A novel micro cathode arc thruster and its acceleration method

Abstract

The present invention discloses a novel micro-cathode arc thruster and an acceleration method thereof, relating to the field of CubeSat propulsion. The micro-cathode arc thruster comprises a thruster, a trumpet-shaped accelerating electrode, and a power processing unit. The high-potential output end of the power processing unit is respectively connected to the anode of the thruster and the trumpet-shaped accelerating electrode, and the cathode of the thruster is connected to the low-potential output end of the power processing unit. The power processing unit is used to generate a transient high voltage between the anode and cathode of the thruster, forming a plasma flow ejected from the nozzle of the thruster. The trumpet-shaped accelerating electrode is arranged at the nozzle of the thruster and is used to accelerate the plasma flow. The present invention achieves acceleration of ions in the plasma flow ejected by the thruster without adding an additional power device.

Description

Technical Field

[0001] The present invention relates to the field of CubeSat propulsion, and in particular to a novel micro cathode arc thruster and an acceleration method thereof. Background Art

[0002] Microcathode arc thrusters have the characteristics of high specific impulse, low power, small size and low mass, making them suitable as CubeSat propulsion devices and have great development prospects. Existing methods for improving the performance of microcathode arc thrusters mainly include: installing an acceleration grid and a magneto-plasma dynamic thruster (MPDT) device at the nozzle of the microcathode arc thruster. The propulsion performance of microcathode arc thrusters is improved by accelerating ions. Although ion acceleration can improve the propulsion performance of the thruster, the acceleration device often introduces a new energy supply device, resulting in energy loss. Summary of the Invention

[0003] The purpose of the present invention is to provide a novel micro cathode arc thruster and an acceleration method thereof, so as to accelerate ions in a plasma flow ejected by the thruster.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] In a first aspect, the present invention provides a novel micro cathode arc thruster, comprising a thruster, a trumpet-shaped accelerating electrode, and a power processing unit;

[0006] The high-potential output end of the power processing unit is connected to the anode of the thruster and the trumpet-shaped accelerating electrode respectively, and the cathode of the thruster is connected to the low-potential output end of the power processing unit;

[0007] The power processing unit is used to generate a transient high voltage between the anode and cathode of the thruster, forming a plasma flow ejected from the nozzle of the thruster;

[0008] The horn-shaped accelerating electrode is arranged at the nozzle of the thruster, and the horn-shaped accelerating electrode is used to accelerate the plasma flow.

[0009] Furthermore, the thruster includes a cathode, an insulating structure, an anode and a magnet arranged in sequence from the inside to the outside; the cathode is cylindrical; the insulating structure, the magnet and the anode of the thruster are all annular structures.

[0010] Furthermore, the power processing unit includes a power supply, a resistor, an insulated gate bipolar transistor and a capacitor; the emitter of the insulated gate bipolar transistor is the high potential output terminal of the power processing unit, and the cathode of the power supply is the low potential output terminal of the power processing unit;

[0011] The emitter of the insulated gate bipolar transistor is connected to the anode of the thruster, and the collector of the insulated gate bipolar transistor is connected to one end of the resistor and one end of the capacitor respectively;

[0012] A pulse signal is input to the gate of the insulated gate bipolar transistor to control the insulated gate bipolar transistor to be turned on and off;

[0013] The other end of the resistor is connected to the positive electrode of the power supply;

[0014] The cathode of the thruster and the other end of the capacitor are both connected to the negative electrode of the power supply.

[0015] Furthermore, the horn expansion angle of the horn-shaped accelerating electrode varies within a range of (π / 2, π).

[0016] In a second aspect, the present invention provides a novel micro-cathode arc thruster acceleration method, which is applied to any of the novel micro-cathode arc thrusters described above, and the acceleration method comprises:

[0017] When the insulated gate bipolar transistor in the power processing unit is turned on, a transient high-voltage plasma flow is formed between the anode and cathode of the thruster, and the trumpet-shaped accelerating electrode forms a transient electric field at the nozzle of the thruster;

[0018] The electrons in the plasma flow are bounded by the magnets of the thruster to form a guiding magnetic field;

[0019] Under the action of the guiding magnetic field, the plasma flow moves away from the nozzle and enters the transient electric field. The transient electric field accelerates the plasma flow in the axial direction of the thruster and decelerates the plasma flow in the radial direction of the thruster.

[0020] Furthermore, the instantaneous electric field causes the plasma flow to accelerate in the axial direction of the thruster and decelerate in the radial direction of the thruster, specifically:

[0021] In the instantaneous electric field, the plasma flow is constrained by the radial electric field component formed by the instantaneous electric field in the radial direction of the thruster, so that the plasma flow is decelerated in the radial direction of the thruster; the plasma flow is acted upon by the axial electric field component formed by the instantaneous electric field in the axial direction of the thruster, so that the ions are accelerated in the axial direction of the thruster; wherein, the expression of the radial electric field component is: The expression of the axial electric field component is:

[0022] in, is the potential generated by the coupling between the infinitesimal element at any point in the horn-shaped accelerating electrode and the cathode of the thruster, α is the infinitesimal angle of the horn-shaped accelerating electrode, which is the angle formed by the straight line between any point in the horn-shaped accelerating electrode and the endpoint of the cathode at one end of the nozzle and the straight line where the cathode is located, and L is the horizontal distance from any point in the horn-shaped accelerating electrode to the endpoint of the cathode at one end of the nozzle.

[0023] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0024] The novel micro-cathode arc thruster of the present invention includes a thruster, a trumpet-shaped accelerating electrode and a power processing unit. The trumpet-shaped accelerating electrode is connected to the high-potential output end of the power processing unit. When the power processing unit provides transient high voltage to the anode and cathode of the thruster, the trumpet-shaped accelerating electrode obtains transient high voltage to form an accelerating electric field, which reduces the radial velocity of the plasma flow and increases the axial velocity of the plasma flow, thereby achieving the purpose of confining the plasma flow and increasing the velocity of the plasma flow. This enhances the thrust of the thruster and reduces energy consumption without the need for an additional power device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 A circuit schematic diagram of a novel micro cathode arc thruster provided in Example 1 of the present invention;

[0027] Figure 2 Schematic diagram of the relationship between the trumpet-shaped accelerating electrode and the anode and cathode of the thruster;

[0028] Figure 3 It is the structural diagram of the trumpet-shaped accelerating electrode;

[0029] Figure 4 Schematic diagram of the thrust distribution of the micro cathode arc thruster. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] The purpose of the present invention is to provide a novel micro cathode arc thruster and an acceleration method thereof, aiming to accelerate the plasma flow ejected by the thruster without adding an additional power device.

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] like Figure 1 As shown, the novel micro cathode arc thruster in this embodiment includes a thruster 1 , a trumpet-shaped accelerating electrode 2 and a power processing unit 3 .

[0035] The high-potential output end of the power processing unit 3 is connected to the anode 11 of the thruster 1 and the trumpet-shaped accelerating electrode 2 respectively, and the cathode 12 of the thruster 1 is connected to the low-potential output end of the power processing unit 3 .

[0036] The power processing unit 3 is used to generate a transient high voltage between the anode 11 and the cathode 12 of the thruster 1 , forming a plasma flow ejected from the nozzle of the thruster 1 .

[0037] The horn-shaped accelerating electrode 2 is arranged at the nozzle of the thruster, and the horn-shaped accelerating electrode 2 is used to accelerate the plasma flow.

[0038] Specifically, the inner diameter of the narrow mouth of the trumpet-shaped accelerating electrode 2 matches the outer diameter of the anode 11 of the thruster 1, and is arranged at the nozzle of the thruster 1. When transient high voltage is provided to the trumpet-shaped accelerating electrode 2, the trumpet-shaped accelerating electrode 2 can form a transient electric field at the nozzle to accelerate the plasma flow ejected from the thruster 1.

[0039] Furthermore, the thruster 1 includes a cathode 12, an insulating structure (not shown) arranged in sequence from the inside to the outside. Figure 1 (pictured), anode 11 and magnet 13; cathode 12 is cylindrical; the insulating structure, magnet 13, and anode 11 of thruster 1 are all annular structures. Specifically, the insulating structure, magnet 13, and anode 11 of thruster 1 are dimensionally matched. The outer diameter of cathode 12 matches the inner diameter of insulating structure, which in turn matches the inner diameter of anode 11, and the outer diameter of anode 11 matches the inner diameter of magnet 13. These components nest within each other through dimensional coordination.

[0040] Furthermore, the power processing unit 3 includes a power supply 32, a resistor 31, an insulated gate bipolar transistor 34 and a capacitor 33; the emitter of the insulated gate bipolar transistor 34 is the high potential output end of the power processing unit 3, and the cathode of the power supply 32 is the low potential output end of the power processing unit 3.

[0041] The emitter of the insulated gate bipolar transistor 34 is connected to the anode 11 of the thruster 1 , and the collector of the insulated gate bipolar transistor 34 is connected to one end of the resistor 31 and one end of the capacitor 33 , respectively.

[0042] The gate of the insulated gate bipolar transistor 34 is connected to a pulse signal to control the switching on and off of the insulated gate bipolar transistor 34 ; the other end of the resistor 31 is connected to the positive electrode of the power supply 32 ; the cathode 12 of the thruster 1 and the other end of the capacitor 33 are both connected to the negative electrode of the power supply 32 .

[0043] The working principle of this embodiment is as follows:

[0044] The gate of IGBT 34 receives a pulse signal, which controls the on and off switching of IGBT 34. When IGBT 34 is off, power supply 31 supplies power to capacitor 33, charging it. When IGBT 34 is on, capacitor 33 discharges, causing thruster 1 to eject a plasma stream. The horn-shaped accelerating electrode 2 experiences a transient high voltage, forming a transient electric field that accelerates the plasma stream. Under the influence of the electric field force of horn-shaped accelerating electrode 2, the radial velocity of the plasma stream decreases, the plasma's focus increases, and the plasma stream acts as a beam, thereby increasing its axial velocity. The transient discharge of capacitor 33 provides a high potential for horn-shaped accelerating electrode 2, achieving plasma acceleration and increasing thrust of the thruster without adding an additional power unit.

[0045] Example 2

[0046] The present invention provides a novel micro-cathode arc thruster acceleration method, which is applied to the novel micro-cathode arc thruster in Example 1. The acceleration method comprises the following steps:

[0047] S101 , when the insulated gate bipolar transistor 34 in the power processing unit 3 is turned on, a transient high-pressure plasma flow is formed between the anode 11 and the cathode 12 of the thruster 1 , and the trumpet-shaped accelerating electrode 2 forms a transient electric field at the nozzle of the thruster 1 .

[0048] S102 : The electrons in the plasma flow are bound by the magnet 13 of the thruster 1 to form a guiding magnetic field.

[0049] S103 , the plasma flow moves away from the nozzle under the action of the guiding magnetic field and enters the transient electric field, and the transient electric field accelerates the plasma flow in the axial direction of the thruster 1 and decelerates in the radial direction of the thruster 1 .

[0050] In the instantaneous electric field, the plasma flow is constrained in the radial direction of the thruster 1 by the radial electric field component formed by the instantaneous electric field, which decelerates the plasma flow in the radial direction of the thruster 1 and acts as a beam on the plasma flow. The plasma flow is acted upon in the axial direction of the thruster 1 by the axial electric field component formed by the instantaneous electric field, which accelerates the plasma flow in the axial direction of the thruster 1.

[0051] See also Figure 2 , point A is any point on the straight line of the horn angle of the horn-shaped accelerating electrode 2 along point B, point B is any point on the horn-shaped accelerating electrode 2, and the angle between the straight line AB and the straight line where the anode 11 of the thruster 1 is located is the horn expansion angle θ, for example Figure 3 The angle γ in the figure is the horn angle. If the horn angle is 150°, the horn expansion angle θ is 60°. Point C is the endpoint of the cathode 12 at one end of the nozzle. The line connecting point B to point C is the direction of the potential drop generated by the coupling between the infinitesimal element of the horn-shaped accelerating electrode 1 at point B and the cathode 12. R1 is the vertical distance from point B to the straight line where the cathode 12 is located. R2 is the vertical distance from point A to the straight line where the cathode 12 is located. L is the horizontal distance from point B to the endpoint C of the cathode 12 at one end of the nozzle. α is the infinitesimal angle of the horn-shaped accelerating electrode. The infinitesimal angle of the horn-shaped accelerating electrode is the angle formed by the straight line where any point in the horn-shaped accelerating electrode 1 and the endpoint of the cathode 12 at one end of the nozzle are located and the straight line where the cathode 12 is located. For example, the angle formed by the straight line where BC is located and the straight line where the cathode 12 is located. The total electric field generated by the potential drop generated by the coupling between the infinitesimal element of point B and the cathode 12 on the line where point BC is located can be estimated as follows:

[0052] like Figure 2 As shown, R1, R2 and L satisfy the relationship: R1=R2+L·tanθ(2)

[0053] The component of the total electric field in the radial direction of the thruster 1 is the radial electric field component E r , whose expression is:

[0054]

[0055] The component of the total electric field generated in the axial direction of the thruster 1 is the axial electric field component E z , whose expression is:

[0056]

[0057] From formulas (2)-(4), it can be concluded that the calculation formula for the microelement angle of the trumpet-shaped accelerating electrode is:

[0058] α=arctan(R2 / L+tanθ)(5)

[0059] According to formula (5), it can be concluded that the horn-shaped accelerating electrode microelement angle and the horn expansion angle have the same change trend, that is, θ and α increase or decrease at the same time. The electric field characteristics of the plume region can be controlled by adjusting α by changing the horn expansion angle θ.

[0060] From formulas (1)-(5), we can deduce the radial electric field component E r and the axial electric field component E z The expressions are:

[0061]

[0062] in, is the potential generated by the coupling between the infinitesimal element at any point in the horn-shaped accelerating electrode and the cathode of the thruster, α is the infinitesimal angle of the horn-shaped accelerating electrode, which is the angle formed by the straight line between any point in the horn-shaped accelerating electrode and the endpoint of the cathode at one end of the nozzle and the straight line where the cathode is located, and L is the horizontal distance from any point in the horn-shaped accelerating electrode to the endpoint of the cathode at one end of the nozzle.

[0063] Furthermore, the range of the horn expansion angle θ is (0, π / 2)

[0064] Specifically, the horn-shaped accelerating electrode accelerates ions in the plasma flow only when its shape is between cylindrical and flat. When the horn-shaped accelerating electrode is cylindrical, its inner diameter is R2 and its length is L. In this case, the horn expansion angle is 0. When the horn-shaped accelerating electrode is flat, the horn expansion angle is π / 2. Therefore, the range of the horn expansion angle is (0, π / 2).

[0065] Obviously, within the range of the horn expansion angle, the radial electric field first increases and then decreases, while the axial electric field first decreases and then increases. Since the radial electric field points to the center line of the channel, it improves the focusing degree of the plasma flow; while the axial electric field is opposite to the acceleration direction of the positive ions in the plasma flow, it hinders the acceleration of positive ions within the range of L. Therefore, there must be an optimal angle that can achieve a strong plasma flow focusing effect and ensure that the obstruction to the acceleration of positive ions is minimized. According to the experimental results, Figure 4 As shown, the speaker angle corresponding to the optimal angle is around 165°.

[0066] It should be noted that the object information (including but not limited to object device information, object personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in the present invention are all information and data authorized by the object or fully authorized by all parties.

[0067] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided by the present invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided by the present invention may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processor involved in each embodiment provided by the present invention may be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, etc., but are not limited to these.

[0068] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A novel micro cathode arc thruster, characterized in that: Includes thrusters, horn-shaped accelerating electrodes and power processing units; The high-potential output end of the power processing unit is connected to the anode of the thruster and the trumpet-shaped accelerating electrode respectively, and the cathode of the thruster is connected to the low-potential output end of the power processing unit; The power processing unit is used to generate a transient high voltage between the anode and cathode of the thruster, forming a plasma flow ejected from the nozzle of the thruster; The horn-shaped accelerating electrode is arranged at the nozzle of the thruster, and the horn-shaped accelerating electrode is used to accelerate the plasma flow.

2. The novel micro cathode arc thruster according to claim 1 is characterized in that: The thruster is provided with a cathode, an insulating structure, an anode and a magnet in sequence from the inside to the outside; the cathode is cylindrical; the insulating structure, the magnet and the anode of the thruster are all annular structures.

3. The novel micro cathode arc thruster according to claim 1 is characterized in that: The power processing unit includes a power supply, a resistor, an insulated gate bipolar transistor and a capacitor; the emitter of the insulated gate bipolar transistor is the high potential output terminal of the power processing unit, and the cathode of the power supply is the low potential output terminal of the power processing unit; The emitter of the insulated gate bipolar transistor is connected to the anode of the thruster, and the collector of the insulated gate bipolar transistor is connected to one end of the resistor and one end of the capacitor respectively; A pulse signal is input to the gate of the insulated gate bipolar transistor to control the insulated gate bipolar transistor to be turned on and off; The other end of the resistor is connected to the positive electrode of the power supply; The cathode of the thruster and the other end of the capacitor are both connected to the negative electrode of the power supply.

4. The novel micro cathode arc thruster according to claim 1 is characterized in that: The horn expansion angle of the horn-shaped accelerating electrode varies in a range of (π / 2, π).

5. A novel acceleration method for a micro cathode arc thruster, characterized in that: Applied to the novel micro cathode arc thruster according to any one of claims 1 to 4, the acceleration method comprises: When the insulated gate bipolar transistor in the power processing unit is turned on, a transient high-voltage plasma flow is formed between the anode and cathode of the thruster, and the trumpet-shaped accelerating electrode forms a transient electric field at the nozzle of the thruster; The electrons in the plasma flow are bounded by the magnets of the thruster to form a guiding magnetic field; Under the action of the guiding magnetic field, the plasma flow moves away from the nozzle and enters the transient electric field. The transient electric field accelerates the plasma flow in the axial direction of the thruster and decelerates the plasma flow in the radial direction of the thruster.

6. The novel micro cathode arc thruster acceleration method according to claim 5, characterized in that: The instantaneous electric field causes the plasma flow to accelerate in the axial direction of the thruster and decelerate in the radial direction of the thruster, specifically: In the instantaneous electric field, the plasma flow is constrained by the radial electric field component formed by the instantaneous electric field in the radial direction of the thruster, so that the plasma flow is decelerated in the radial direction of the thruster; the plasma flow is acted upon by the axial electric field component formed by the instantaneous electric field in the axial direction of the thruster, so that the ions are accelerated in the axial direction of the thruster; wherein, the expression of the radial electric field component is: The expression of the axial electric field component is: in, is the potential generated by the coupling between the infinitesimal element at any point in the horn-shaped accelerating electrode and the cathode of the thruster, α is the infinitesimal angle of the horn-shaped accelerating electrode, which is the angle formed by the straight line between any point in the horn-shaped accelerating electrode and the endpoint of the cathode at one end of the nozzle and the straight line where the cathode is located, and L is the horizontal distance from any point in the horn-shaped accelerating electrode to the endpoint of the cathode at one end of the nozzle.

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