Beta radioactive isotope coating and magnetic confinement enhanced air-breathing type electric propulsion ionization method

Abstract

The invention discloses a Beta radioactive isotope coating and magnetic confinement enhanced air-breathing electric propulsion ionization method. The method is characterized by comprising the following steps: selecting a plasma generation assembly without electrode discharge; the ionization is enhanced by adopting Beta radioactive isotope; arranging a magnetic field in the beta ray radiation direction to carry out magnetic field constraint; by dynamically adjusting the magnetic induction intensity and regulating and controlling the plasma state and the ionization rate, the Beta radioactive isotope (such as nickel-63) is creatively adopted, and the device has the advantages that the service life is long, the protection requirement is low, and mechanical compression and heating cannot induce nuclear reaction. And the requirement on the activity of the radioactive source is fundamentally reduced, so that the material cost and the safety risk are greatly reduced, and the practicability and the safety of the electric propulsion system are improved.

Description

Technical Field

[0001] This invention belongs to the field of air-breathing electric propulsion technology for ultra-low orbit space, and particularly relates to a Beta radioisotope coating and a magnetically confined enhanced air-breathing electric propulsion ionization method. Background Technology

[0002] The novel applications of ultra-low Earth orbit (UO) space have spurred the rapid development of air-breathing electric propulsion technology. Air-breathing electric propulsion uses the rarefied air in orbit as its propellant; escaping this orbit requires a large amount of propellant for confinement, thus achieving the goal of maintaining orbit for extended periods. However, air is less ionizable than xenon, a commonly used gas in electric propulsion. Insufficient ionization results in fewer ions available to generate thrust, leading to low electric propulsion efficiency. Therefore, existing electric propulsion technologies urgently need to adopt methods to enhance ionization to make air a suitable propellant.

[0003] The ionization of gas by radioactive isotope radiation particles is a known physical phenomenon. Utilizing the ionization of gas on the surface of spacecraft to control the boundary layer is an international research direction. The China Institute of Atomic Energy has conducted similar work in the past decade or so. For example... Figure 2-5 The figures show the spatial distribution of ionization yields for alpha and beta particles at different energies and activities. It is evident that the ionization yield of alpha particles is 2-3 orders of magnitude higher than that of beta particles, and the ionization rate is approximately proportional to the activity. Therefore, alpha particle radionuclides become a viable option.

[0004] However, this method is not yet fully developed because ionization using alpha particles alone requires higher radioactivity. Higher radioactivity necessitates the use of alpha radioactive sources with extremely high activity. The production of high-activity alpha radionuclides is difficult and extremely expensive, thus making radionuclide production and nuclear protection a bottleneck. Summary of the Invention

[0005] This invention addresses the problems of existing technologies by proposing a Beta radioisotope coating and magnetically confined air-breathing electric propulsion ionization method. The aim is to solve the problems of existing technologies that rely solely on alpha radioparticles for ionization, require higher radioactivity, and face significant challenges in producing high-activity alpha radionuclides due to high difficulty and cost.

[0006] To solve its technical problems, the present invention proposes the following technical solutions: A method for ionization using a beta-radioisotope coating and magnetically confined air-breathing electric propulsion is characterized by the following steps: Step 1: Select a plasma generation component with electrodeless discharge; Step 2: Enhance ionization using Beta radioisotopes; Step 3: Arrange a magnetic field in the direction of beta ray emission to perform magnetic field confinement; Step 4: Regulate the plasma state and ionization rate by dynamically adjusting the magnetic induction intensity.

[0007] Furthermore, the plasma generating components in step one include: ICP, Helicon, and ECR discharge device.

[0008] Furthermore, the Beta radioisotope in step two includes nickel-63 isotope.

[0009] Furthermore, when the Beta radioisotope is nickel-63, within the plasma discharge region of the electric thruster, the incident radioactive electrons interact with those in the air. , When molecules collide, when a single / When a molecule interacts with two electrons, it undergoes simultaneous dissociation and ionization, ultimately dissociating into two N⁺ / O⁺ cations and releasing four electrons, as follows: ; Furthermore, in step three, a magnetic field is arranged in the direction of beta ray emission for magnetic field confinement. Specifically, when the beta ray isotope is nickel-63, the magnetic field confinement radius is as follows: 1) Assume the average energy of the emitted electrons is 17 keV; 2) The magnetic field strength is determined based on the radius of gyration: Larmor's radius of curvature for: ; m is the electron mass: 9.11e-31 kg e represents the electric charge: 1.6e-19C E represents the radioactive energy: 17 keV B represents the magnetic flux density, measured in tons (T).

[0010] Based on this, the relationship between magnetic flux density and Larmor cyclotron radius can be estimated: ; Furthermore, for a discharge chamber with a diameter of 400 mm, the required magnetic induction intensity is 1e-3 T; for a small discharge chamber such as one with a diameter of 10 mm, the required magnetic induction intensity is 0.04 T.

[0011] Furthermore, the fourth step of regulating the plasma state and ionization rate by dynamically adjusting the magnetic induction intensity specifically involves: using an electromagnet to construct a magnetic field, and dynamically adjusting the magnetic induction intensity to regulate the plasma state and ionization rate.

[0012] Furthermore, the method of using electromagnets to construct a magnetic field and dynamically adjusting the magnetic induction intensity to control the plasma state and ionization rate is as follows: when the ionization rate decreases due to factors such as the peeling of the radioactive isotope coating, radioactivity decay, or an increase in the density of the working gas in the discharge chamber, the magnetic induction intensity is increased to confine higher-energy radioactive electrons while maintaining a constant electron larmor cyclotron radius, thereby enhancing the collision frequency and collision energy between the electrons and neutral working molecules, and thus improving the ionization efficiency of the working fluid.

[0013] Furthermore, the method of using electromagnets to construct a magnetic field and dynamically adjusting the magnetic induction intensity to control the plasma state and ionization rate is as follows: when the ionization rate is too high, the magnetic induction intensity is reduced to decrease the energy and flux of confined radioactive electrons, reduce the collision energy and probability of electrons with working fluid molecules, thereby reducing the ionization rate and suppressing the generation of multiple ionized ions, so as to avoid the decline in thrust energy utilization efficiency and specific impulse, and reduce the risk of thrust short circuit. Advantages and effects of the invention

[0014] 1. Significantly Reduced Radioactivity Requirements, Costs, and Safety Risks: Existing technologies rely on high-activity alpha radioactive particles for ionization, which presents challenges such as difficult preparation, high costs, and significant nuclear protection risks. This invention innovatively employs beta radioisotopes (such as nickel-63), which offer advantages such as long lifetime, low protection requirements, and the fact that mechanical compression and heating do not induce nuclear reactions. This fundamentally reduces the requirements for radioactive source activity, thereby significantly decreasing material costs and safety risks, and improving the practicality and safety of electric propulsion systems.

[0015] 2. To address the low propulsion efficiency caused by insufficient ionization in existing technologies, this invention introduces magnetic field confinement technology: by confining radioactive electrons with a magnetic field, their trajectory in the discharge chamber is extended, increasing the probability of collisions with working gas molecules (such as nitrogen and oxygen), thereby improving ionization efficiency. By dynamically adjusting the magnetic induction intensity, the energy range of the confined electrons is precisely controlled to match the optimal ionization energy of the working gas molecules, optimizing the energy transfer process, reducing ineffective collisions, and further improving ionization efficiency.

[0016] 3. This invention employs an electrodeless discharge mode (such as ICP, Helicon, ECR discharge), avoiding direct contact between the electrodes and high-temperature, corrosive plasma, fundamentally eliminating the electrode wear mechanism. This significantly extends the lifespan of the plasma generation components, enabling it to match the design lifespan of the satellite platform.

[0017] 4. This invention utilizes electromagnets to construct a magnetic field. By dynamically adjusting the magnetic induction intensity, precise control over the plasma state and ionization rate is achieved. When the ionization rate decreases due to factors such as peeling of the radioactive source coating, radioactive decay, or increased working gas density, the magnetic induction intensity can be increased to confine higher-energy radioactive electrons while maintaining the electron Larmor cyclotron radius. This enhances the collision frequency and energy between the electrons and neutral working gas molecules, thereby compensating for and improving ionization efficiency. When the ionization rate is too high, the magnetic induction intensity can be reduced to weaken the energy confinement and flux of radioactive electrons, reducing their collision energy and probability with working gas molecules, thereby suppressing the ionization rate and avoiding the generation of multiple ionized ions. This helps maintain the thruster's energy utilization efficiency and specific impulse, and reduces the risk of short circuits caused by excessive ionization. Attached Figure Description

[0018] Figure 1 This is a flowchart of the Beta radioisotope coating and magnetically confined enhanced air-breathing electric propulsion ionization method of the present invention.

[0019] Figure 2 The relationship between electron-ion pair production rate and distance for different energy radioactive sources; Figure 3 Electron-ion pair production rate of different energy β-radioactive sources varies with distance; Figure 4 The relationship between electron-ion pair production rate and distance for radioactive sources with different activities; Figure 5 The relationship between electron-ion pair production rate and distance for radioactive sources with different activities; Detailed Implementation Innovation of this invention

[0020] One of the innovations is the use of a Beta radioactive source instead of an Alpha radioactive source, abandoning the traditional approach that relies on high-activity, high-cost, and highly radioactive alpha nuclides. The use of long-lived, low-protection-requirement Beta radioisotopes such as nickel-63 fundamentally reduces the system's radioactivity requirements, material costs, and safety risks.

[0021] The second innovation is the introduction of magnetic field confinement technology: After radioactive isotopes produce electrons, these electrons have velocity. If not confined, they will quickly escape from the discharge chamber, where the gas pressure is very low, making it impossible for the gas to intercept them. By applying a confinement magnetic field along the radiation path, the ions are confined within the discharge chamber. This method forces the electrons to undergo helical motion within a set radius of rotation.

[0022] The third innovation is the adoption of an electrodeless discharge mode: combining the aforementioned Beta radiation source and magnetic field technology with a mature electrodeless plasma generator. This type of device directly excites and maintains plasma within a vacuum chamber using an alternating electromagnetic field, completely avoiding direct contact between the electrodes and the high-temperature, corrosive plasma. This fundamentally eliminates electrode sputtering, ablation, and other wear mechanisms, resulting in an extremely long lifespan for the entire plasma generation component, matching the lifespan of the satellite platform.

[0023] Fourth innovation: Dynamic adjustment of magnetic induction intensity: By monitoring parameters such as plasma density and working fluid flow rate in real time, the system can dynamically adjust the current of the electromagnet, thereby changing the magnetic induction intensity. Design principle of the invention

[0024] 1. Design principle of selecting Beta radioisotopes to enhance ionization: Compared to the traditionally envisioned high-activity, high-protection-requirement Alpha radioactive sources, this invention prefers Beta radioactive sources (such as nickel-63). Beta radioisotopes, represented by nickel-63, have a long lifetime (half-life greater than 50 years) and can operate continuously in orbit without energy supply. ② These radioisotopes are relatively safe; mechanical compression and heating will not cause nuclear or chemical reactions. They have been used in the development of nuclear batteries (such as nickel-63 nuclear batteries) and have broad potential applications in industry and medicine (having been implanted in the human body as batteries for pacemakers). ③ Furthermore, their radioactive particles are low-energy electrons, which are easy to protect while being sufficient to ionize the air (e.g., nickel-63 has an average energy of 17 keV and a maximum radiation energy of 66 keV, which can be blocked by a sheet of printing paper). Their kinetic energy can directly ionize working gas molecules (such as...) through collisions, generating initial electrons and ions. ④ Cascade ionization: As described in claim 4, when a single high-energy Beta electron collides with a gas molecule (e.g.), it not only ionizes the molecule but also triggers its dissociation, generating more reactive atoms or groups. These products are more easily ionized by subsequent electrons. This "one-touch-many" chain reaction significantly amplifies the ionization effect of a single radioactive source particle, greatly increasing the overall ionization rate.

[0025] 2. Design Principles of Magnetic Field Confinement: While Beta particles are desirable, their random motion means many particles may be lost on the container walls without sufficient collisions. Magnetic field confinement addresses this issue. ① Extending the Path and Increasing Collisions: By applying a magnetic field along the radial direction, high-speed Beta electrons undergo helical rotation under the Lorentz force. This "confines" the electron's trajectory to the central region of the discharge chamber, increasing the path length by orders of magnitude and significantly increasing the probability of collisions with gas molecules. ② Energy Optimization and Controllability: The strength (magnetic induction intensity B) of the magnetic field generated by the electromagnet can be adjusted precisely and in real time. ③ Controlling Collision Energy: According to the Larmor radius formula (r = mv / qB), the magnetic induction intensity B determines the electron's cyclotron radius. By adjusting B, the energy range of the confined electrons can be controlled, making its energy distribution more compatible with the optimal ionization energy of the working gas molecules, thereby optimizing energy transfer efficiency and reducing ineffective collisions.

[0026] Based on the above principles, this invention designs a Beta radioisotope coating and magnetically confined enhanced air-breathing electric propulsion ionization method, such as... Figure 1 As shown, its characteristics include the following steps: Step 1: Select a plasma generation component with electrodeless discharge; Step 2: Enhance ionization using Beta radioisotopes; Step 3: Arrange a magnetic field in the direction of beta ray emission to perform magnetic field confinement; Step 4: Regulate the plasma state and ionization rate by dynamically adjusting the magnetic induction intensity.

[0027] Furthermore, the plasma generating components in step one include: ICP, Helicon, and ECR discharge device.

[0028] Furthermore, the Beta radioisotope in step two includes nickel-63 isotope.

[0029] Furthermore, when the Beta radioisotope is nickel-63, within the plasma discharge region of the electric thruster, the incident radioactive electrons interact with those in the air. , When molecules collide, when a single / When a molecule interacts with two electrons, it undergoes simultaneous dissociation and ionization, ultimately dissociating into two N⁺ / O⁺ cations and releasing four electrons, as follows: ; Furthermore, in step three, a magnetic field is arranged in the direction of beta ray emission for magnetic field confinement. Specifically, when the beta ray isotope is nickel-63, the magnetic field confinement radius is as follows: 1) Assume the average energy of the emitted electrons is 17 keV; 2) The magnetic field strength is determined based on the radius of gyration: Larmor's radius of curvature for: ; m is the electron mass: 9.11e-31 kg e represents the electric charge: 1.6e-19C E represents the radioactive energy: 17 keV B represents the magnetic flux density, measured in tons (T).

[0030] Based on this, the relationship between magnetic flux density and Larmor cyclotron radius can be estimated: ; Furthermore, for a discharge chamber with a diameter of 400 mm, the required magnetic induction intensity is 1e-3 T; for a small discharge chamber such as one with a diameter of 10 mm, the required magnetic induction intensity is 0.04 T.

[0031] Furthermore, the fourth step of regulating the plasma state and ionization rate by dynamically adjusting the magnetic induction intensity specifically involves: using an electromagnet to construct a magnetic field, and dynamically adjusting the magnetic induction intensity to regulate the plasma state and ionization rate.

[0032] Furthermore, the method of using electromagnets to construct a magnetic field and dynamically adjusting the magnetic induction intensity to control the plasma state and ionization rate is as follows: when the ionization rate decreases due to factors such as the peeling of the radioactive isotope coating, radioactivity decay, or an increase in the density of the working gas in the discharge chamber, the magnetic induction intensity is increased to confine higher-energy radioactive electrons while maintaining a constant electron larmor cyclotron radius, thereby enhancing the collision frequency and collision energy between the electrons and neutral working molecules, and thus improving the ionization efficiency of the working fluid.

[0033] Furthermore, the method of using electromagnets to construct a magnetic field and dynamically adjusting the magnetic induction intensity to control the plasma state and ionization rate is as follows: when the ionization rate is too high, the magnetic induction intensity is reduced to decrease the energy and flux of confined radioactive electrons, reduce the collision energy and probability of electrons with working fluid molecules, thereby reducing the ionization rate and suppressing the generation of multiple ionized ions, so as to avoid the decline in thrust energy utilization efficiency and specific impulse, and reduce the risk of thrust short circuit.

[0034] It should be emphasized that the above specific embodiments are merely explanations of the present invention and are not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to the above embodiments without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A method of ionization for a beta radioisotope coated, magnetically confined, enhanced- getter, electric propulsion, characterized by: The method comprises the following steps: Step one, selecting a plasma generating assembly without electrode discharge; Step two, using a beta radiation isotope to enhance ionization; Step three, arranging a magnetic field in the direction of beta radiation for magnetic field confinement; Step four, regulating the plasma state and ionization rate by dynamically adjusting the magnetic induction intensity.

2. A method of ionization for a magnetic confinement enhanced sorbiton electric propulsion with a coating of a beta radioisotope according to claim 1, characterized in that: The plasma generating assembly of step one comprises ICP, Helicon, and ECR discharge device.

3. A method of ionization of a Beta radioisotope coating with magnetic confinement enhanced sorbiton electric propulsion according to claim 1, characterized in that: The beta radiation isotope of step two comprises nickel 63 isotope.

4. A method of ionization for a magnetic confinement, enhanced-getter, electric propulsion of a Beta radioisotope coating according to claim 3, characterized in that: When the beta radioisotope is nickel 63, in the plasma discharge region of an electric thruster, the incident radiolytic electrons interact with air molecules , When a single molecule collides with 2 electrons, the dissociation and ionization processes occur simultaneously, and the molecule is finally dissociated and ionized into 2 N⁺ / O⁺ positive ions, accompanied by the release of 4 electrons, as follows: / When a single molecule collides with 2 electrons, the dissociation and ionization processes occur simultaneously, and the molecule is finally dissociated and ionized into 2 N⁺ / O⁺ positive ions, accompanied by the release of 4 electrons, as follows: 。 5. A method of ionization for a magnetic confinement enhanced sorbiton electric propulsion with a coating of a Beta radioisotope according to claim 1, characterized in that: The magnetic field confinement in the direction of beta radiation of step three is specifically as follows: when the beta radiation isotope is nickel 63, the magnetic field confinement radius is as follows: 1) assuming that the average energy of the radiation electrons is 17 keV; 2) the magnetic induction intensity is determined based on the gyroradius: Larmor gyroradius is: ； m is the electron mass: 9.11e-31 kg e is the charge amount: 1.6e-19 C E is the radiation energy: 17 keV B is the magnetic induction intensity, and the unit is T; Accordingly, the relationship between the magnetic induction intensity and the Larmor gyroradius can be estimated: 。 6. A method of ionization for a magnetic confinement, enhanced-getter, electric propulsion of a Beta radioisotope coating according to claim 5, characterized in that: For a discharge chamber with a diameter of 400 mm, the required magnetic induction intensity is 1e-3 T; for a small discharge chamber with a diameter of 10 mm, the required magnetic induction intensity is 0.04 T.

7. A method of ionization for a magnetic confinement, enhanced-getter, electric propulsion of a Beta radioisotope coating according to claim 1, characterized by: The regulation of the plasma state and ionization rate by dynamically adjusting the magnetic induction intensity of step four is specifically as follows: a magnetic field is constructed by using an electromagnet, and the plasma state and ionization rate are regulated by dynamically adjusting the magnetic induction intensity.

8. A method of ionization for a magnetic confinement, enhanced-getter, electric propulsion of a Beta radioisotope coating according to claim 7, characterized in that: The regulation of the plasma state and ionization rate by dynamically adjusting the magnetic induction intensity of step four is specifically as follows: when the radioisotope coating peels off, the radioactivity decays, or the density of the discharge chamber working gas increases, and other factors cause the ionization rate to decrease, the magnetic induction intensity is increased to constrain the radiation electrons with higher energy, enhance the collision frequency and collision energy of the radiation electrons and the neutral working gas molecules, and thus improve the ionization efficiency of the working gas.

9. A method of ionization for a magnetic confinement, enhanced-getter, electric propulsion of a Beta radioisotope coating according to claim 7, characterized in that: The regulation of the plasma state and ionization rate by dynamically adjusting the magnetic induction intensity of step four is specifically as follows: when the ionization rate is too high, the magnetic induction intensity is reduced to reduce the energy and flux of the constrained radiation electrons, reduce the collision energy and collision probability of the electrons and the working gas molecules, thus reduce the ionization rate and inhibit the generation of multiple ionization ions, so as to avoid the decay of the energy utilization efficiency and specific impulse of the thruster, and reduce the short circuit risk of the thruster.

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