electronegative working gas.

[0020] Each electronegative working fluid gas supply pipe is connected to an electronegative working fluid gas source through valve one; each working fluid gas supply pipe is connected to a conventional working fluid gas source through valve two.

[0021] N=3 or 4.

[0022] The discharge chamber comprises a small cylindrical chamber, a transition frustum chamber and a large cylindrical chamber which are sequentially arranged along the axial direction; the outer diameter of the small cylindrical chamber is smaller than the outer diameter of the large cylindrical chamber.

[0023] The 2N fins are all located in the transition cone chamber and the large cylindrical chamber, and the outer end of each fin is sealed and connected to the inner wall of the transition cone chamber and the large cylindrical chamber; the tail end of the central cathode is located in the small cylindrical chamber.

[0024] The tail ends of the N electronegative working fluid supply pipes all pass through the small cylindrical chamber and then extend into the N negative discharge areas; the tail ends of the N working fluid supply pipes all pass through the small cylindrical chamber and then extend into the N positive discharge areas.

[0025] The steel magnetic assembly includes cathode end magnets, column segment magnets and gate end magnets; the cathode end magnets are coaxially arranged in the shell of the small cylindrical chamber on the outer periphery of the central cathode; the column segment magnets are coaxially embedded in the upstream end of the large cylindrical chamber shell, and the gate end magnets are coaxially embedded in the downstream end of the large cylindrical chamber shell and adjacent to the sector-shaped gate.

[0026] The utility model also comprises a magnetic filtering device, which is coaxially sleeved on the middle outer periphery of the large cylindrical chamber.

[0027] Each sector grid comprises a sector screen grid and an accelerating sector grid which are arranged in parallel in sequence along the axial direction; an insulating mica sheet is arranged between the outer edge of the sector screen grid and the outer edge of the accelerating sector grid.

[0028] A method for operating a Kaufman ion thruster with quantitatively controllable and self-neutralizing thrust can achieve orbit control and attitude adjustment of the Kaufman ion thruster by controlling N electronegative working fluid supply pipes and the gas supply start timing of the N working fluid supply pipes.

[0029] The orbit control method of the Kaufman ion thruster comprises the following steps:

[0030] Step 1-1, combining symmetrical discharge regions: a positive discharge region and a negative discharge region that are symmetrical about the axis of the discharge chamber are called a group of symmetrical discharge regions; an electronegative working fluid gas supply pipe and a working fluid gas supply pipe corresponding to each group of symmetrical discharge regions form a group of symmetrical gas supply pipes; a positive sector-shaped grid and a negative sector-shaped grid corresponding to each group of symmetrical discharge regions form a group of symmetrical grids; thus, the discharge chamber has N groups of symmetrical discharge regions, the gas supply assembly has N groups of symmetrical gas supply pipes; and the grid system has N groups of symmetrical grids.

[0031] Step 1-2: Select the number of starting groups of the symmetrical air supply pipes: Select the number K of starting groups of the symmetrical air supply pipes based on the total thrust F required for orbit control of the Kaufman ion thruster; wherein the number K of starting groups is proportional to the total thrust F, and 1≤K≤N.

[0032] Step 1-3, start gas supply: synchronously start the K groups of symmetrical gas supply pipes selected in step 1-2; each group of symmetrical gas supply pipes supplies gas to the corresponding positive discharge area or negative discharge area according to the same set fixed flow rate; among them, the electronegative working fluid gas supply pipe in the symmetrical gas supply pipe will supply electronegative working fluid gas 1 to the corresponding negative discharge area, and the working fluid gas supply pipe in the symmetrical gas supply pipe will supply electronegative working fluid gas 2 or non-electronegative working fluid gas to the corresponding positive discharge area.

[0033] Step 1-4, start K groups of symmetrical grids: while starting the gas supply in step 1-3, the bias power supply in the grid system will apply a bias to the K groups of symmetrical grids; wherein the K groups of symmetrical grids correspond to the axial position of the K groups of symmetrical gas supply pipes selected in step 1-2; the bias power supply applies a positive bias to each negative sector-shaped grid in the K groups of symmetrical grids, and applies a negative bias to each positive sector-shaped grid in the K groups of symmetrical grids.

[0034] Step 1-5, plasma formation: The central cathode starts emitting primary electrons, which uniformly enter 2N discharge regions. The primary electrons entering the K symmetrical discharge regions collide with the working fluid gas supplied by the symmetrical gas supply pipe to generate plasma. The primary electrons collide with the electronegative working fluid gas 1 supplied by the electronegative working fluid supply pipe to generate "electron-ion" plasma, and an "ion-ion" plasma containing positive and negative ions is generated downstream of the negative discharge region. The primary electrons collide with the electronegative working fluid gas 2 or the non-electronegative working fluid gas supplied by the working fluid supply pipe to generate "electron-ion" plasma, and an "ion-ion" plasma containing positive and negative ions is generated downstream of the positive discharge region. The negative ion density in the "ion-ion" plasma downstream of the negative discharge region is greater than the negative ion density in the "ion-ion" plasma downstream of the positive discharge region. The K symmetrical discharge regions correspond to the axial positions of the K symmetrical gas supply pipes selected in step 1-2. The primary electrons entering the remaining NK symmetrical discharge regions are collected by the walls of the corresponding discharge regions.

[0035] Step 1-6, extracting and accelerating plasma: The negative sector-shaped grid in the K group of symmetrical grids will extract and accelerate the negative ions in the plasma ejected from the tail end of the negative discharge region. The accelerated negative ions will generate a partial thrust F1 for the Kaufman ion thruster; the positive sector-shaped grid in the K group of symmetrical grids will extract and accelerate the positive ions in the plasma ejected from the tail end of the positive discharge region. The accelerated positive ions will generate a partial thrust F2 for the Kaufman ion thruster.

[0036] Step 1-7, Ion beam neutralization: The negative ions and positive ions accelerated by each set of symmetric grid are self-neutralized.

[0037] Step 1-8, Orbit control: At the same time of ion beam neutralization, the sum of all partial thrusts F1 and F2 will form the axial total thrust F of the center of mass of the Kaufman ion thruster, which can be used for orbit control.

[0038] The attitude adjustment method of the Kaufman ion thruster comprises the following steps.

[0039] Step 2-1, Combination of eccentric discharge area: the adjacent one positive discharge area and one negative discharge area are referred to as one set of eccentric discharge area; thus, 2N discharge areas are formed into the 1st, 2nd, 3rd, …, N-1th set of eccentric discharge area in clockwise or counterclockwise direction; one electrically negative working gas supply pipe and one working gas supply pipe corresponding to each set of eccentric discharge area are referred to as one set of eccentric gas supply pipe; the positive sector grid and the negative sector grid corresponding to each set of eccentric discharge area are referred to as one set of eccentric grid.

[0040] Step 2-2, Selection of J sets of eccentric gas supply pipe: according to the current attitude and the adjusted attitude of the Kaufman ion thruster, the rotational thrust moment M required for attitude adjustment is calculated, and then the start-up number J of sets of eccentric gas supply pipe and the circumferential position of J sets of eccentric gas supply pipe are selected; wherein, 1≤J≤N-1; the eccentric discharge area corresponding to the axial position of J sets of eccentric gas supply pipe is referred to as J sets of eccentric discharge area; the eccentric grid corresponding to the axial position of J sets of eccentric gas supply pipe is referred to as J sets of eccentric grid.

[0041] Step 2-3, Start-up of gas supply: J sets of eccentric gas supply pipe selected in step 2-2 are started up synchronously; each set of eccentric gas supply pipe supplies gas to the corresponding positive discharge area or negative discharge area according to the set fixed flow rate; wherein, the electrically negative working gas supply pipe in the eccentric gas supply pipe supplies the electrically negative working gas one to the corresponding negative discharge area, and the working gas supply pipe in the eccentric gas supply pipe supplies the electrically negative working gas two or the non-electrically negative working gas to the corresponding positive discharge area.

[0042] Step 2-4, Start-up of J sets of eccentric grid: at the same time of starting up the gas supply in step 1-3, the bias power supply in the grid system applies a bias voltage to J sets of eccentric grid; the bias power supply applies a positive bias voltage to each negative sector grid in J sets of eccentric grid, and applies a negative bias voltage to each positive sector grid in J sets of eccentric grid.

[0043] Step 2-5, plasma formation: The central cathode starts emitting primary electrons, which uniformly enter the 2N discharge regions. The primary electrons entering the J groups of eccentric discharge regions collide with the working fluid gas supplied by the eccentric gas supply pipe to generate plasma. The primary electrons collide with the electronegative working fluid gas 1 supplied by the electronegative working fluid supply pipe to generate "electron-ion" plasma, and "ion-ion" plasma containing positive and negative ions is generated downstream of the negative discharge region. The primary electrons collide with the electronegative working fluid gas 2 or the non-electronegative working fluid gas supplied by the working fluid supply pipe to generate "electron-ion" plasma, and "ion-ion" plasma containing positive and negative ions is generated downstream of the positive discharge region. The negative ion density in the "ion-ion" plasma downstream of the negative discharge region is greater than the negative ion density in the "ion-ion" plasma downstream of the positive discharge region. The primary electrons entering the remaining NJ groups of eccentric discharge regions will be collected by the walls of the corresponding discharge regions.

[0044] Step 2-6, extracting and accelerating plasma: The negative sector-shaped grids in the J group of eccentric grids will extract and accelerate the negative ions in the plasma ejected from the tail end of the negative discharge region. The accelerated negative ions will generate a partial thrust F1' for the Kaufman ion thruster; the positive sector-shaped grids in the J group of eccentric grids will extract and accelerate the positive ions in the plasma ejected from the tail end of the positive discharge region. The accelerated positive ions will generate a partial thrust F2' for the Kaufman ion thruster.

[0045] Step 2-7, ion beam neutralization: negative ions and positive ions accelerated by each set of eccentric grids are self-neutralized.

[0046] Step 2-8, attitude adjustment: While the ion beam is being neutralized, the sum of all partial thrusts F1' and F2' will generate a rotational thrust torque M on the center of mass of the Kaufman ion thruster, thereby achieving attitude adjustment of the Kaufman ion thruster.

[0047] The present invention has the following beneficial effects:

[0048] 1. The present invention does not require a neutralizer and can achieve self-neutralization, thereby solving the problem of increased structural complexity caused by the neutralizer.

[0049] 2. The present invention has both centripetal and eccentric thrust modes. The centripetal thrust mode can be used for orbit control, while the eccentric thrust mode can be used for attitude adjustment. Therefore, the ability to precisely control the thrust of the Kaufman ion thruster is of great significance for its application in precise attitude and orbit control of such spacecraft.

[0050] 3. The present invention has N centripetal thrust modes and N-1 eccentric thrust modes. Each mode has a different thrust. By switching between modes, the thrust of the Kaufman ion thruster can be adjusted. In each mode, the working gas flow rate in each gas supply pipe remains unchanged. In other words, the thrust of the Kaufman ion thruster is independent of changes in the working gas flow rate, and thus does not affect the plasma characteristics of the discharge chamber and the ion beam extraction characteristics. Therefore, the thrust control is precise and can be adapted to space missions such as gravitational wave detection and high-resolution Earth observation.

[0051] 4. Each sector-shaped grid in the present invention is small in size, so it can ensure increased rigidity, thereby being able to adapt to large-sized discharge chambers and to conduct research on large-caliber thrusters, thereby significantly improving thrust, thereby being able to adapt to the research on large-thrust electric propulsion devices required for future deep space exploration. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The overall structure of the Kaufman ion thruster with quantitatively controllable and self-neutralizing thrust is shown in the present invention. Figure 1 .

[0053] Figure 2 An axial cross-sectional view of a Kaufman ion thruster with quantitatively controllable thrust and self-neutralization according to the present invention is shown.

[0054] Figure 3 The overall structure of the Kaufman ion thruster with quantitatively controllable and self-neutralizing thrust is shown in the present invention. Figure 2 .

[0055] Figure 4 A schematic diagram showing the division of the discharge chamber and the grid area in the present invention is shown.

[0056] Among them are:

[0057] 1. Discharge chamber; 2. Gas supply pipe; 3. Central cathode; 4. Cathode end magnet; 5. Column segment magnet; 6. Grid end magnet; 7. Magnetic filter; 8. Insulating partition; 9. Accelerating sector grid; 10. Sector screen grid; 11. Insulating mica sheet. Implementation Method

[0058] The present invention will be further described in detail below with reference to the accompanying drawings and specific preferred embodiments.

[0059] In the description of the present invention, it should be understood that the terms "left side," "right side," "upper," "lower," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Terms such as "first" and "second" do not indicate the importance of components and therefore should not be construed as limitations on the present invention. The specific dimensions used in this embodiment are intended only to illustrate the technical solution and do not limit the scope of protection of the present invention.

[0060] like Figures 1 to 3 As shown, a Kaufman ion thruster with quantitatively controllable thrust and self-neutralization includes a discharge chamber 1, a central cathode 3, an air supply assembly, a steel magnetic assembly, a magnetic filter device 7, an insulating partition 8 and a grid system.

[0061] The discharge chamber 1 is open at its rear end and has a front panel at its front end. In this embodiment, the discharge chamber 1 preferably comprises a small cylindrical chamber, a transitional frustum chamber, and a large cylindrical chamber arranged in sequence along the axial direction; the outer diameter of the small cylindrical chamber is smaller than that of the large cylindrical chamber. Alternatively, the discharge chamber 1 may have other known shapes.

[0062] The central cathode 3 is coaxially inserted in the center of the front panel and can emit primary electrons to the discharge chamber 1. The tail end of the central cathode 3 is preferably located in the small cylindrical chamber.

[0063] The gas supply assembly includes a gas source and 2N gas supply tubes 2. These 2N gas supply tubes 2 are evenly distributed on the front panel around the central cathode 3. N ≥ 2, with N preferably being 3 or 4. A value too small limits the thrust adjustment options and may even prevent the generation of eccentric torque. A value too large complicates manufacturing and overcomplicates the Kaufman ion thruster structure. This embodiment uses N = 3 as an example for detailed description.

[0064] The gas source includes an electronegative working fluid gas source and a conventional working fluid gas source.

[0065] The 2N gas supply pipes 2 include N electronegative working fluid gas supply pipes and N working fluid gas supply pipes that are staggered along the circumferential direction.

[0066] The electronegative working gas source is filled with electronegative working gas 1, and the conventional working gas source is filled with electronegative working gas 2 or non-electronegative working gas. The electronegativity of electronegative working gas 2 is less than that of electronegative working gas 1.

[0067] The electronegativity mentioned above is the property that molecules easily absorb free electrons to form negative ions. Electronegative gas refers to a gas that has a significant ability to capture free electrons to form negative ions and prevent the formation of discharge.

[0068] Each electronegative working fluid gas supply pipe is preferably connected to an electronegative working fluid gas source through a valve 1; the electronegative working fluid gas source can provide electronegative working fluid gas 1, such as SF6, I2, C 60 or C 78 In this embodiment, C 60 , which is a gas at high temperature or low temperature and low pressure.

[0069] Each working fluid gas supply pipe is preferably connected to a conventional working fluid gas source through valve 2. The conventional working fluid gas source can provide electronegative working fluid gas 2 or non-electronegative working fluid gas, such as xenon gas Xe and krypton gas Kr, to the N working fluid gas supply pipes.

[0070] The above-mentioned steel magnetic assembly is used to form an annular cusp field in the discharge chamber 1, and preferably includes a cathode end magnet 4, a column segment magnet 5 and a grid end magnet 6; the cathode end magnet 4 is coaxially arranged in the shell of the small cylindrical chamber on the outer periphery of the central cathode 3; the column segment magnet 5 is coaxially embedded in the upstream end of the large cylindrical chamber shell, and the grid end magnet 6 is coaxially embedded in the downstream end of the large cylindrical chamber shell and adjacent to the sector-shaped grid.

[0071] The magnetic filter device 7 is coaxially mounted on the outer periphery of the middle portion of the large cylindrical chamber, preferably located on the outer periphery of the shell of the large cylindrical chamber between the column segment magnetic steel 5 and the grid end magnetic steel 6. The magnetic filter device 7 can confine electrons in the plasma upstream of the discharge chamber 1.

[0072] The insulating partition 8 is preferably made of ceramic material and includes a central connecting rod and 2N fins.

[0073] The central connecting rod is coaxially inserted in the discharge chamber 1, preferably inserted in the transition cone chamber and the large cylindrical chamber, and an axial gap is preferably provided between the upstream end of the central connecting rod and the tail end of the central cathode 3.

[0074] 2N fins are evenly arranged along the circumference of the central connecting rod and divide the discharge chamber 1 into 2N discharge zones. The 2N discharge zones correspond one-to-one to the N electronegative working fluid supply pipes and the N working fluid supply pipes. The discharge zone corresponding to the N electronegative working fluid supply pipes is called a negative discharge zone, and the discharge zone corresponding to the N working fluid supply pipes is called a positive discharge zone.

[0075] like Figure 4 As shown in the figure, the six discharge areas (taking N=3 as an example) are A, B, C, D, E and F arranged counterclockwise. Among them, A, C and E are positive discharge areas; B, D and F are negative discharge areas.

[0076] The tail ends of the N electronegative working fluid gas supply pipes pass through the small cylindrical chamber and extend into the N negative discharge areas, so as to supply electronegative working fluid gas 1 to the N negative discharge areas.

[0077] The N working substance supply pipes all extend into the N positive discharge zones after penetrating the small cylindrical chamber, and are used for supplying the electronegative working substance gas or the non-electronegative working substance gas to the N positive discharge zones.

[0078] The 2N fins are located in the transition circular table chamber and the large cylindrical chamber, and the upstream ends of the 2N fins are all provided with an axial discharge gap between the center cathode 3 tail end; the outer ends of the 2N fins are all in sealing connection with the inner side walls of the transition circular table chamber and the large cylindrical chamber; the tail ends of the 2N fins all extend out of the discharge chamber 1 tail end, and are used for installing the subsequent fan-shaped grids.

[0079] The grid system comprises a bias power supply and 2N fan-shaped grids connected with the bias power supply, the 2N fan-shaped grids are arranged at the tail ends of the 2N discharge zones, and are installed on the adjacent two fins. Among them, the fan-shaped grid corresponding to the negative discharge zone is called a negative fan-shaped grid, and the fan-shaped grid corresponding to the positive discharge zone is called a positive fan-shaped grid; the bias power supply can apply a positive bias to each negative fan-shaped grid, and can also apply a negative bias to each positive fan-shaped grid.

[0080] Each fan-shaped grid comprises a fan-shaped screen grid 10 and an acceleration fan-shaped grid 9 arranged in parallel along the axial direction in sequence; an insulating mica sheet 11 or other ceramic high-temperature-resistant insulating medium is arranged between the outer edge of the fan-shaped screen grid 10 and the outer edge of the acceleration fan-shaped grid 9.

[0081] A running method of a thrust quantitatively controllable and self-neutralized Kaufman ion thruster, by controlling the gas supply starting time of the N electronegative working substance supply pipes and the N working substance supply pipes, the orbit control and attitude adjustment of the Kaufman ion thruster can be realized.

[0082] A, the concentric thrust mode - orbit control

[0083] The orbit control method of the above-mentioned Kaufman ion thruster preferably comprises the following steps:

[0084] Step 1-1, combination of symmetrical discharge zones: one positive discharge zone and one negative discharge zone symmetrical about the axis of the discharge chamber 1 are called a set of symmetrical discharge zones; one electronegative working substance supply pipe and one working substance supply pipe corresponding to each set of symmetrical discharge zones form a set of symmetrical supply pipes; a positive fan-shaped grid and a negative fan-shaped grid corresponding to each set of symmetrical discharge zones form a set of symmetrical grids; thus, the discharge chamber 1 has N sets of symmetrical discharge zones, the gas supply assembly has N sets of symmetrical supply pipes; the grid system has N sets of symmetrical grids.

[0085] In this embodiment, the N sets of symmetrical supply pipes correspond to N concentric thrust modes.

[0086] Step 1-2: Select the number of symmetrical gas supply tube activation groups: Select the number K of symmetrical gas supply tube activation groups based on the total thrust F required for orbital control of the Kaufman ion thruster. The number K is proportional to the total thrust F, and 1 ≤ K ≤ N. This embodiment uses K = 1, i.e., the minimum total thrust F, as an example for detailed description.

[0087] Step 1-3, start gas supply: synchronously start the K groups of symmetrical gas supply pipes selected in step 1-2. In this embodiment, starting the symmetrical gas supply pipes corresponding to the positive discharge area A and the negative discharge area D is taken as an example for detailed description.

[0088] Each set of symmetrical gas supply pipes supplies gas to the corresponding positive discharge area or negative discharge area according to the same fixed flow rate; wherein the electronegative working fluid gas supply pipe in the symmetrical gas supply pipe preferably supplies electronegative working fluid gas C to the corresponding negative discharge area. 60 The working fluid supply pipes in the symmetrical gas supply pipes preferably supply the working fluid Xe to the corresponding positive discharge region. The electronegative working fluid supply pipes in each group of symmetrical gas supply pipes have different fixed flow rates, while all electronegative working fluid supply pipes have the same fixed flow rate.

[0089] Step 1-4, start K groups of symmetrical grids: while starting the gas supply in step 1-3, the bias power supply in the grid system will apply a bias to the K groups of symmetrical grids; wherein the K groups of symmetrical grids correspond to the axial position of the K groups of symmetrical gas supply pipes selected in step 1-2; the bias power supply applies a positive bias to each negative sector-shaped grid in the K groups of symmetrical grids, and applies a negative bias to each positive sector-shaped grid in the K groups of symmetrical grids.

[0090] In this embodiment, for ease of operation, it is preferred that a main switch is provided for the gas supply pipeline valves and the sector grid power supply in the same discharge zone.

[0091] Steps 1-5: Plasma formation

[0092] The central cathode 3 starts to emit primary electrons, which evenly enter the 2N discharge areas.

[0093] The primary electrons entering the K symmetrical discharge regions collide with the working gas supplied by the symmetrical gas supply pipes to generate plasma. The K symmetrical discharge regions correspond to the axial positions of the K symmetrical gas supply pipes selected in steps 1-2, namely, the positive discharge region A and the negative discharge region D.

[0094] The primary electrons in the negative discharge region D and the electronegative working fluid gas supplied by the electronegative working fluid supply pipe C 60 Collisions will occur upstream of the discharge chamber 1, generating an "electron-ion" plasma.

[0095] The magnetic filter device 7 confines the electrons in the plasma upstream of the discharge chamber 1. The plasma contains high-energy electrons and low-energy electrons. The high-energy electrons are used to increase the positive ion density, while the low-energy electrons can combine with neutral particles to increase the negative ion density. As a result, the negative ion density in the downstream area of ​​the discharge chamber 1 is much higher than that of the electrons, thus forming an "ion-ion" plasma. In this embodiment, due to C 60 It is an electronegative working gas. The low-energy electrons in the "electron-ion" plasma react with C 60 Neutral atoms have strong binding properties, so negative ion plasma C is generated downstream of the negative discharge region D. 60 - , that is, C downstream of the negative discharge area D 60 - High density.

[0096] The primary electrons in the positive discharge region A collide with the working fluid gas Xe supplied by the working fluid gas supply pipe upstream of the discharge chamber 1 to generate "electron-ion" plasma.

[0097] Since Xe is a non-strong electronegative working fluid (the electronegativity is less than one of the electronegative working fluid gas), the electrons in the "electron-ion" plasma are weakly bound to the neutral Xe atoms, so the Xe in the downstream of the positive discharge region A is + High density.

[0098] The primary electrons entering the remaining NK group of symmetrical discharge regions (i.e., discharge regions B, C, E, and F) will be collected by the walls of the corresponding discharge regions.

[0099] Steps 1-6: Extracting and accelerating plasma

[0100] The negative sector grid in the K group of symmetrical grids will extract and accelerate the negative ions in the plasma ejected from the tail end of the negative discharge region. In this embodiment, a negative bias is applied to the grid in the positive discharge region A to extract and accelerate Xe + ; Positive bias is applied to the negative discharge region D to extract and accelerate C 60 - .

[0101] The accelerated negative ions will generate a partial thrust F1 for the Kaufman ion thruster; the positive fan-shaped grid in the K group of symmetrical grids will extract and accelerate the positive ions in the plasma ejected from the tail end of the positive discharge region, and the accelerated positive ions will generate a partial thrust F2 for the Kaufman ion thruster.

[0102] Step 1-7, ion beam neutralization: After being accelerated by each set of symmetrical grids, the negative and positive ions are controlled by using the existing proportional integral differential to achieve self-neutralization.

[0103] Step 1-8, orbit control: While the ion beam is being neutralized, the sum of all the partial thrusts F1 and F2 will form the total axial thrust F through the center of mass of the Kaufman ion thruster, which can be used for orbit control.

[0104] At this point, the total thrust F passes through the center of mass, and the sum of the thrust moments in the positive discharge region A and the negative discharge region D is zero. Therefore, only axial thrust is provided, which can be used for orbit control. The operating principles of the remaining centripetal thrust modes are similar and will not be described in detail.

[0105] B. Eccentric thrust mode - attitude adjustment

[0106] The above-mentioned attitude adjustment method of the Kaufman ion thruster preferably includes the following steps.

[0107] Step 2-1, combining eccentric discharge regions: An adjacent positive discharge region and a negative discharge region are referred to as a group of eccentric discharge regions; thus, 2N discharge regions are formed into the first, second, third, ..., and N-1th groups of eccentric discharge regions in a clockwise or counterclockwise direction, respectively; an electronegative working fluid gas supply pipe and a working fluid gas supply pipe corresponding to each group of eccentric discharge regions are referred to as a group of eccentric gas supply pipes; and a positive sector-shaped grid and a negative sector-shaped grid corresponding to each group of eccentric discharge regions are referred to as a group of eccentric grids.

[0108] Step 2-2, select J groups of eccentric gas supply tubes: Based on the current attitude and adjusted attitude of the Kaufman ion thruster, calculate the rotational thrust torque M required for attitude adjustment, and then select the starting number J of eccentric gas supply tubes and the circumferential position of the J groups of eccentric gas supply tubes; where 1≤J≤N-1; the eccentric discharge area corresponding to the axial position of the J group of eccentric gas supply tubes is called the J group of eccentric discharge area; and the eccentric grid corresponding to the axial position of the J group of eccentric gas supply tubes is called the J group of eccentric grid.

[0109] In this embodiment, J=1 is taken as an example for detailed description. The present invention corresponds to N-1 eccentric thrust modes.

[0110] Step 2-3, start gas supply: Synchronously start the J groups of eccentric gas supply pipes selected in step 2-2; each group of eccentric gas supply pipes supplies gas to the corresponding positive discharge area or negative discharge area at a set fixed flow rate; the electronegative working fluid supply pipes in the eccentric gas supply pipes supply electronegative working fluid gas 1 to the corresponding negative discharge area, and the working fluid supply pipes in the eccentric gas supply pipes supply electronegative working fluid gas 2 or non-electronegative working fluid gas to the corresponding positive discharge area. The fixed flow rates of the electronegative working fluid supply pipes and the working fluid supply pipes in each group of eccentric gas supply pipes are different, and all electronegative working fluid supply pipes have the same fixed flow rate.

[0111] In this embodiment, the activation of the eccentric gas supply pipe corresponding to the positive discharge area A and the negative discharge area B is taken as an example for detailed description.

[0112] Step 2-4, start the J group of eccentric grids: while starting the gas supply in step 1-3, the bias power supply in the grid system will apply a bias to the J group of eccentric grids; the bias power supply applies a positive bias to each negative sector-shaped grid in the J group of eccentric grids, and applies a negative bias to each positive sector-shaped grid in the J group of eccentric grids.

[0113] Step 2-5: Plasma formation

[0114] The central cathode 3 starts to emit primary electrons, which evenly enter the 2N discharge areas.

[0115] The primary electrons entering the J group of eccentric discharge regions (i.e., the positive discharge region A and the negative discharge region B) will collide with the working gas supplied by the eccentric gas supply pipe to generate plasma.

[0116] The primary electrons in the negative discharge region B collide with the electronegative working fluid gas supplied from the electronegative working fluid supply pipe to generate "electron-ion" plasma. After passing through the magnetic filter device 7, "ion-ion" plasma containing positive ions and negative ions is generated downstream of the negative discharge region. The specific principle is the same as steps 1-5 and will not be repeated here.

[0117] Primary electrons in the positive discharge region A collide with the electronegative working gas II or the non-electronegative working gas supplied by the working gas supply pipe to generate an "electron-ion" plasma. After passing through the magnetic filter device 7, an "ion-ion" plasma containing positive and negative ions is generated downstream of the positive discharge region. The negative ion density in the "ion-ion" plasma downstream of the negative discharge region is greater than the negative ion density in the "ion-ion" plasma downstream of the positive discharge region.

[0118] The primary electrons entering the eccentric discharge region of the remaining NJ group will be collected by the wall of the corresponding discharge region.

[0119] Steps 2-6: Extracting and accelerating plasma

[0120] The negative sector-shaped grids in the J group of eccentric grids will extract and accelerate the negative ions in the plasma ejected from the tail end of the negative discharge region. The accelerated negative ions will generate a partial thrust F1' for the Kaufman ion thruster; the positive sector-shaped grids in the J group of eccentric grids will extract and accelerate the positive ions in the plasma ejected from the tail end of the positive discharge region. The accelerated positive ions will generate a partial thrust F2' for the Kaufman ion thruster.

[0121] Step 2-7, ion beam neutralization: negative ions and positive ions accelerated by each set of eccentric grids are self-neutralized.

[0122] Step 2-8, attitude adjustment: While the ion beam is being neutralized, the sum of all partial thrusts F1' and F2' will generate a rotational torque M on the center of mass of the Kaufman ion thruster, thereby achieving attitude adjustment of the Kaufman ion thruster.

[0123] At this point, the total thrust does not pass the center of mass, and the total thrust exerts a moment M on the center of mass. The sum of the moments in the positive discharge region A and the negative discharge region B is not zero, providing a rotational torque that can be used for spacecraft attitude control. The other eccentric thrust modes operate in a similar manner.

[0124] The thrust regulation of the present invention does not rely on changes in the flow rate of the air supply pipe, so the thrust regulation is precise and can adapt to aerospace missions such as gravitational wave detection or high-resolution earth observation.

[0125] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the scope of protection of the present invention.

Claims

1. A Kaufman ion thruster with quantitatively controllable thrust and self-neutralization, characterized by: It includes discharge chamber, central cathode, gas supply assembly, steel magnetic assembly, insulating partition and grid system; The tail end of the discharge chamber is open, and the front end is provided with a front panel; the discharge chamber comprises a small cylindrical chamber, a transition frustum chamber and a large cylindrical chamber arranged in sequence along the axial direction; the outer diameter of the small cylindrical chamber is smaller than the outer diameter of the large cylindrical chamber; The center cathode is coaxially inserted in the center of the front panel; The gas supply assembly includes N electronegative working fluid gas supply pipes and N working fluid gas supply pipes; wherein N ≥ 2; N electronegative working fluid gas supply pipes and N working fluid gas supply pipes are evenly and staggeredly arranged on the front panel of the central cathode periphery; The steel magnetic assembly is used to form an annular cusp field in the discharge chamber. The steel magnetic assembly includes cathode end magnets, column segment magnets, and grid end magnets. The cathode end magnets are coaxially arranged in the shell of the small cylindrical chamber on the outer periphery of the central cathode. The column segment magnets are coaxially embedded in the upstream end of the large cylindrical chamber shell, and the grid end magnets are coaxially embedded in the downstream end of the large cylindrical chamber shell and adjacent to the sector-shaped grid. The insulating partition includes a central connecting rod and 2N fins; the central connecting rod is coaxially inserted in the discharge chamber, and the 2N fins are evenly arranged along the circumference of the central connecting rod and divide the discharge chamber into 2N discharge zones; an axial discharge gap is formed between the upstream end of the 2N fins and the tail end of the central cathode; and the tail ends of the 2N fins extend from the tail end of the discharge chamber. The 2N discharge regions correspond one-to-one to the N electronegative working fluid gas supply pipes and the N working fluid gas supply pipes, wherein the discharge region corresponding to the N electronegative working fluid gas supply pipes is called a negative discharge region, and the discharge region corresponding to the N working fluid gas supply pipes is called a positive discharge region; the N electronegative working fluid gas supply pipes are used to supply electronegative working fluid gas 1 to the N negative discharge regions, and the N working fluid gas supply pipes are used to supply electronegative working fluid gas 2 or non-electronegative working fluid gas to the N positive discharge regions; the electronegativity of the electronegative working fluid gas 2 is less than that of the electronegative working fluid gas 1; The gate system includes a bias power supply and 2N sector-shaped gates connected to the bias power supply. The 2N sector-shaped gates are arranged at the tail ends of the 2N discharge areas. Among them, the sector-shaped gates corresponding to the negative discharge area are called negative sector-shaped gates, and the sector-shaped gates corresponding to the positive discharge area are called positive sector-shaped gates. The bias power supply can apply a positive bias to each negative sector-shaped gate and a negative bias to each positive sector-shaped gate.

2. The Kaufman ion thruster with quantitatively controllable and self-neutralizing thrust according to claim 1, characterized in that: The gas supply assembly also includes an electronegative working fluid gas source and a conventional working fluid gas source; The electronegative working gas source is filled with electronegative working gas 1; the conventional working gas source is filled with electronegative working gas 2 or non-electronegative working gas; Each electronegative working fluid gas supply pipe is connected to an electronegative working fluid gas source through valve one; each working fluid gas supply pipe is connected to a conventional working fluid gas source through valve two.

3. The Kaufman ion thruster with quantitatively controllable and self-neutralizing thrust according to claim 1, characterized in that: N=3 or 4.

4. The Kaufman ion thruster with quantitatively controllable and self-neutralizing thrust according to claim 1, characterized in that: The 2N fins are located in the transition cone chamber and the large cylindrical chamber, and the outer end of each fin is sealed to the inner wall of the transition cone chamber and the large cylindrical chamber; the tail end of the central cathode is located in the small cylindrical chamber; The tail ends of the N electronegative working fluid supply pipes all pass through the small cylindrical chamber and then extend into the N negative discharge areas; the tail ends of the N working fluid supply pipes all pass through the small cylindrical chamber and then extend into the N positive discharge areas.

5. The Kaufman ion thruster with quantitatively controllable and self-neutralizing thrust according to claim 1, characterized in that: The utility model also comprises a magnetic filtering device, which is coaxially sleeved on the middle outer periphery of the large cylindrical chamber.

6. The Kaufman ion thruster with quantitatively controllable and self-neutralizing thrust according to claim 1, characterized in that: Each sector grid comprises a sector screen grid and an accelerating sector grid which are arranged in parallel in sequence along the axial direction; an insulating mica sheet is arranged between the outer edge of the sector screen grid and the outer edge of the accelerating sector grid.

7. A method for operating a Kaufman ion thruster with quantitatively controllable and self-neutralizing thrust according to any one of claims 1 to 6, characterized in that: By controlling the gas supply start timing of N electronegative working fluid gas supply pipes and N working fluid gas supply pipes, the orbit control and attitude adjustment of the Kaufman ion thruster can be achieved.

8. The method for operating a Kaufman ion thruster with quantitatively controllable and self-neutralizing thrust according to claim 7, characterized in that: The orbit control method of the Kaufman ion thruster comprises the following steps: Step 1-1, combining symmetrical discharge regions: a positive discharge region and a negative discharge region symmetrical about the axis of the discharge chamber are referred to as a group of symmetrical discharge regions; an electronegative working fluid gas supply pipe and a working fluid gas supply pipe corresponding to each group of symmetrical discharge regions form a group of symmetrical gas supply pipes; a positive sector-shaped grid and a negative sector-shaped grid corresponding to each group of symmetrical discharge regions form a group of symmetrical grids; thus, the discharge chamber has N groups of symmetrical discharge regions, and the gas supply assembly has N groups of symmetrical gas supply pipes; The gate system has N groups of symmetrical gates; Step 1-2: Select the number of starting groups of the symmetrical air supply pipes: Select the number K of starting groups of the symmetrical air supply pipes based on the total thrust F required for orbit control of the Kaufman ion thruster; wherein the number K of starting groups is proportional to the total thrust F, and 1≤K≤N; Step 1-3, start gas supply: Synchronously start the K groups of symmetrical gas supply pipes selected in step 1-2; each group of symmetrical gas supply pipes supplies gas to the corresponding positive discharge area or negative discharge area at the same set fixed flow rate; wherein, the electronegative working fluid gas supply pipe in the symmetrical gas supply pipe will supply electronegative working fluid gas 1 to the corresponding negative discharge area, and the working fluid gas supply pipe in the symmetrical gas supply pipe will supply electronegative working fluid gas 2 or non-electronegative working fluid gas to the corresponding positive discharge area; Step 1-4, starting K groups of symmetrical grids: At the same time as the gas supply is started in step 1-3, the bias power supply in the grid system applies a bias voltage to the K groups of symmetrical grids; wherein the K groups of symmetrical grids correspond to the axial positions of the K groups of symmetrical gas supply pipes selected in step 1-2; the bias power supply applies a positive bias voltage to each negative sector grid in the K groups of symmetrical grids, and applies a negative bias voltage to each positive sector grid in the K groups of symmetrical grids; Step 1-5, plasma formation: The central cathode starts emitting primary electrons, which uniformly enter 2N discharge regions. The primary electrons entering the K symmetrical discharge regions collide with the working fluid gas supplied by the symmetrical gas supply pipes to generate plasma. The primary electrons collide with the electronegative working fluid gas 1 supplied by the electronegative working fluid supply pipe to generate an "electron-ion" plasma, and an "ion-ion" plasma containing positive and negative ions is generated downstream of the negative discharge region. The primary electrons collide with the electronegative working fluid gas 2 or the non-electronegative working fluid gas supplied by the working fluid supply pipe to generate an "electron-ion" plasma, and an "ion-ion" plasma containing positive and negative ions is generated downstream of the positive discharge region. The negative ion density in the "ion-ion" plasma downstream of the negative discharge region is greater than the negative ion density in the "ion-ion" plasma downstream of the positive discharge region. The K symmetrical discharge regions correspond to the axial positions of the K symmetrical gas supply pipes selected in step 1-2. The primary electrons entering the remaining NK symmetrical discharge regions are collected by the walls of the corresponding discharge regions. Steps 1-6, extracting and accelerating plasma: The negative sector-shaped grids in the K-group symmetrical grids will extract and accelerate negative ions in the plasma ejected from the tail end of the negative discharge region. The accelerated negative ions will generate a partial thrust F1 for the Kaufman ion thruster; the positive sector-shaped grids in the K-group symmetrical grids will extract and accelerate positive ions in the plasma ejected from the tail end of the positive discharge region. The accelerated positive ions will generate a partial thrust F2 for the Kaufman ion thruster. Step 1-7, ion beam neutralization: negative ions and positive ions accelerated by each set of symmetrical grids are self-neutralized; Step 1-8, orbit control: While the ion beam is being neutralized, the sum of all the partial thrusts F1 and F2 will form the total axial thrust F through the center of mass of the Kaufman ion thruster, which can be used for orbit control.

9. The method for operating a Kaufman ion thruster with quantitatively controllable and self-neutralizing thrust according to claim 7, characterized in that: The attitude adjustment method of the Kaufman ion thruster comprises the following steps: Step 2-1, combining eccentric discharge regions: An adjacent positive discharge region and a negative discharge region are referred to as a group of eccentric discharge regions; thus, 2N discharge regions are formed into the first, second, third, ..., and N-1th groups of eccentric discharge regions in a clockwise or counterclockwise direction; an electronegative working fluid gas supply pipe and a working fluid gas supply pipe corresponding to each group of eccentric discharge regions are referred to as a group of eccentric gas supply pipes; and a positive sector-shaped grid and a negative sector-shaped grid corresponding to each group of eccentric discharge regions are referred to as a group of eccentric grids; Step 2-2, select J groups of eccentric gas supply tubes: Based on the current attitude and adjusted attitude of the Kaufman ion thruster, calculate the rotational thrust torque M required for attitude adjustment, and then select the starting number J of eccentric gas supply tubes and the circumferential position of the J groups of eccentric gas supply tubes; where 1≤J≤N-1; the eccentric discharge region corresponding to the axial position of the J group of eccentric gas supply tubes is called the J group of eccentric discharge region; the eccentric grid corresponding to the axial position of the J group of eccentric gas supply tubes is called the J group of eccentric grid; Step 2-3, start gas supply: Synchronously start the J groups of eccentric gas supply pipes selected in step 2-2; each group of eccentric gas supply pipes supplies gas to the corresponding positive discharge area or negative discharge area at a set fixed flow rate; wherein, the electronegative working fluid gas supply pipe in the eccentric gas supply pipe will supply electronegative working fluid gas 1 to the corresponding negative discharge area, and the working fluid gas supply pipe in the eccentric gas supply pipe will supply electronegative working fluid gas 2 or non-electronegative working fluid gas to the corresponding positive discharge area; Step 2-4, start the J-group eccentric grids: while starting the gas supply in step 1-3, the bias power supply in the grid system will apply a bias voltage to the J-group eccentric grids; the bias power supply applies a positive bias voltage to each negative sector grid in the J-group eccentric grids, and applies a negative bias voltage to each positive sector grid in the J-group eccentric grids; Step 2-5, plasma formation: The central cathode starts emitting primary electrons, which uniformly enter the 2N discharge regions. The primary electrons entering the J groups of eccentric discharge regions collide with the working fluid gas supplied by the eccentric gas supply pipe to generate plasma. The primary electrons collide with the electronegative working fluid gas 1 supplied by the electronegative working fluid supply pipe to generate "electron-ion" plasma, and an "ion-ion" plasma containing positive and negative ions is generated downstream of the negative discharge region. The primary electrons collide with the electronegative working fluid gas 2 or the non-electronegative working fluid gas supplied by the working fluid supply pipe to generate "electron-ion" plasma, and an "ion-ion" plasma containing positive and negative ions is generated downstream of the positive discharge region. The negative ion density in the "ion-ion" plasma downstream of the negative discharge region is greater than the negative ion density in the "ion-ion" plasma downstream of the positive discharge region. The primary electrons entering the remaining NJ groups of eccentric discharge regions are collected by the walls of the corresponding discharge regions. Step 2-6, extracting and accelerating plasma: The negative sector-shaped grids in the J group of eccentric grids will extract and accelerate negative ions in the plasma ejected from the tail end of the negative discharge region. The accelerated negative ions will generate a partial thrust F1' for the Kaufman ion thruster; the positive sector-shaped grids in the J group of eccentric grids will extract and accelerate positive ions in the plasma ejected from the tail end of the positive discharge region. The accelerated positive ions will generate a partial thrust F2' for the Kaufman ion thruster; Step 2-7, ion beam neutralization: after being accelerated by each set of eccentric grids, the negative and positive ions are self-neutralized; Step 2-8, attitude adjustment: While the ion beam is being neutralized, the sum of all partial thrusts F1' and F2' will generate a rotational thrust torque M on the center of mass of the Kaufman ion thruster, thereby achieving attitude adjustment of the Kaufman ion thruster.

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