A solps simulation method suitable for variable specific impulse magnetic plasma electric propulsion device

Abstract

The present application relates to the technical field of plasma physics simulation, and particularly relates to a SOLPS simulation method suitable for a variable specific impulse magnetoplasmadynamic electric propulsion device.The technical scheme comprises the following steps: parameter acquisition, acquiring simulation parameters of the electric propulsion device; file generation, generating input files required for SOLPS simulation through an external program based on the simulation parameters, including device geometry files, fluid grid files, power source files and particle source files; SOLPS calculation, importing the input files into a SOLPS program, generating a calculation grid by the SOLPS program and performing plasma simulation calculation.The present application solves the adaptability problem of the application of the SOLPS program in the variable specific impulse magnetoplasmadynamic linear electric propulsion device, realizes end-to-end integration from parameter input to result visualization, can accurately describe energy deposition distribution, and significantly improves the accuracy and efficiency of simulation.

Description

Technical Field

[0001] This invention relates to the field of plasma physics simulation technology, and in particular to a SOLPS simulation method applicable to variable specific impulse magneto-plasma electric propulsion devices. Background Technology

[0002] With the development of human space technology and the deepening of deep space exploration missions, future frequent and long-distance space missions have created an urgent need for high-performance space propulsion systems. Compared with traditional chemical propulsion that relies on the combustion of chemical fuels, electric propulsion technology generates and accelerates plasma to obtain thrust, achieving high specific impulse. This significantly reduces propellant load and improves the payload ratio of spacecraft, making it a key development direction in the field of deep space exploration. Among the many electric propulsion schemes, the Variable Specific Impulse Magnetoplasma Rocket (VASIMR), as an advanced high-power electrodeless electric propulsion device, is widely recognized as one of the most promising next-generation deep space propulsion technologies due to its outstanding advantages such as high and adjustable specific impulse, high thrust density, and long lifespan.

[0003] The VASIMR propulsion system typically consists of a three-stage structure: a helical wave ionization source, an ion cyclotron resonance heating (ICRH) unit, and a magnetic nozzle. Its working principle is as follows: First, a high-density plasma is generated by efficiently ionizing the working gas using a helical wave; then, the ICRH selectively heats the ions, giving them high energy; finally, the high-energy ions are ejected at high speed through the expanding magnetic nozzle, converting their cyclotron energy into directional axial kinetic energy, thus generating thrust. In this process, the efficiency of plasma generation, heating, and transport between the three stages directly determines the final performance of the propulsion system (such as thrust and specific impulse). Therefore, accurately studying the plasma behavior within the system is crucial for performance optimization.

[0004] However, at the experimental level, the extreme environments inside the VASIMR device, such as strong magnetic fields and high-temperature, high-pressure plasma, pose significant challenges to direct and comprehensive physical diagnostics, including high technical difficulty, high cost, and the risk of equipment damage. This makes numerical simulation an indispensable and important tool for studying its internal physical processes.

[0005] The SOLPS (Scrape-Off Layer Plasma Simulation) software suite is a two-dimensional multifluidic code widely used internationally for simulating the boundary plasma physics of tokamak devices. It possesses mature advantages in handling plasma and neutral particle transport, chemical reactions, and radiation processes under complex magnetic field configurations. Theoretically, by customizing external source terms, the SOLPS program can accurately describe the energy deposition distribution of helical waves and ICRH in VASIMR, thus providing a powerful simulation tool for studying plasma transport processes during its two-stage heating coupling.

[0006] Although the SOLPS program is powerful, its core design and input file format are primarily geared towards toroidal tokamak configurations. When applied to linear VASIMR devices, significant compatibility challenges arise.

[0007] Mesh generation is challenging: SOLPS calculations rely on pre-generated, structured meshes that conform to the magnetic surface. For linear devices, the Grad-Shafranov equations need to be solved independently based on the coil currents to obtain the magnetic flux distribution, and then the fluid mesh needs to be generated accordingly. This crucial step is not something that most commonly used versions of SOLPS can perform on their own.

[0008] The source term setup is complex: the power deposition distribution of helical waves and ICRH in VASIMR is complex. It is necessary to manually generate source files that conform to the SOLPS input format based on experimental data or the results of other wave simulation programs. The process is tedious and prone to errors.

[0009] The process is not integrated: the entire simulation process (including geometric modeling, mesh generation, source term setting, computation initiation, and post-processing) is fragmented into multiple independent manual operation steps, and a standardized, automated process for linear electric propulsion devices has not yet been formed. This not only greatly reduces research efficiency and prolongs the design cycle, but also introduces uncertainty into the accuracy and repeatability of simulation results.

[0010] In summary, there is an urgent need in this field to develop a dedicated simulation method based on the SOLPS program specifically for variable specific impulse magneto-plasma electric propulsion devices, in order to overcome the shortcomings of existing technologies such as poor adaptability and cumbersome processes, and to provide reliable and efficient technical support for the rapid performance evaluation and optimized design of such high-performance propulsion devices. This application proposes an SOLPS simulation method applicable to variable specific impulse magneto-plasma electric propulsion devices. Summary of the Invention

[0011] The purpose of this invention is to address the problem in the background art that the core design and input file format of the SOLPS program are mainly designed for toroidal tokamak configurations, which face significant adaptability challenges when applied to linear VASIMR devices. This invention proposes a SOLPS simulation method suitable for variable specific impulse magneto-plasma electric propulsion devices.

[0012] The technical solution of the present invention: A SOLPS simulation method applicable to variable specific impulse magneto-plasma electric propulsion devices, comprising the following steps:

[0013] Parameter acquisition: Obtain the simulated parameters of the electric propulsion device;

[0014] File generation: Based on the simulation parameters, an external program generates the input files required for SOLPS simulation, including device geometry files, fluid mesh files, power source files, and particle source files.

[0015] SOLPS calculation involves importing the input file into the SOLPS program, which then generates a computational grid and performs plasma simulation calculations.

[0016] Post-processing involves exporting the SOLPS calculation output data to external programs for data parsing and visualization.

[0017] Optionally, the simulation parameters include device parameters, grid setting parameters, and wave energy deposition distribution parameters.

[0018] Optional,

[0019] The device parameters include the device's geometric dimensions, coil dimensions, and current.

[0020] The grid setting parameters include the grid radial coordinate range, axial coordinate range, and resolution;

[0021] The wave energy deposition distribution parameters include total electron heating power, total ion heating power, total particle flux, and distribution function.

[0022] Optionally, the wave energy deposition distribution parameters can be obtained by fitting the radial electron density and temperature profile corresponding to helical wave heating or ion cyclotron heating in the experiment, or by obtaining the calculation results of the multiphysics coupling simulation platform (COMSOL Multiphysics, COMSOL).

[0023] Optionally, the specific process for generating the device geometry file and fluid mesh file in the file generation includes: establishing a reference coordinate system based on the axisymmetric characteristics of the linear electric propulsion device, generating a SOLPS-readable device geometry file (.ogr), calculating the magnetic flux distribution based on the coil parameters, and generating a quadrilateral mesh for SOLPS fluid calculation based on this.

[0024] Optionally, the specific process for generating the quadrilateral mesh includes:

[0025] Read the coil turns, current and coordinate information, and calculate the current density across the coil cross section;

[0026] The magnetic flux distribution, as well as the radial and axial magnetic field strengths, were obtained by calculating the Grad-Shafranov equations.

[0027] Generate a quadrilateral mesh based on the mesh setting parameters, and extract the radial coordinate R and axial coordinate Z of the mesh;

[0028] The mesh volume is calculated using the principle of axisymmetry: dV = 2πR·dR·dZ.

[0029] Optionally, the specific process for generating the power source file and particle source file in the file generation includes: generating the radial and axial distributions of the power source and particle source based on wave energy deposition distribution parameters and fluid mesh, and exporting and saving them as SOLPS input format files.

[0030] Optionally, the specific process for generating the power source and particle source files includes:

[0031] a. By analyzing the radial electron density and temperature profiles corresponding to helical wave heating or ion cyclotron heating in the experiment, the distribution information is obtained, and the source distribution is represented by a Gaussian distribution function:

[0032]

[0033]

[0034]

[0035]

[0036] Among them, S R,helicon S Z,helicon Power density distributions are divided into radial and axial helical waves, S R,ICRH S Z,ICRH The power density distribution of ion cyclotron heating is divided into radial and axial distributions, where R and Z are the radial and axial coordinates of a quadrilateral grid. , The coordinates of the center position of the power density distribution of the radial and axial spiral waves are divided into radial and axial spiral wave power density distributions. , The coordinates of the center position of the ion cyclotron heating power density distribution are divided into radial and axial. , The power density distribution width parameters are divided into radial and axial spiral waves. , The power density distribution width parameter is divided into radial and axial ion cyclotron heating.

[0037] b. Depending on the experimental conditions, a single-peak Gaussian distribution can be selected, or Gaussian linear superposition can be performed on the radial and axial sides respectively. Then, the corresponding radial and axial distribution functions are multiplied together and multiplied by the grid volume dV to obtain the two-dimensional distribution of the initial source volume density.

[0038] c. Multiply the initial two-dimensional source volume density distribution by the total power or particle flux to obtain the actual two-dimensional volume density distribution;

[0039] d. Based on the classification of electronic power, ion power, and particle source, the two-dimensional source volume density distributions of helical wave heating and ion cyclotron heating are added together, and the one-dimensional source volume density distributions of radial and axial directions are extracted.

[0040] e. Normalize the axial one-dimensional distribution, map the axial coordinates to the axial grid index or normalized connection length, and export and save it as the SOLPS external source input file b2.sources.profile;

[0041] f. When the wave energy deposition distribution is obtained through other wave propagation simulation programs, it is axially normalized according to the steps above to generate b2.sources.profile.

[0042] Optionally, the post-processing steps include:

[0043] The SOLPS official open-source MATLAB scripts are used to read quadrilateral mesh data files, triangular mesh data files, and data files that evolve over time.

[0044] The data dimensions are analyzed, and graphs are generated and saved based on quadrilateral and triangular grid coordinates.

[0045] Compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0046] By generating structured meshes and geometric files suitable for the magnetic field of linear electric propulsion devices through an external preprocessing program, the inherent limitation of most versions of the SOLPS program being native to toroidal tokamak configurations and unable to be directly used for linear devices is overcome.

[0047] The system integrates device parameters, magnetic field calculations, mesh generation, and source term settings into a unified workflow, automatically generating the geometric files, mesh files, and source distribution files required for SOLPS calculations, replacing the tedious and error-prone manual preparation method.

[0048] A power source generation method based on experimental fitting or wave simulation program results is provided, which can accurately describe the two-dimensional energy deposition distribution of helical wave and ion cyclotron resonance heating in the device, laying the foundation for accurate calculation of thrust and specific impulse.

[0049] By seamlessly integrating input file preparation, SOLPS computation kernel, and data post-processing, an end-to-end solution from parameter input to result visualization is built, avoiding data inconsistencies and operational complexity caused by switching between different software platforms.

[0050] By integrating and automating processes, researchers have significantly reduced the time spent on document preparation, format conversion, and data extraction, as well as human error, thus shortening the overall design and analysis cycle.

[0051] This invention solves the compatibility problem of SOLPS programs in variable specific impulse magneto-plasma linear electric propulsion devices by constructing a dedicated and automated simulation process. It achieves end-to-end integration from parameter input to result visualization, accurately describes energy deposition distribution, and significantly improves the accuracy and efficiency of the simulation. Attached Figure Description

[0052] Figure 1 A flowchart of a SOLPS simulation method applicable to variable specific impulse magneto-plasma electric propulsion devices;

[0053] Figure 2 This is a block diagram of the MATLAB software integration system.

[0054] Figure 3 Workflow diagram for preparing SOLPS input files;

[0055] Figure 4 Workflow diagram for the data processing and visualization module. Detailed Implementation

[0056] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0057] Example

[0058] like Figure 1 As shown, the present invention proposes a SOLPS simulation method applicable to variable specific impulse magneto-plasma electric propulsion devices, and its overall flowchart is as follows. Figure 1 As shown, the process includes the following steps: S1, input parameter reading; S2, fluid mesh generation; S3, SOLPS input file generation; S4, SOLPS calculation; S5, data processing and visualization. Specifically, step S2 generates the device geometry file and a quadrilateral fluid mesh, the former being converted into the device's inner wall within the SOLPS program; step S3 generates the wave energy deposition distribution file b2.sources.profile; and step S4 is the SOLPS program calculation, including the generation of a triangular neutral particle mesh within the program and program execution.

[0059] like Figure 2 As shown, this invention is based on MATLAB software and utilizes its graphical user interface (GUI) to design an interactive interface and an integrated module to implement the above steps. This module mainly includes a SOLPS input file preparation module and a data processing and visualization module. This module is used to generate the core files required for SOLPS calculations and process the raw data after calculations. The former is generated by... Figure 1 The process consists of steps S2 and S3.

[0060] Furthermore, such as Figure 3The diagram shows the SOLPS input file preparation module, which is used to generate the device geometry file, fluid mesh file, and power deposition source file required for SOLPS simulation. The specific steps are as follows: First, input the device geometry parameters, select the device cross-section using axisymmetry, and input the coordinates of each point on the inner wall of the device within the cross-section; input the coordinates of each point on the magnetic field coil cross-section based on the geometric coordinate system, then input the coil current and number of turns, input the mesh information to be generated, including the mesh region (radial and axial coordinate range) and mesh resolution (radial and axial number); input the wave energy deposition distribution parameters, including the temperature and density radial profile of the wave heating point obtained from experimental diagnosis or the energy deposition profile given by the wave simulation program. Next, click the parameter parsing and calculation module to process the corresponding parameters, adjust the format of the device geometry file, and give the coordinates of each edge vertex according to the SOLPS requirement format (closed geometry), and save it as a file with the suffix .ogr; calculate the coil cross-sectional current density according to the coil parameters, and then obtain the magnetic flux distribution, as well as the radial and axial magnetic field strengths by calculating the Grad-Shafranov equation. Finally, generate a quadrilateral mesh according to the mesh coordinate range and resolution settings in step 1), and extract the radial coordinates (R) and axial coordinates (Z) of the mesh. Calculate the mesh volume dV=2πRdRdZ according to the axisymmetric principle; save them as a fluid mesh file (suffix .ASCII) and a volume matrix text file (suffix .txt) respectively. Finally, calculate the energy deposition distribution file according to the wave energy deposition distribution parameters. For the radial electron density and temperature profile corresponding to the spiral wave / ion cyclotron heating in the experiment, obtain the distribution information, such as the distribution center coordinates and distribution function, by fitting the experimental data. Assuming the distribution is Gaussian, give the initial source radial and axial distributions:

[0061]

[0062]

[0063]

[0064]

[0065] Among them, S R,helicon S Z,helicon Power density distributions are divided into radial and axial helical waves, S R,ICRH S Z,ICRH The power density distribution of ion cyclotron heating is divided into radial and axial distributions, where R and Z are the radial and axial coordinates of a quadrilateral grid. , The coordinates of the center position of the power density distribution of the radial and axial spiral waves are divided into radial and axial spiral wave power density distributions. , The coordinates of the center position of the ion cyclotron heating power density distribution are divided into radial and axial. , The power density distribution width parameters are divided into radial and axial spiral waves. , The power density distribution width parameter is divided into radial and axial ion cyclotron heating.

[0066] Depending on the experimental conditions, a single-peak Gaussian distribution or Gaussian linear superposition of radial and axial distributions can be selected. Then, the corresponding radial and axial distributions are multiplied and multiplied by the grid volume dV to obtain the initial two-dimensional distribution of the source volume density within the grid. This is then multiplied by the total power or particle flux read to obtain the actual two-dimensional volume density distribution. Next, the two-dimensional volume density distributions of the helical wave and the ion cyclotron-heated source are added together according to electron power, ion work, and particle source classification. The radial and axial one-dimensional source volume density distributions are extracted according to the row and column of the maximum R-coordinate. Finally, the axial one-dimensional distribution is normalized according to SOLPS format requirements, mapping the axial coordinates to the axial grid index ix or the normalized connection length, and exported and saved as the SOLPS external source input file b2.sources.profile. When the wave energy deposition distribution is obtained through other wave propagation simulation programs (such as COMSOL), it is generated and saved as b2.sources.profile following the same steps (axial normalization).

[0067] Furthermore, such as Figure 4 The diagram shows the data processing and visualization module, which is suitable for data processing after SOLPS calculations. The specific steps are as follows: After SOLPS calculations are complete, click the raw data import module, select the initial data file to be read (quadrilateral mesh data files b2fstate, b2fplasmaf, etc., triangular mesh data files fort.44, fort.46, etc., and time-evolving data files b2tallies.nc, etc.), and the corresponding reading script (MATLAB scripts such as read_b2fstate, read_b2fplasma, etc.). Click the data parsing and processing module to start parsing the dimensions of the data and calculating the required parameters. Then, select the plotting parameters and graph style and start plotting. Finally, store the data through the data saving module.

[0068] In summary, this invention provides a SOLPS simulation method suitable for variable specific impulse magneto-plasma electric propulsion devices. The system implementation uses MATLAB software as a platform, utilizing its graphical user interface (GUI) to design an interactive interface and implement the two main steps of SOLPS input file preparation and data processing and visualization in the method flow. This invention not only provides a new simulation method for the transport process analysis of variable specific impulse magneto-plasma electric propulsion devices, but also significantly reduces the complexity of SOLPS simulation of linear plasma devices through the integration of the simulation flow, thereby improving the efficiency of simulation calculations.

[0069] This invention acquires all simulation parameters in a standardized and centralized manner, establishing a unified input interface. This avoids errors caused by inconsistent parameter sources or inconsistent formats in subsequent processes, providing an accurate and consistent data foundation for the entire simulation and ensuring computational reliability from the outset. File generation is automated through an external program, generating all the key input files required by SOLPS. This solves the fundamental problem that most versions of SOLPS cannot generate suitable meshes and geometry files for linear devices, overcoming the technical bottleneck of this general-purpose program in the specific field of VASIMR. By encapsulating complex manual file preparation and specialized magnetic field calculations (such as solving the Grad-Shafranov equations) within an automated process, manual intervention is greatly reduced, improving efficiency and lowering the risk of simulation failure due to operational errors. The SOLPS calculations leverage the maturity and authority of the SOLPS program in simulating complex plasma transport processes, ensuring the physical reliability of the simulation results.

[0070] By importing the meshes and source files generated in the previous steps and specifically tailored for linear devices, SOLPS, a program originally designed for toroidal devices, can be "transformed" for accurately simulating the physical processes of linear electric propulsion devices, thus expanding the value of a mature tool in a new field. In post-processing, the raw data output by SOLPS is automatically transformed into intuitive graphics and analyzable data. This enables rapid visualization of the calculation results, allowing researchers to quickly understand the simulation results, gain insights into physical laws, and greatly improve the efficiency of data analysis. Scripted and standardized post-processing ensures consistency in plotting style and data interpretation, facilitating comparison and research between different schemes.

[0071] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A SOLPS simulation method suitable for variable specific impulse magneto-plasma electric propulsion devices, characterized in that, Includes the following steps: Parameter acquisition: Obtain the simulated parameters of the electric propulsion device; File generation: Based on the simulation parameters, an external program generates the input files required for SOLPS simulation, including device geometry files, fluid mesh files, power source files, and particle source files. SOLPS calculation involves importing the input file into the SOLPS program, which then generates a computational grid and performs plasma simulation calculations. Post-processing involves exporting the SOLPS calculation output data to external programs for data parsing and visualization. In the file generation process, the specific steps for generating the device geometry file and fluid mesh file include: establishing a reference coordinate system based on the axisymmetric characteristics of the linear electric propulsion device, generating a SOLPS-readable device geometry file, calculating the magnetic flux distribution based on the coil parameters, and generating a quadrilateral mesh for SOLPS fluid calculations based on this. The specific process for generating the quadrilateral mesh includes: Read the coil turns, current and coordinate information, and calculate the current density across the coil cross section; The magnetic flux distribution, as well as the radial and axial magnetic field strengths, were obtained by calculating the Grad-Shafranov equations. Generate a quadrilateral mesh based on the mesh setting parameters, and extract the radial coordinate R and axial coordinate Z of the mesh; The mesh volume is calculated using the principle of axisymmetry: dV = 2πR·dR·dZ, where dR and dZ are the radial and axial widths of the mesh element, respectively. The specific process for generating the power source file and particle source file in the file generation includes: generating the radial and axial distributions of the power source and particle source based on wave energy deposition distribution parameters and fluid mesh, and exporting and saving them as SOLPS input format files.

2. The SOLPS simulation method for a variable specific impulse magneto-plasma electric propulsion device according to claim 1, characterized in that, The simulation parameters include device parameters, grid setting parameters, and wave energy deposition distribution parameters.

3. The SOLPS simulation method for a variable specific impulse magneto-plasma electric propulsion device according to claim 2, characterized in that, The device parameters include the device's geometric dimensions, coil dimensions, and current. The grid setting parameters include the grid radial coordinate range, axial coordinate range, and resolution; The wave energy deposition distribution parameters include total electron heating power, total ion heating power, total particle flux, and distribution function.

4. The SOLPS simulation method for a variable specific impulse magneto-plasma electric propulsion device according to claim 3, characterized in that, The wave energy deposition distribution parameters are obtained by fitting the radial electron density and temperature profiles corresponding to spiral wave heating or ion cyclotron heating in the experiment, or by obtaining the calculation results of a multiphysics field coupling simulation platform.

5. The SOLPS simulation method for a variable specific impulse magneto-plasma electric propulsion device according to claim 1, characterized in that, The specific process for generating the power source and particle source files includes: a. By analyzing the radial electron density and temperature profiles corresponding to helical wave heating or ion cyclotron heating in the experiment, the distribution information is obtained, and the source distribution is represented by a Gaussian distribution function: ， ， ， , of which S R,helicon S Z,helicon Power density distributions are divided into radial and axial helical waves, S R,ICRH S Z,ICRH The power density distribution of ion cyclotron heating is divided into radial and axial distributions, where R and Z are the radial and axial coordinates of a quadrilateral grid. , The coordinates of the center position of the power density distribution of the radial and axial spiral waves are divided into radial and axial spiral waves. , The coordinates of the center position of the ion cyclotron heating power density distribution are divided into radial and axial. , The power density distribution width parameters are divided into radial and axial spiral waves. , The power density distribution width parameter is divided into radial and axial ion cyclotron heating. b. Select a unimodal Gaussian distribution or perform Gaussian linear superposition on the radial and axial sides respectively, then multiply the corresponding radial and axial distribution functions together and multiply by the grid volume dV to obtain the two-dimensional distribution of the initial source volume density; c. Multiply the initial two-dimensional source volume density distribution by the total power or particle flux to obtain the actual two-dimensional volume density distribution; d. Based on the classification of electronic power, ion power, and particle source, the two-dimensional source volume density distributions of helical wave heating and ion cyclotron heating are added together, and the one-dimensional source volume density distributions of radial and axial directions are extracted. e. Normalize the axial one-dimensional distribution, map the axial coordinates to the axial grid index or normalized connection length, and export and save it as the SOLPS external source input file b2.sources.profile; f. When the wave energy deposition distribution is obtained through other wave propagation simulation programs, it is axially normalized according to the steps above to generate b2.sources.profile.

6. The SOLPS simulation method for a variable specific impulse magneto-plasma electric propulsion device according to claim 1, characterized in that, The post-processing steps include: The SOLPS official open-source MATLAB scripts are used to read quadrilateral mesh data files, triangular mesh data files, and data files that evolve over time. The data dimensions are analyzed, and graphs are generated and saved based on quadrilateral and triangular grid coordinates.

Images