Hall thruster debris motion-plasma dynamics coupled simulation method

Abstract

The application provides a Hall thruster spallation motion-plasma dynamics coupling simulation method, and relates to the technical field of thrusters, and comprises the following steps: sequentially determining charge distribution, potential distribution and electric field distribution to obtain electromagnetic force suffered by particles; determining three-dimensional position coordinates and three-dimensional velocity vectors corresponding to the particles; determining a target particle set reaching a geometric boundary in a three-dimensional space grid and physical processes occurring in the target particle set; determining a resultant force suffered by the spallation and a charge change amount; judging whether the spallation is broken based on a spallation breaking criterion, and determining a charge amount allocated to new spallation generated in a breaking process in the case of breaking; updating a position of a spallation boundary in a three-dimensional space grid according to the resultant force suffered by the spallation; performing collision processing between the particles, and repeating the process until the three-dimensional simulation process is completed. The simulation precision is significantly improved, and the reliability and practicality of the simulation are effectively enhanced.

Description

Technical Field

[0001] This invention relates to the field of thruster technology, and in particular to a coupled simulation method for the motion of debris from a Hall thruster and plasma dynamics. Background Technology

[0002] In the practical operation of the Hall thruster in orbit, discharge disturbances induced by spalling occur frequently, which is a key problem that urgently needs to be solved. However, there is still no simulation study to reveal the coupling process between spalling motion and discharge disturbance. The simulation code implemented by other scholars is usually simulated using a two-dimensional axisymmetric model or a static spalling model because the boundary conditions of moving spalling are difficult to realize. The existing simulation has the following objective shortcomings: (1) In the actual disturbance process, the spalling moves in the plasma field. The effect of the spalling on the discharge disturbance is different at different positions in the plasma field. Although the static assumption can reflect the mechanism of discharge disturbance evolution to a certain extent, it is far from the actual physical process, and the simulation is seriously distorted. (2) The trajectory law of spalling motion has not been determined. The existing simulation has not studied the influence of plasma collision and electromagnetic field on the trajectory of spalling motion, and has not studied the influence of electric force, atomic density gradient force, ion collision force and magnetic force on the trajectory of spalling. (3) The existing simulation has not studied the charge and matter exchange between spalling and plasma field. Since there is a contact surface between the spalled material and the plasma field, and the spalled material is moving, the spalled material will inevitably collide with charged particles in the plasma. After the collision, electrons and ions will form charge deposition on the surface of the spalled material, changing the net charge of the spalled material. This net charge will affect the potential distribution in the plasma, thus affecting the discharge disturbance. The change in net charge will also affect the trajectory of the spalled material. (4) The existing simulation uses a two-dimensional axisymmetric model. In the two-dimensional axisymmetric model, the spalled material is a ring-shaped object, which is very different from the sheet-like spalled material in the real world. The volume of the spalled material in the two-dimensional axisymmetric model is overestimated, and the overestimation of the volume has an impact on the accuracy of the discharge disturbance simulation that is difficult to assess. Therefore, the three-dimensional simulation can be closer to the real physical process and obtain higher simulation credibility. (5) The existing simulation does not realize the simulation of the spalled material breaking process, and does not simulate the disturbance evolution under multiple spalled material disturbances.

[0003] In summary, the simulation results obtained by existing technologies differ from the actual situation, affecting the credibility and practicality of the simulations. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a coupled simulation method for the motion of Hall thruster debris and plasma dynamics, which significantly improves the simulation accuracy and thus effectively enhances the reliability and practicality of the simulation.

[0005] In a first aspect, the present invention provides a coupled simulation method for the motion of Hall thruster debris and plasma dynamics, comprising:

[0006] Step 1: Obtain the three-dimensional spatial mesh corresponding to the Hall thruster. The three-dimensional spatial mesh is generated by meshing based on the geometry of the Hall thruster.

[0007] Step 2: Determine the charge distribution corresponding to the three-dimensional spatial grid within the current time step based on the density of particles contained in the plasma in the Hall thruster and the amount of charge carried by the exfoliated material; wherein, the exfoliated material is modeled as a three-dimensional thin sheet.

[0008] Step 3: Based on the charge distribution, solve for the electric field distribution corresponding to the three-dimensional spatial grid within the current time step;

[0009] Step 4: Based on the three-dimensional position coordinates of the particles contained in the plasma in the Hall thruster at the previous time step, interpolate the electric field distribution to obtain the electromagnetic force on the particles.

[0010] Step 5: Determine the three-dimensional position coordinates and three-dimensional velocity vector of the particle in the current time step based on the electromagnetic force acting on it.

[0011] Step 6: Based on the three-dimensional position coordinates and three-dimensional velocity vector of the particles in the current time step, determine the set of target particles that reach the geometric boundary in the three-dimensional spatial grid and the physical process that occurs therein; wherein, the geometric boundary includes at least the exfoliation boundary in the current time step.

[0012] Step 7: Based on the physical processes that occur in the target particle set relative to the boundary of the debris, determine the resultant force and charge change of the debris in the Hall thruster.

[0013] Step 8: Determine whether the spalling material has broken based on the spalling material breakage judgment criteria, and if it has broken, determine the amount of charge assigned to the new spalling material generated during the breaking process.

[0014] Step 9: Update the position of the boundary of the spalling material in the three-dimensional space grid based on the resultant force acting on the spalling material.

[0015] Step 10: Perform collision processing on the particles contained in the plasma, advance the current time step to the next time step, and return to execute step 2 until the three-dimensional simulation process of the Hall thruster ends.

[0016] In one implementation, determining the resultant force and charge change on the debris in the Hall thruster based on the physical processes occurring in the target particle ensemble relative to the debris boundary includes:

[0017] Based on the collisions between the target particle set and the boundary of the debris within the current time step, determine the charged particle bombardment force and neutral atom gradient force experienced by the debris.

[0018] Based on the number of collisions between ions in the target particle set and the exfoliated material within the current time step, and the number of physical processes between electrons in the target particle set and the exfoliated material, the charge change of the exfoliated material within the current time step is determined, which is used to determine the electromagnetic force on the exfoliated material.

[0019] The net force on the exfoliated material is determined based on the bombardment force of charged particles, the gradient force of neutral atoms, and the electromagnetic force.

[0020] In one implementation, a criterion for determining whether the flaking material has broken is used to determine whether it has broken. If it has broken, the amount of charge assigned to the new flaking material generated during the breaking process is determined.

[0021] Based on the attribute data of the ions in the target particle set and the collision cross section between the ions in the target particle set and the exfoliated material, the kinetic energy of the ions deposited per unit volume of the exfoliated material is determined.

[0022] If the kinetic energy of the ions is less than the critical breakage energy density of the exfoliated material, it is determined that the exfoliated material has not broken.

[0023] When the kinetic energy of the ions is greater than the critical fragmentation energy density of the exfoliated material, the fragmentation of the exfoliated material is determined. The new exfoliated material generated during the fragmentation process is tracked. The exfoliated material is defined by applying boundary conditions, and the resultant force, charge change and trajectory of all exfoliated material are tracked and calculated.

[0024] In one implementation, the kinetic energy of ions deposited per unit volume of the exfoliated material is determined based on the attribute data corresponding to ions in the target particle set and the collision cross-section between the ions in the target particle set and the exfoliated material, including:

[0025] The kinetic energy of ions deposited per unit volume of exfoliated material is determined using the following formula:

[0026] ;

[0027] in, This refers to the kinetic energy of ions deposited per unit volume of the exfoliated material. For ion mass. The ion number density, For the three-dimensional velocity vector of the ion, The collision cross section between ions and exfoliated material in the target particle set. For time step, The volume of the exfoliated material.

[0028] In one implementation, tracking and calculating changes in the charge of all exfoliated material includes:

[0029] In cases where it is determined that the exfoliated material has broken up, the amount of neutralized charge is determined based on the dynamic charge neutralization effect that occurs during the breaking up.

[0030] The difference between the net charge carried by the debris before it breaks down and the neutralized charge is taken as the distributable charge.

[0031] Based on the surface area and distributable charge of the fragments formed after the exfoliation material breaks down, the target charge amount to be distributed to the fragments is determined.

[0032] In one implementation, determining the charge allocated to the detached fragments based on the surface area and distributable charge of the fragments formed after the detachment material breaks down includes:

[0033] The amount of charge distributed on the detached fragments is determined using the following formula:

[0034] ;

[0035] For the first The amount of charge distributed among each detached fragment. For the first The surface area of ​​each flaked fragment The total surface area of ​​all the detached fragments. This refers to the net charge carried by the flaking material before it breaks apart. The portion of the charge neutralized during the fragmentation process by the opposite charge carried by the incident ions is denoted as the neutralized charge. The charge neutralization efficiency coefficient. This refers to the amount of charge that can be distributed.

[0036] In one implementation, updating the position of the spall boundary in the three-dimensional spatial grid based on the resultant force acting on the spall includes:

[0037] Determine the change in velocity of the exfoliated material based on the net force acting on it.

[0038] Based on the change in velocity, determine the updated three-dimensional velocity vector of the exfoliated material;

[0039] The spalling material is propelled according to the updated 3D velocity vector to obtain the location of the spalling material boundary in the 3D space grid.

[0040] Secondly, the present invention also provides a Hall thruster debris motion-plasmodynamics coupled simulation device, comprising:

[0041] The 3D modeling module is used to obtain the 3D spatial mesh corresponding to the Hall thruster. The 3D spatial mesh is generated by meshing based on the geometry of the Hall thruster.

[0042] The charge distribution determination module is used to determine the charge distribution corresponding to the three-dimensional spatial grid within the current time step based on the density of particles contained in the plasma in the Hall thruster and the amount of charge carried by the exfoliated material; wherein the exfoliated material is modeled as a three-dimensional thin sheet.

[0043] The electric field distribution determination module is used to solve for the electric field distribution corresponding to the three-dimensional spatial grid within the current time step based on the charge distribution.

[0044] The particle force analysis module is used to interpolate the electric field distribution based on the three-dimensional position coordinates of the particles contained in the plasma in the Hall thruster at the previous time step, so as to obtain the electromagnetic force on the particles.

[0045] The particle propulsion module is used to determine the three-dimensional position coordinates and three-dimensional velocity vector of a particle within the current time step based on the electromagnetic force acting on it.

[0046] The boundary processing module is used to determine the set of target particles that reach the geometric boundary in the three-dimensional space grid and the physical process that occurs therein, based on the three-dimensional position coordinates and three-dimensional velocity vector of the particles in the current time step; wherein, the geometric boundary includes at least the exfoliation boundary in the current time step;

[0047] The detachment force and charge analysis module is used to determine the resultant force and charge change of the detachment in the Hall thruster based on the physical processes that occur in the target particle set relative to the detachment boundary.

[0048] The breakage determination module is used to determine whether the spalling material has broken based on the spalling material breakage determination criteria, and to determine the amount of charge allocated to the new spalling material generated during the breakage process if breakage has occurred.

[0049] The spalling material pushing module is used to update the position of the spalling material boundary in the three-dimensional space mesh based on the resultant force acting on the spalling material;

[0050] The collision processing module is used to process the collisions between particles contained in the plasma, advance the current time step to the next time step, and return to the charge distribution determination module until the three-dimensional simulation process of the Hall thruster ends.

[0051] Thirdly, the present invention also provides an electronic device including a processor and a memory, the memory storing computer-executable instructions executable by the processor, the processor executing the computer-executable instructions to implement any of the methods provided in the first aspect.

[0052] Fourthly, the present invention also provides a computer-readable storage medium storing computer-executable instructions, which, when invoked and executed by a processor, cause the processor to implement any of the methods provided in the first aspect.

[0053] This invention provides a coupled simulation method for the motion of debris from a Hall thruster and plasma dynamics. Step 1: Obtain the three-dimensional spatial mesh corresponding to the Hall thruster. The three-dimensional spatial mesh is generated based on the geometry of the Hall thruster through mesh generation. Step 2: Determine the charge distribution corresponding to the three-dimensional spatial mesh within the current time step based on the particle density contained in the plasma of the Hall thruster and the charge carried by the debris. The debris is modeled as a three-dimensional thin sheet. Step 3: Solve for the electric field distribution corresponding to the three-dimensional spatial mesh within the current time step based on the charge distribution. Step 4: Interpolate the electric field distribution based on the three-dimensional position coordinates of the particles contained in the plasma of the Hall thruster in the previous time step to obtain the electromagnetic force experienced by the particles. Step 5: Determine the three-dimensional position coordinates and three-dimensional velocity vector of the particles within the current time step based on the electromagnetic force experienced by the particles. Step 6: Based on... The three-dimensional position coordinates and three-dimensional velocity vectors of the particles in the current time step are used to determine the target particle set that reaches the geometric boundary in the three-dimensional space grid and the physical process that occurs therein; wherein, the geometric boundary includes at least the spalling boundary in the current time step; Step 7, based on the physical process that occurs in the target particle set relative to the spalling boundary, the resultant force and charge change of the spalling in the Hall thruster are determined; Step 8, based on the spalling breakage judgment criterion, it is determined whether the spalling has broken, and if it has broken, the charge amount of the new spalling generated during the breakage process is determined; Step 9, the position of the spalling boundary in the three-dimensional space grid is updated according to the resultant force on the spalling; Step 10, collision processing is performed between the particles contained in the plasma, the current time step is advanced to the next time step, and Step 2 is returned to be executed until the three-dimensional simulation process of the Hall thruster ends. The above method establishes a three-dimensional velocity simulation model for the discharge process and spalling disturbance of the Hall thruster, obtains the motion and collision behavior of each particle in the Hall thruster plasma, and simulates the charge and matter exchange process between plasma and spalling through self-consistent solution of the spalling motion and plasma behavior evolution process, simulates the spalling trajectory, the spalling fragmentation process, and the discharge disturbance process, and conducts a high-fidelity study on the discharge disturbance induced by Hall thruster spalling. This invention effectively reduces the difference between the simulation results and the actual situation, thereby effectively enhancing the credibility and practicality of the simulation.

[0054] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings.

[0055] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0056] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0057] Figure 1 A flowchart illustrating a Hall thruster debris motion-plasmodynamics coupled simulation method provided in an embodiment of the present invention;

[0058] Figure 2 A technical framework diagram of a Hall thruster debris motion-plasmodynamics coupled simulation method provided in an embodiment of the present invention;

[0059] Figure 3 A schematic diagram of a Hall thruster spallation-plasma dynamics coupled simulation device provided in an embodiment of the present invention;

[0060] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0062] Currently, existing software cannot simultaneously obtain the trajectory of the spalled material and the evolution process induced by discharge disturbances, cannot accurately obtain the charge and mass exchange between the spalled material and the plasma, and fails to simulate the spalled material fragmentation and disturbance process, resulting in discrepancies between the simulation results and actual conditions. Therefore, this invention provides a coupled simulation method for the motion of spalled material and plasma dynamics in a Hall thruster, significantly improving simulation accuracy and thus effectively enhancing the reliability and practicality of the simulation.

[0063] To facilitate understanding of this embodiment, a detailed description of the Hall thruster spalling material motion-plasma dynamics coupled simulation method disclosed in this embodiment of the invention will be provided first. (See [link to relevant documentation]). Figure 1 The diagram shows a flowchart of a Hall thruster debris motion-plasmodynamics coupled simulation method, which mainly includes the following steps:

[0064] Step 1: Obtain the three-dimensional spatial mesh corresponding to the Hall thruster.

[0065] The three-dimensional spatial mesh is generated by meshing based on the geometry of the Hall thruster. Furthermore, this embodiment of the invention also performs three-dimensional modeling of the spalled material, thereby obtaining spalled material in the form of three-dimensional thin sheets.

[0066] Step 2: Determine the charge distribution corresponding to the three-dimensional spatial grid within the current time step based on the particle density of the plasma in the Hall thruster and the charge carried by the exfoliated material. The exfoliated material is modeled as a three-dimensional thin sheet.

[0067] Step 3: Based on the charge distribution, solve for the electric field distribution corresponding to the three-dimensional spatial grid within the current time step.

[0068] Step 4: Based on the three-dimensional position coordinates of the particles contained in the plasma in the Hall thruster at the previous time step, interpolate the electric field distribution to obtain the electromagnetic force on the particles.

[0069] Step 5: Determine the three-dimensional position coordinates and three-dimensional velocity vector of the particle within the current time step based on the electromagnetic force acting on it.

[0070] Step 6: Based on the three-dimensional position coordinates and three-dimensional velocity vector of the particles in the current time step, determine the set of target particles reaching the geometric boundary in the three-dimensional spatial grid and the physical process that occurs therein. The geometric boundary includes at least the exfoliation boundary in the current time step, and may also include the vacuum boundary, anode boundary, cathode boundary, and discharge channel wall boundary.

[0071] Step 7: Based on the physical processes occurring in the target particle set relative to the boundary of the debris, determine the resultant force and charge change of the debris in the Hall thruster.

[0072] Step 8: Determine whether the spalling material has broken based on the spalling material breakage judgment criteria, and if it has broken, determine the amount of charge allocated to the new spalling material generated during the breaking process.

[0073] Step 9: Update the position of the boundary of the spalled material in the three-dimensional space grid based on the resultant force acting on the spalled material.

[0074] Step 10: Perform collision processing on the particles contained in the plasma, advance the current time step to the next time step, and return to execute step 2 until the three-dimensional simulation process of the Hall thruster ends.

[0075] The Hall thruster spallation motion-plasma dynamics coupled simulation method provided in this invention establishes a three-dimensional velocity simulation model of the Hall thruster discharge process and spallation disturbance. It uses a combination of particle mesh method and Monte Carlo collision method to obtain the motion and collision behavior of each particle within the Hall thruster plasma. Furthermore, through self-consistent solution of the spallation motion and plasma behavior evolution process, it simulates the charge and matter exchange process between plasma and spallation, the spallation trajectory, the spallation fragmentation process, and the discharge disturbance process. This allows for high-fidelity research on the discharge disturbance mechanism induced by Hall thruster spallation. This invention effectively reduces the discrepancy between simulation results and actual conditions, thereby significantly enhancing the reliability and practicality of the simulation.

[0076] For ease of understanding, this invention provides a specific implementation of a Hall thruster debris motion-plasmodynamics coupled simulation method, see [link to relevant documentation]. Figure 2 The diagram shown illustrates a technical framework for a coupled simulation method of Hall thruster debris motion and plasma dynamics, including:

[0077] (a) Calculate the plasma particle density and count the charge carried by the exfoliated material to obtain the charge distribution.

[0078] In one implementation, the charge distribution corresponding to the three-dimensional spatial grid within the current time step is determined based on the particle density of the plasma in the Hall thruster and the target charge carried by the exfoliated material. The exfoliated material is modeled as a three-dimensional sheet. Specifically, the particle density is calculated, and particle parameters are deposited onto the grid using a cloud-in-cell (CIC) method. Simultaneously, the charge carried by the exfoliated material is deposited onto adjacent grid cells at the location of the exfoliated material; the charged particles of the plasma and the exfoliated material together determine the charge distribution.

[0079] (ii) Calculate the electric potential and electric field.

[0080] In one implementation, the electric field distribution corresponding to the three-dimensional spatial grid within the current time step is solved based on the charge distribution. Specifically, the induced magnetic field generated by particle motion in the Hall thruster is very small and can be ignored, while the applied magnetic field is much larger than the magnetic field generated by plasma coupling. Therefore, the magnetic field can be considered a static magnetic field, and the electric field can be solved using the Poisson equation during the calculation. The potential distribution is calculated based on the charge distribution, and the potential applied to the conductive electrodes is used as a constraint condition to solve a linear equation on the grid. By differentiating the potential distribution, the electric field at each grid point can be obtained.

[0081] (iii) Calculate all electromagnetic forces of the particle.

[0082] In one implementation, the electric field distribution is interpolated based on the three-dimensional position coordinates of the particles contained in the plasma within the Hall thruster at the previous time step to obtain the electromagnetic force acting on the particles. Specifically, a partially magnetized plasma model is used to improve computational efficiency. The physical basis of this model is that electrons have a small cyclotron radius, thus they are magnetized and constrained by a magnetic field; conversely, ions have a much larger cyclotron radius than their characteristic size, and their motion is almost unaffected by the magnetic field. Based on this, the magnetic force acting on electrons needs to be considered in the simulation, while the magnetic force acting on ions can be ignored. Within each time step, the solver, based on the electric field distribution calculated in the previous step, interpolates the field quantities at the grid nodes to each particle position, thereby determining the electromagnetic force acting on the particles.

[0083] (iv) Propulsion of particles.

[0084] In one implementation, the three-dimensional position coordinates and three-dimensional velocity vector of the particle are determined within the current time step based on the electromagnetic force acting on the particle. Specifically, within each time step, the new position and velocity information of the particle are calculated based on the newly obtained force acting on the particle. To simplify the computation, the leapfrog scheme is used to discretize the particle's acceleration under an electric field and its deflection under a magnetic field.

[0085] (v) Boundary condition processing, including the processing of particle and Hall thruster boundaries and spalling boundaries.

[0086] The system counts the particles that reach the set boundary interfaces and processes these particles according to the different boundary types. The following briefly describes the included boundary types and their processing methods:

[0087] (1) Vacuum boundary: The outer boundary of the computational domain, used to simulate the infinitely far region in the space environment. All types of particles are deleted when they cross this boundary.

[0088] (2) Anode boundary: When neutral atoms collide with this boundary, they are treated as diffuse reflection, while electrons and ions are treated as absorption.

[0089] (3) Cathode boundary: When neutral atoms collide with this boundary, they are treated as diffuse reflection, electrons are treated as specular reflection, and ions are treated as absorption.

[0090] (4) Boundary between the discharge channel wall and the spalling material: Since the spalling material originates from the sputtered material on the discharge channel wall, both materials share the same origin, and the boundary conditions should be treated the same. When particles reach such boundaries, neutral atoms undergo diffuse reflection, ions undergo absorption, and the charge is deposited onto the wall and the spalling material. Electrons will exhibit four different behaviors depending on the incident electron energy: absorption deposition, elastic reflection, bombardment of a new electron, and bombardment of two new electrons.

[0091] (vi) Calculate the total force on the exfoliated material based on the boundary behavior of the particles and the electromagnetic field, and update the charge on the exfoliated material.

[0092] In one implementation, the charged particle bombardment force and neutral atom gradient force on the exfoliated material are determined based on the collisions that occur between the target particle set and the boundary of the exfoliated material within the current time step; the charge change of the exfoliated material within the current time step is determined based on the number of collisions between ions in the target particle set and the exfoliated material, and the number of physical processes that occur between electrons in the target particle set and the exfoliated material within the current time step, in order to determine the electromagnetic force on the exfoliated material; and the resultant force on the exfoliated material is determined based on the charged particle bombardment force, the neutral atom gradient force, and the electromagnetic force.

[0093] Specifically, the collisions between neutral atoms, charged particles, and the exfoliated material within this time step are statistically analyzed to obtain the momentum exchange. The bombardment force from charged particles and the gradient force from neutral atoms on the exfoliated material are then calculated. The number of collisions between ions and the exfoliated material, and the number of each of the four processes involving electrons and the exfoliated material, are also statistically analyzed to determine the change in charge on the exfoliated material within this time step, updating the charge on the exfoliated material. Based on this charge and the updated electric and magnetic field distributions, the electromagnetic force on the exfoliated material is calculated. The vector sum of the bombardment force from charged particles, the atomic density gradient force, the electromagnetic force, and the magnetic field force is taken as the resultant force on the exfoliated material.

[0094] (vii) Determining whether the flaking material is broken.

[0095] In one implementation, the kinetic energy of ions deposited per unit volume of the exfoliated material is determined based on the attribute data of ions in the target particle set and the collision cross section between the ions in the target particle set and the exfoliated material. If the kinetic energy of the ions is less than the critical fragmentation energy density of the exfoliated material, it is determined that the exfoliated material has not fragmented. If the kinetic energy of the ions is greater than the critical fragmentation energy density of the exfoliated material, it is determined that the exfoliated material has fragmented. New exfoliated material generated during the fragmentation process is tracked. The exfoliated material is defined by applying boundary conditions, and the resultant force, charge change and trajectory of all exfoliated material are tracked and calculated.

[0096] Specifically, during its movement, the exfoliated material is bombarded by high-energy ions, and the resulting kinetic energy deposition may lead to stress concentration within the exfoliated material, thereby causing it to break apart. To quantitatively describe this process, a kinetic energy deposition density threshold criterion is introduced:

[0097] ;

[0098] in, This refers to the kinetic energy of ions deposited per unit volume of the exfoliated material. For ion mass. The ion number density, For the three-dimensional velocity vector of the ion, The collision cross section between ions and exfoliated material in the target particle set. For time step, The volume of the exfoliated material.

[0099] The core physical idea behind the criterion is that macroscopic fragmentation will occur when the kinetic energy of ions deposited within a unit volume of exfoliated material exceeds the material's critical binding energy density. In actual physical processes, fragmentation may begin with microscopic cracks present in the exfoliated material and is random. To simulate the fragmentation disturbance, an averaged threshold is used in the simulation for determination.

[0100] Furthermore, when it is determined that the spalling material has broken, the amount of neutralized charge is determined based on the dynamic charge neutralization effect that occurs when the spalling material breaks; the difference between the net charge carried by the spalling material before breaking and the amount of neutralized charge is taken as the amount of distributable charge; and the target amount of charge allocated to the spalling fragments is determined based on the surface area and distributable charge of the spalling fragments (i.e., new spalling material) formed after the spalling material breaks.

[0101] Specifically, the charge redistribution at the moment of fragmentation is a complex process involving charge conservation and dynamic neutralization. The simulation establishes a post-fragmentation charge distribution mechanism to accurately describe the initial charged state of each fragment. Under the premise of obeying the law of charge conservation, the fragments are distributed according to their surface area. The charge distribution formula is as follows:

[0102] ;

[0103] in, For the first The charge assigned to each fragment For the first The surface area of ​​each flaked fragment The total surface area of ​​all the detached fragments. It is the ratio of the surface area of ​​this fragment to the total surface area of ​​all fragments, i.e., its allocation weight. It is the net charge carried by the flaking material before it breaks apart. This represents the portion of the charge neutralized by the opposite charge carried by the incident ions during the violent collision that causes the fragmentation; it is denoted as the neutralized charge. This describes the dynamic charge neutralization effect that occurs during fragmentation, denoted as the distributable charge. When exfoliated material is bombarded by high-energy ions and fragments, a portion of the ionic charge neutralizes the original charge of the exfoliated material. The charge neutralization efficiency coefficient is used to describe this process. The efficiency of this process is quantified by the collision energy and the dielectric properties of the exfoliated material, and is calibrated experimentally, typically ranging from 0.5 to 0.9.

[0104] (viii) Promote the movement of detached material and update the location of detached material boundary conditions.

[0105] In one implementation, the velocity change of the exfoliated material is determined based on the resultant force acting on it; the updated three-dimensional velocity vector of the exfoliated material is determined based on the velocity change; and the exfoliated material is propelled according to the updated three-dimensional velocity vector to obtain the position of the exfoliated material boundary in the three-dimensional space grid.

[0106] Specifically, based on the calculated net force acting on the debris, the change in the debris's velocity is calculated to obtain the new velocity of the debris. This new velocity propels the debris to a new position, updating the debris's position, velocity, and the location of its boundary conditions. If the debris breaks, each fragment will be propelled independently.

[0107] (ix) Collision handling, including collisions between particles such as elastic, ionization, excitation, and charge exchange collisions. At each given time step... In this process, it is necessary to determine the collisions that occur for each particle. Inside the thruster, there are various collision scenarios between particles. The frequency of these collisions is controlled by the collision cross-section. To save computation, a Monte Carlo process using empty collisions is employed, eliminating the need to traverse all particles for collision selection. This embodiment of the invention considers the following types of collisions:

[0108] (1) Collisions between electrons and atoms, including elastic collisions, ionization, and excitation collisions; (2) Collisions between ions and atoms, including momentum exchange collisions and charge exchange collisions; (3) Momentum exchange collisions between atoms; (4) Recombination processes between electrons and ions.

[0109] After completing (nine), the cycle repeats from (one).

[0110] In summary, the embodiments of the present invention have the following advantages:

[0111] (1) The embodiments of the present invention establish a three-dimensional model of the exfoliated material, which is closer to the real situation than the ring-shaped exfoliated material in the two-dimensional axisymmetric simulation, and eliminates the error caused by overestimating the volume of the exfoliated material.

[0112] (2) The embodiments of the present invention establish the process of material and charge exchange between the exfoliated material and the plasma field, realize the self-consistent solution of the change of charge carried by the exfoliated material, reflect the influence of the exfoliated material on the potential distribution with higher fidelity, and simulate the movement trajectory of the exfoliated material with higher accuracy.

[0113] (3) The embodiments of the present invention establish a criterion for determining the breakage of the exfoliated material, simulate the breakage process of the exfoliated material during movement, and realize the evolution of multiple exfoliated material fragments on the discharge disturbance process.

[0114] (4) In this embodiment of the invention, a joint simulation of the movement of the spalling material and the discharge disturbance is established to achieve a self-consistent solution for the movement of the spalling material and the change of charge, and at the same time obtain the evolution process of the discharge disturbance, so as to realize the analysis of the coupled process of the spalling material affecting the plasma distribution and the plasma distribution affecting the movement of the spalling material. Previously, the software treated the spalling material as a static boundary condition, which could not reflect the influence of the spalling material's trajectory on the discharge disturbance.

[0115] Based on the foregoing embodiments, this invention provides a Hall thruster debris motion-plasma dynamics coupled simulation device, see [link to relevant documentation]. Figure 3 The diagram shows a structural schematic of a Hall thruster debris motion-plasmodynamics coupled simulation device, which mainly includes the following parts:

[0116] The 3D modeling module 302 is used to obtain the 3D spatial mesh corresponding to the Hall thruster. The 3D spatial mesh is generated by meshing based on the geometry of the Hall thruster.

[0117] The charge distribution determination module 304 is used to determine the charge distribution corresponding to the three-dimensional spatial grid in the current time step based on the density of particles contained in the plasma in the Hall thruster and the amount of charge carried by the exfoliated material; wherein the exfoliated material is modeled as a three-dimensional thin sheet.

[0118] The electric field distribution determination module 306 is used to solve the electric field distribution corresponding to the three-dimensional spatial grid in the current time step based on the charge distribution;

[0119] The particle force analysis module 308 is used to interpolate the electric field distribution based on the three-dimensional position coordinates of the particles contained in the plasma in the Hall thruster at the previous time step, so as to obtain the electromagnetic force on the particles.

[0120] The particle propulsion module 310 is used to determine the three-dimensional position coordinates and three-dimensional velocity vector of a particle in the current time step based on the electromagnetic force acting on the particle.

[0121] The boundary processing module 312 is used to determine the set of target particles that reach the geometric boundary in the three-dimensional space grid and the physical process that occurs therein, based on the three-dimensional position coordinates and three-dimensional velocity vector of the particles in the current time step; wherein, the geometric boundary includes at least the exfoliation boundary in the current time step.

[0122] The force and charge analysis module 314 for exfoliated material is used to determine the resultant force and charge change of the exfoliated material in the Hall thruster based on the physical process that occurs in the target particle set relative to the boundary of the exfoliated material.

[0123] The breakage determination module 316 is used to determine whether the spalling material has broken based on the spalling material breakage determination criteria, and to determine the amount of charge allocated to the new spalling material generated during the breakage process if breakage occurs.

[0124] The spalling material pushing module 318 is used to update the position of the spalling material boundary in the three-dimensional space grid according to the resultant force on the spalling material;

[0125] The collision processing module 320 is used to process the collisions between particles contained in the plasma, advance the current time step to the next time step, and return to the charge distribution determination module until the three-dimensional simulation process of the Hall thruster ends.

[0126] The Hall thruster spalling motion-plasma dynamics coupled simulation device provided in this invention establishes a three-dimensional velocity simulation model for the Hall thruster discharge process and spalling disturbance, obtains the motion and collision behavior of each particle in the Hall thruster plasma, and simulates the charge and matter exchange process between plasma and spalling through self-consistent solution of the spalling motion and plasma behavior evolution process, simulates the spalling trajectory, the spalling fragmentation process, and the discharge disturbance process, and conducts high-fidelity research on the discharge disturbance induced by Hall thruster spalling. This invention effectively reduces the difference between simulation results and actual situation, thereby effectively enhancing the credibility and practicality of the simulation.

[0127] In one embodiment, the stress and charge analysis module 314 for exfoliated material is specifically used for:

[0128] Based on the collisions between the target particle set and the boundary of the debris within the current time step, determine the charged particle bombardment force and neutral atom gradient force experienced by the debris.

[0129] Based on the number of collisions between ions in the target particle set and the exfoliated material within the current time step, and the number of physical processes between electrons in the target particle set and the exfoliated material, the charge change of the exfoliated material within the current time step is determined, which is used to determine the electromagnetic force on the exfoliated material.

[0130] The net force on the exfoliated material is determined based on the bombardment force of charged particles, the gradient force of neutral atoms, and the electromagnetic force.

[0131] In one embodiment, the breakage determination module 316 is specifically used for:

[0132] Based on the attribute data of the ions in the target particle set and the collision cross section between the ions in the target particle set and the exfoliated material, the kinetic energy of the ions deposited per unit volume of the exfoliated material is determined.

[0133] If the kinetic energy of the ions is less than the critical breakage energy density of the exfoliated material, it is determined that the exfoliated material has not broken.

[0134] When the kinetic energy of the ions is greater than the critical breakage energy density of the exfoliated material, it is determined that the exfoliated material has broken. The new exfoliated material generated during the breaking process is tracked. The exfoliated material is defined by applying boundary conditions to it, and the resultant force, charge change and trajectory of all the exfoliated material are tracked and calculated.

[0135] In one embodiment, the breakage determination module 316 is specifically used for:

[0136] The kinetic energy of ions deposited per unit volume of exfoliated material is determined using the following formula:

[0137] ;

[0138] in, This refers to the kinetic energy of ions deposited per unit volume of the exfoliated material. For ion mass. The ion number density, For the three-dimensional velocity vector of the ion, The collision cross section between ions and exfoliated material in the target particle set. For time step, The volume of the exfoliated material.

[0139] In one embodiment, the breakage determination module 316 is specifically used for:

[0140] In cases where it is determined that the exfoliated material has broken up, the amount of neutralized charge is determined based on the dynamic charge neutralization effect that occurs during the breaking up.

[0141] The difference between the net charge carried by the debris before it breaks down and the neutralized charge is taken as the distributable charge.

[0142] Based on the surface area and distributable charge of the fragments formed after the exfoliation material breaks down, the target charge amount to be distributed to the fragments is determined.

[0143] In one embodiment, the breakage determination module 316 is specifically used for:

[0144] The amount of charge distributed on the exfoliated fragments is determined according to the following formula:

[0145] ;

[0146] For the first The amount of charge distributed among each detached fragment. For the first The surface area of ​​each flaked fragment The total surface area of ​​all the detached fragments. This refers to the net charge carried by the flaking material before it breaks apart. The portion of the charge neutralized during the fragmentation process by the opposite charge carried by the incident ions is denoted as the neutralized charge. The charge neutralization efficiency coefficient. This refers to the amount of charge that can be distributed.

[0147] In one embodiment, the shed material pushing module 318 is specifically used for:

[0148] Determine the change in velocity of the exfoliated material based on the net force acting on it.

[0149] Based on the change in velocity, determine the updated three-dimensional velocity vector of the exfoliated material;

[0150] The spalling material is propelled according to the updated 3D velocity vector to obtain the location of the spalling material boundary in the 3D space grid.

[0151] The device provided in this embodiment of the invention has the same implementation principle and technical effect as the aforementioned method embodiment. For the sake of brevity, any parts not mentioned in the device embodiment can be referred to the corresponding content in the aforementioned method embodiment.

[0152] This invention provides an electronic device, specifically, the electronic device includes a processor and a memory; the memory stores a computer program, which, when run by the processor, executes the method described in any of the above embodiments.

[0153] Figure 4 The present invention provides a schematic diagram of the structure of an electronic device 100, which includes a processor 40, a memory 41, a bus 42 and a communication interface 43. The processor 40, the communication interface 43 and the memory 41 are connected through the bus 42. The processor 40 is used to execute executable modules, such as computer programs, stored in the memory 41.

[0154] The memory 41 may include high-speed random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Communication between this system network element and at least one other network element is achieved through at least one communication interface 43 (which can be wired or wireless), such as the Internet, wide area network, local area network, metropolitan area network, etc.

[0155] Bus 42 can be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 4 The symbol is represented by a single double-headed arrow, but this does not mean that there is only one bus or one type of bus.

[0156] The memory 41 is used to store programs. After receiving an execution instruction, the processor 40 executes the program. The method executed by the device for defining the flow process disclosed in any of the foregoing embodiments of the present invention can be applied to the processor 40 or implemented by the processor 40.

[0157] Processor 40 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of processor 40 or by instructions in software form. Processor 40 can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this invention can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory 41. The processor 40 reads the information in memory 41 and, in conjunction with its hardware, completes the steps of the above method.

[0158] The computer program product of the readable storage medium provided in the embodiments of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the foregoing method embodiments. For specific implementation, please refer to the foregoing method embodiments, which will not be repeated here.

[0159] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0160] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A coupled simulation method for the motion of Hall thruster debris and plasma dynamics, characterized in that, include: Step 1: Obtain the three-dimensional spatial mesh corresponding to the Hall thruster. The three-dimensional spatial mesh is generated by meshing based on the geometry of the Hall thruster. Step 2: Determine the charge distribution corresponding to the three-dimensional spatial grid within the current time step based on the density of particles contained in the plasma in the Hall thruster and the amount of charge carried by the exfoliated material; wherein, the exfoliated material is modeled as a three-dimensional thin sheet. Step 3: Based on the charge distribution, solve for the electric field distribution corresponding to the three-dimensional spatial grid in the current time step; Step 4: Based on the three-dimensional position coordinates of the particles contained in the plasma in the Hall thruster at the previous time step, interpolate the electric field distribution to obtain the electromagnetic force on the particles. Step 5: Determine the three-dimensional position coordinates and three-dimensional velocity vector of the particle in the current time step based on the electromagnetic force acting on it. Step 6: Based on the three-dimensional position coordinates and three-dimensional velocity vector of the particles in the current time step, determine the set of target particles that reach the geometric boundary in the three-dimensional spatial grid and the physical process that occurs therein; wherein, the geometric boundary includes at least the exfoliation boundary in the current time step. Step 7: Determine the resultant force and charge change of the debris in the Hall thruster based on the physical process that occurs in the target particle set relative to the boundary of the debris. Step 8: Determine whether the flaking material has broken based on the flaking material breakage judgment criteria, and if it has broken, determine the amount of charge assigned to the new flaking material generated during the breaking process. Step 9: Update the position of the boundary of the exfoliated material in the three-dimensional space grid based on the resultant force on all the exfoliated material after step 8. Step 10: Perform collision processing on the particles contained in the plasma, advance the current time step to the next time step, and return to execute step 2 until the three-dimensional simulation process of the Hall thruster ends.

2. The Hall thruster spalling material motion-plasmodynamics coupled simulation method according to claim 1, characterized in that, Based on the physical processes occurring in the target particle ensemble relative to the boundary of the debris, the resultant force and charge change acting on the debris in the Hall thruster are determined, including: Based on the collisions that occur between the target particle set and the boundary of the exfoliated material within the current time step, determine the charged particle bombardment force and neutral atom gradient force experienced by the exfoliated material. Based on the number of collisions between ions in the target particle set and the exfoliated material within the current time step, and the number of physical processes between electrons in the target particle set and the exfoliated material, the charge change of the exfoliated material within the current time step is determined, in order to determine the electromagnetic force on the exfoliated material. The resultant force acting on the exfoliated material is determined based on the bombardment force of the charged particles, the gradient force of the neutral atoms, and the electromagnetic force.

3. The Hall thruster spalling material motion-plasmodynamics coupled simulation method according to claim 1, characterized in that, Based on the criteria for determining whether the flaking material has broken, the method determines whether the flaking material has broken, and if it has broken, determines the amount of charge assigned to the new flaking material generated during the breaking process, including: Based on the attribute data of the ions in the target particle set and the collision cross section between the ions in the target particle set and the exfoliated material, the kinetic energy of the ions deposited per unit volume of the exfoliated material is determined. If the kinetic energy of the ions is less than the critical breakage energy density of the exfoliated material, it is determined that the exfoliated material has not broken. When the kinetic energy of the ions is greater than the critical breakage energy density of the exfoliated material, it is determined that the exfoliated material has broken. The new exfoliated material generated during the breaking process is tracked. The exfoliated material is defined by applying boundary conditions to it, and the resultant force, charge change and trajectory of all the exfoliated material are tracked and calculated.

4. The Hall thruster spalling material motion-plasmodynamics coupled simulation method according to claim 3, characterized in that, Based on the attribute data corresponding to the ions in the target particle set and the collision cross-section between the ions in the target particle set and the exfoliated material, the kinetic energy of the ions deposited per unit volume of the exfoliated material is determined, including: The kinetic energy of the ions deposited per unit volume of the exfoliated material is determined using the following formula: ； in, This refers to the kinetic energy of the ions deposited per unit volume of the exfoliated material. For ion mass, The ion number density For the three-dimensional velocity vector of the ion, The collision cross section between the ions in the target particle set and the exfoliated material. For time step, The volume of the exfoliated material.

5. The Hall thruster spalling material motion-plasmodynamics coupled simulation method according to claim 3, characterized in that, Track and calculate changes in the charge of all said exfoliated material, including: If it is determined that the exfoliated material has broken, the amount of neutralized charge is determined based on the dynamic charge neutralization effect that occurs when the breaking occurs; The difference between the net charge carried by the exfoliated material before it is broken and the neutralized charge is taken as the distributable charge. The amount of charge allocated to the new exfoliated material is determined based on the surface area of ​​the new exfoliated material formed after the exfoliated material is broken and the amount of charge that can be allocated.

6. The Hall thruster spalling material motion-plasmodynamics coupled simulation method according to claim 5, characterized in that, Based on the surface area of ​​the new debris formed after the debris is broken and the amount of distributable charge, the amount of charge distributed to the new debris is determined, including: The amount of charge assigned to the new exfoliated material is determined according to the following formula: ； For the first The amount of charge assigned to each new exfoliated material. For the first The new surface area of ​​the exfoliated material. The total surface area of ​​all the new exfoliated material. This refers to the net charge carried by the flaking material before it breaks apart. The portion of the charge neutralized during the fragmentation process by the opposite charge carried by the incident ions is denoted as the neutralized charge. The charge neutralization efficiency coefficient. This refers to the amount of charge that can be distributed.

7. The Hall thruster spalling material motion-plasmodynamics coupled simulation method according to claim 1, characterized in that, The position of the boundary of the exfoliated material in the three-dimensional space grid is updated based on the resultant force acting on the exfoliated material, including: Based on the resultant force acting on the exfoliated material, determine the corresponding change in velocity of the exfoliated material; Based on the change in velocity, the updated three-dimensional velocity vector of the exfoliated material is determined; The exfoliated material is propelled according to the updated three-dimensional velocity vector to determine the location of the exfoliated material boundary within the three-dimensional spatial grid.

8. A Hall thruster-plasma dynamics coupled simulation device, characterized in that, include: A 3D modeling module is used to obtain the 3D spatial mesh corresponding to the Hall thruster. The 3D spatial mesh is generated by meshing based on the geometry of the Hall thruster. The charge distribution determination module is used to determine the charge distribution corresponding to the three-dimensional spatial grid in the current time step based on the density of particles contained in the plasma in the Hall thruster and the amount of charge carried by the exfoliated material; wherein the exfoliated material is modeled as a three-dimensional thin sheet. The electric field distribution determination module is used to solve for the electric field distribution corresponding to the three-dimensional spatial grid in the current time step based on the charge distribution. The particle force analysis module is used to interpolate the electric field distribution based on the three-dimensional position coordinates of the particles contained in the plasma in the Hall thruster at the previous time step, so as to obtain the electromagnetic force on the particles. The particle propulsion module is used to determine the three-dimensional position coordinates and three-dimensional velocity vector of the particle in the current time step based on the electromagnetic force acting on the particle. The boundary processing module is used to determine the set of target particles that reach the geometric boundary of the three-dimensional spatial grid and the physical process that occurs therein, based on the three-dimensional position coordinates and three-dimensional velocity vector of the particles in the current time step; wherein, the geometric boundary includes at least the exfoliation boundary in the current time step; The detachment force and charge analysis module is used to determine the resultant force and charge change of the detachment in the Hall thruster based on the physical process that occurs in the target particle set relative to the detachment boundary. The breakage determination module is used to determine whether the flaking material has broken based on the flaking material breakage determination criteria, and to determine the amount of charge allocated to the new flaking material generated during the breakage process if breakage occurs. The spalling material pushing module is used to update the position of the spalling material boundary in the three-dimensional space grid based on the resultant force of all the spalling materials after the breakage determination module has been executed; The collision processing module is used to process the collisions between the particles contained in the plasma, advance the current time step to the next time step, and return to execute the charge distribution determination module until the three-dimensional simulation process of the Hall thruster ends.

9. An electronic device, characterized in that, The method includes a processor and a memory, the memory storing computer-executable instructions executable by the processor, the processor executing the computer-executable instructions to implement the method of any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions that, when invoked and executed by a processor, cause the processor to perform the method according to any one of claims 1 to 7.

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