Method and device for constructing a model of plasma wakefield distribution

Abstract

The application relates to the technical field of plasma computing, in particular to a method and device for constructing a plasma wake body distribution description model. The method comprises the following steps: dividing a plasma wake of a high-speed target into multiple sub-regions, and calculating the reflectivity of each sub-region by using a finite-difference time-domain method; calculating the RCS average value of the high-speed target under multiple frequency bands, and determining the reflectivity threshold value corresponding to each frequency band based on the RCS average value and the reflectivity of each sub-region; determining the effective length of the plasma wake body tail under the corresponding frequency band based on each reflectivity threshold value, wherein the reflectivity in each effective length is not less than the reflectivity threshold value under the corresponding frequency band; dividing the plasma wake into multiple target regions based on the effective lengths; and performing grid division on the corresponding target region based on the frequency limit value of each frequency band, so as to obtain the plasma wake body distribution description model. The application has reasonable grid division and high electromagnetic calculation efficiency.

Description

Technical Field

[0001] This invention relates to the field of plasma computing technology, and in particular to a method and apparatus for constructing a plasma wake distribution description model. Background Technology

[0002] When a high-speed moving target travels at extremely high speeds within the atmosphere, it experiences intense friction with the surrounding atmosphere, creating a plasma contrail left behind it. Radar observations indicate that, under certain flight conditions, plasma contrails are strong scattering sources in the meter-wave to sub-meter-wave band. Therefore, when analyzing the electromagnetic scattering characteristics of high-speed moving targets, the electromagnetic properties of plasma contrails should be taken into account for auxiliary detection.

[0003] Currently, accurate modeling of plasma wake distribution is fundamental to electromagnetic property calculations; therefore, constructing a plasma wake distribution description model has high application value. The current challenge in modeling electromagnetic scattering from plasma wakes lies in their high degree of inhomogeneity and large physical scale. In related technologies, to meet the accuracy requirements of electromagnetic calculations in broadband electromagnetic scattering characteristic calculations, the plasma wake mesh is often divided using the wavelength corresponding to the highest frequency, and a uniform meshing method is adopted. However, due to the large physical scale of plasma wakes, uniform meshing generates a large amount of mesh data, resulting in high computational resource consumption and low computational efficiency, which cannot meet the needs of engineering applications.

[0004] Therefore, there is an urgent need for a method and apparatus for constructing a plasma wake distribution description model to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a method and apparatus for constructing a plasma wake distribution description model, which features reasonable mesh division and high electromagnetic calculation efficiency.

[0006] In a first aspect, embodiments of the present invention provide a method for constructing a plasma wake distribution description model, comprising:

[0007] The plasma wake of a high-speed target is divided into multiple sub-regions, and the reflectivity of each sub-region is calculated using the finite-difference time-domain method.

[0008] Calculate the mean RCS of the high-speed target in multiple frequency bands, and determine the reflectivity threshold corresponding to each frequency band based on the mean RCS and the reflectivity of each sub-region;

[0009] The effective length of the plasma sub-body wake in the corresponding frequency band is determined based on each reflectivity threshold.

[0010] The plasma wake is divided into multiple target regions based on each effective length;

[0011] Based on the frequency limits of each frequency band, the corresponding target area is divided into grids to obtain a plasma wake distribution description model.

[0012] Secondly, embodiments of the present invention also provide an apparatus for constructing a plasma wake distribution description model, comprising:

[0013] The first calculation module is used to divide the plasma wake of a high-speed target into multiple sub-regions and calculate the reflectivity of each sub-region using the finite-difference time-domain method.

[0014] The second calculation module is used to calculate the average RCS of the high-speed target in multiple frequency bands, and determine the reflectivity threshold corresponding to each frequency band based on the average RCS and the reflectivity of each sub-region.

[0015] The determination module is used to determine the effective length of the plasma sub-body wake in the corresponding frequency band based on each reflectivity threshold;

[0016] The first division module is used to divide the plasma wake into multiple target regions based on each effective length;

[0017] The second partitioning module is used to partition the corresponding target area into grids based on the frequency limits of each frequency band, thereby obtaining a plasma wake distribution description model.

[0018] Thirdly, embodiments of the present invention also provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the method described in any embodiment of this specification.

[0019] Fourthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the methods described in any embodiment of this specification.

[0020] This invention provides a method and apparatus for constructing a plasma wake distribution description model. By dividing the plasma wake of a high-speed target into sub-regions, the reflectivity of each sub-region can be accurately obtained. By calculating the average RCS of the high-speed target across multiple frequency bands and combining it with the reflectivity of each sub-region, the reflectivity threshold corresponding to each frequency band can be determined. Based on the reflectivity threshold within any frequency band, if the reflectivity of a sub-region is not less than the threshold, it is considered an effective region, and its corresponding length is considered an effective length; otherwise, it is considered an ineffective length, and its electromagnetic properties are ignored in relation to target identification. Finally, each effective length is divided into multiple target regions, and different regions are meshed based on different frequency limits, making the mesh division of each target region more reasonable and improving electromagnetic computation efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the 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 based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a method for constructing a plasma wake distribution description model according to an embodiment of the present invention;

[0023] Figure 2 This is a hardware architecture diagram of an electronic device provided in an embodiment of the present invention;

[0024] Figure 3 This is a structural diagram of a device for constructing a plasma wake distribution description model according to an embodiment of the present invention;

[0025] Figure 4 This is an electron density distribution map of a high-speed target provided in an embodiment of the present invention;

[0026] Figure 5 A one-dimensional Yee cell diagram;

[0027] Figure 6 The curves show the variation of reflectivity at various locations within the frequency range of 0 to 2 GHz for plasma wake lengths ranging from 2 m to 12 m.

[0028] Figure 7 The curves show the variation of reflectivity at various locations within the frequency range of 0 to 400 MHz for plasma wake lengths ranging from 6 m to 16 m.

[0029] Figure 8The curves show the variation of reflectivity at various locations within the frequency range of 0 to 100 MHz for plasma wake lengths ranging from 36 m to 46 m. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] Please refer to Figure 1 This invention provides a method for constructing a plasma wake distribution description model, the method comprising:

[0032] Step 100: Divide the plasma wake of the high-speed target into multiple sub-regions and calculate the reflectivity of each sub-region using the finite-difference time-domain method.

[0033] Step 102: Calculate the average RCS of the high-speed target in multiple frequency bands, and determine the reflectivity threshold corresponding to each frequency band based on the average RCS and the reflectivity of each sub-region.

[0034] Step 104: Determine the effective length of the plasma sub-body wake in the corresponding frequency band based on each reflectivity threshold, and the reflectivity within each effective length shall not be less than the reflectivity threshold in the corresponding frequency band.

[0035] Step 106: Divide the plasma wake into multiple target regions based on each effective length;

[0036] Step 108: Based on the frequency limits of each frequency band, the corresponding target area is divided into grids to obtain the plasma wake distribution description model.

[0037] This embodiment provides a method for constructing a plasma wake distribution description model. By dividing the plasma wake of a high-speed target into sub-regions, the reflectivity of each sub-region can be accurately obtained. By calculating the average RCS of the high-speed target across multiple frequency bands and combining it with the reflectivity of each sub-region, the reflectivity threshold corresponding to each frequency band can be determined. Based on the reflectivity threshold within any frequency band, if the reflectivity of a sub-region is not less than the threshold, it is considered a valid region, and its corresponding length is considered an effective length; otherwise, it is considered an invalid length, and its electromagnetic properties are ignored in relation to target identification. Finally, each effective length is divided into multiple target regions, and different regions are meshed based on different frequency limits, making the mesh division of each target region more reasonable and improving electromagnetic computation efficiency.

[0038] The following description Figure 1 The execution method for each step is shown.

[0039] First, regarding step 100, the high-speed target can be a glider with a flight altitude of 30 km and a flight speed of 7000 m / s. When this glider moves at extremely high speeds within the atmosphere, it experiences intense friction with the surrounding atmosphere, creating a plasma contrail left behind the glider, such as... Figure 4 As shown. Currently, electromagnetic calculations for plasma wakes typically extend to 300 meters and use uniform mesh partitioning, resulting in a very large computational load that cannot meet the needs of engineering applications.

[0040] In this step, the plasma wake of the high-speed target is divided into multiple sub-regions. The division method is to uniformly divide the plasma wake along the X direction. For example, the division standard is that the interval between adjacent sub-regions in the X direction is 2 meters. The 0 point of X is the starting point of the plasma wake. Along the direction away from the starting point, X increases step by step.

[0041] In some implementations, the specific process of calculating the reflectivity of each sub-region using the finite-difference time-domain method is as follows:

[0042] For unmagnetized plasma, Maxwell's equations and constitutive equations are as follows:

[0043]

[0044]

[0045] D=ε0εE (3)

[0046] J=σE (4)

[0047] In the formula, E is the electric field strength, D is the electric flux density, H is the magnetic field strength, J is the current density, ε0 ​​is the permittivity in vacuum, μ0 is the permeability in vacuum, ε is the relative permittivity of the medium, and σ is the conductivity.

[0048] For a one-dimensional TEM (Transverse Electric and Magnetic Field) wave, the vectors in Cartesian coordinates are represented as follows:

[0049]

[0050] Under the above coordinate system, equations (1) and (2) can be written in the following form:

[0051]

[0052]

[0053] In the formula, E x and E y Let E and H be the electric field intensities along the x-axis and y-axis, respectively, located at the same point. x and H y Let H represent the magnetic field strength along the x-axis and y-axis, respectively, and let J be the magnetic field strength located at the same point. x and J y Let J represent the current density along the x-axis and y-axis, respectively, and let J be the denoting number of the points where they lie. and These are the directional components of the electromagnetic wave along the x-axis and y-axis in Cartesian coordinates, respectively.

[0054] For one-dimensional problems, E, H, and J can be calculated as follows: Figure 5 The one-dimensional Yee cell diagram shown is discretized.

[0055] By discretizing the space and time using equations (3), (6), and (7), we can obtain the following formula:

[0056]

[0057]

[0058]

[0059] In the formula, n represents the time step, k represents the cell position, Δt is the discrete time, Δz is the discrete distance, ν is the plasma collision frequency, and ω is the plasma collision frequency. p This is the plasma resonant frequency.

[0060] Based on the iterative formulas (8), (9), and (10), the electric and magnetic fields in the one-dimensional plasma can be obtained. Substituting the electric field result into the reflectivity calculation formula (11), the reflectivity of the plasma in each sub-region can be calculated. The formula for calculating the reflectivity is:

[0061]

[0062] In the formula, Re is the reflectivity of the plasma wake; E i For the incident electromagnetic wave field strength, E s To reflect electromagnetic wave field strength.

[0063] Then, the specific execution process for step 102 includes:

[0064] For each sub-region, the following steps are performed: the RCS value is determined based on the reflectivity of the plasma wake in that sub-region, and the first difference between the RCS value of the plasma wake in that sub-region and the reflectivity of that sub-region is determined based on the calculation formulas for reflectivity and RCS value; the first RCS value is determined based on the degree of influence of the RCS value of the plasma wake on the average RCS value of the corresponding high-speed target.

[0065] For each frequency band, the difference between the average RCS value of the high-speed target in that frequency band and the first difference and the first RCS value is used as the reflectivity threshold of that frequency band.

[0066] In this embodiment, when the incident electromagnetic wave field strength is unit field strength, the formula for calculating the reflectivity of the plasma wake in each sub-region is:

[0067]

[0068] The RCS value of the plasma wake in each sub-region is:

[0069]

[0070] The formula for calculating the first difference is: Δσ1=σ wi -Re i =11 (dB);

[0071] The formula for calculating the reflectivity threshold of any frequency band is: Re maxj =σ t -Δσ1-Δσ2;

[0072] In the formula, Re i E represents the reflectivity of the plasma wake in the i-th sub-region, where i = 1, 2, ..., n, and n is the number of sub-regions. s E represents the reflected electromagnetic wave field strength. i σ is the incident electromagnetic field strength; wi Re is the RCS value of the plasma wake in the i-th sub-region; Δσ1 is the first difference; Δσ2 is the first RCS value; Re maxj Let be the reflectivity threshold of the j-th frequency band, where j = 1, 2, ..., m, and m is the number of frequency bands.

[0073] In the above steps, the frequency band selection can be determined based on the actual operating environment of the high-speed target. The smaller the frequency range of each band, the higher the calculation accuracy. For example, the frequency bands can be selected according to the following criteria: the first band is 0–100MHz, the second band is 100–400MHz, the third band is 400MHz–1GHz, the fourth band is 1GHz–2GHz, and the fifth band is greater than 2GHz. Furthermore, the average RCS value of a high-speed target varies depending on its attitude. Here, we take the average RCS value of the high-speed target within the head-up ±45° and pitch ±20° range across different frequency bands.

[0074] Furthermore, when the RCS value of the plasma wake is 10 dB smaller than the average RCS value of the target body, the influence of the plasma wake on the overall RCS of the target can be considered negligible. Therefore, the first RCS value is preferably 10 dB. At this time, Re maxj =σ t -twenty one.

[0075] Then, regarding step 104, determining the effective length of the plasma sub-body wake in the corresponding frequency band based on each reflectivity threshold includes:

[0076] For each frequency band, each sub-region is traversed sequentially along the direction away from the high-speed target. For each traversed sub-region, the following is performed:

[0077] S1, determine whether there is at least one reflectivity greater than the reflectivity threshold corresponding to the frequency band in the current sub-region. If yes, execute S2; otherwise, execute S3.

[0078] S2, take the next sub-region as the current sub-region, and return to execute S1;

[0079] S3, determine the length of the wake corresponding to the previous sub-region as the effective length of the plasma wake in this frequency band.

[0080] In this step, only regions with reflectivity greater than the reflection threshold are considered for their electromagnetic properties; otherwise, their influence on electromagnetic properties is ignored, and no calculation is performed on that sub-region or the sub-regions that follow it.

[0081] Then, regarding step 106, dividing the plasma wake into multiple target regions based on each effective length includes:

[0082] The effective lengths are sorted in ascending order, and the region between adjacent effective lengths is taken as a target region; for the smallest effective length, the region between zero and the smallest effective length is taken as the target region.

[0083] Dividing the target region in this way can make the plasma wakes in each target region have similar electromagnetic scattering characteristics, which is beneficial for subsequent grid division of each region.

[0084] Finally, regarding step 108, the grid division of the corresponding target area based on the frequency limits of each frequency band includes:

[0085] Along the direction away from the high-speed target, the target regions other than the last target region are each divided into wavelengths corresponding to the lower limit frequency of the frequency band corresponding to the target region.

[0086] For the last target region, the wavelength corresponding to the upper limit frequency of the frequency band corresponding to the target region is divided into segments.

[0087] In this step, the mesh is generated according to the wavelength corresponding to the lower limit frequency of the frequency band corresponding to the target region. This reduces the number of meshes and improves computational efficiency while maintaining meshing accuracy. For the last target region, since the lower frequency limit is 0, it is divided according to the upper limit. Of course, users can also divide it according to the wavelength corresponding to the average frequency of the frequency band; this application does not impose specific limitations.

[0088] To illustrate the beneficial effects of this solution, the following will use... Figure 3 The glider shown is the target, and the grid is divided using the method provided in this invention.

[0089] It should be noted that: Figure 3 The glider shown is in an attitude range of ±45° head-up and ±20° pitch, at a flight altitude of 30 km and a flight speed of 7000 m / s. Its electron density diagram is as follows. Figure 5 As shown, the wake thickness is 5 meters. It should be noted that the calculation method for the electron density map of any high-speed target is existing technology, and this application does not limit its calculation process.

[0090] First, such as Figures 6-8 As shown, the X-interval of each sub-region is 2 meters. When calculating the reflectivity at any X point of the plasma wake using the finite-difference time-domain method, the plasma parameter is taken as the maximum electron density at X, resulting in... Figures 6-8 The reflectance variation curve is shown.

[0091] Then, according to the above frequency band division standards and calculation methods, Figure 4 The mean head-facing RCS and reflectivity threshold of the glider shown were calculated, and the results are shown in Table 1.

[0092] Table 1. Mean RCS and reflectivity threshold of the target body in the head-facing direction.

[0093]

[0094] As shown in Table 1, with 100MHz, 400MHz, and 1GHz as boundaries, the reflectivity threshold is -22dB for frequencies less than 100MHz, -30dB for frequencies between 100MHz and 400MHz, -32dB for frequencies between 400MHz and 1GHz, and -40dB for frequencies between 1GHz and 2GHz.

[0095] Combining Table 1 and Figure 6 It can be seen that when the frequency domain is greater than 2 GHz, the influence of the plasma wake on the target's RCS can be ignored. For frequencies between 1 GHz and 2 GHz, the plasma wake only needs to be calculated to a length of 4 m, i.e., the effective length is 4 m; for frequencies between 400 MHz and 1 GHz, the plasma wake needs to be calculated to a length of 6 m, i.e., the effective length is 6 m. For example... Figure 7 As shown, with frequencies between 100MHz and 400MHz, the plasma wake needs to be calculated to a depth of 10m, meaning the effective length is 10m. For example... Figure 8 As shown, for frequencies less than 100MHz, the plasma wake needs to be calculated to 46m, i.e., the effective length is 46m.

[0096] After determining the effective length of each frequency band, the plasma wake can be divided into multiple target regions. Along the direction away from the high-speed target, the target regions are 0–4 meters, 4–6 meters, 6–10 meters, and 10–46 meters. Within the 0–4 meter range, the electromagnetic characteristics are strong, so this region is divided using a wavelength corresponding to 2 GHz; within the 4–6 meter range, it is divided using a wavelength corresponding to 1 GHz; within the 6–10 meter range, it is divided using a wavelength corresponding to 400 MHz; and within the 10–46 meter range, the electromagnetic characteristics are weaker, so it is divided using a wavelength corresponding to 100 MHz. In this way, each target region is divided according to its electromagnetic strength using different grid densities, reducing computational complexity while maintaining computational accuracy.

[0097] The above method is used to construct a volume distribution description model of the plasma wake. When detecting the entire plasma wake at 2 GHz, since the electromagnetic characteristics of the wake are mainly concentrated in the 0–4 meter range, it is sufficient to ensure high computational accuracy in this region. In other regions, the mesh is slightly sparse, and some electromagnetic waves will pass through the middle of the mesh, but this has little impact on the overall computational accuracy. When detecting the entire plasma wake at 300 MHz, the effective length is 10 meters. In the 6–10 meter range, the mesh is divided according to the effective detection of the wake, so there is a good detection effect in the 6–10 meter range. In the 0–6 meter range, the mesh is divided in a denser manner, resulting in even better detection. In the 10–46 meter range, the electromagnetic characteristics are very weak, so the sparse mesh does not affect the detection accuracy.

[0098] In summary, using regional grid division can ensure detection accuracy while improving computational efficiency.

[0099] like Figure 2 , Figure 3 As shown, this embodiment of the invention provides a device for constructing a plasma wake distribution description model. The device embodiment can be implemented through software, hardware, or a combination of both. From a hardware perspective, as... Figure 2 The diagram shown is a hardware architecture diagram of an electronic device containing a plasma wake distribution description model construction device provided in an embodiment of the present invention, except for... Figure 2 In addition to the processor, memory, network interface, and non-volatile memory shown, the electronic device in the embodiment may also include other hardware, such as a forwarding chip responsible for processing packets. Taking software implementation as an example, such as... Figure 3 As shown, a device in a logical sense is formed by the CPU of the electronic device in which it is located reading the corresponding computer program from the non-volatile memory into the memory for execution.

[0100] This embodiment provides a device for constructing a plasma wake distribution description model, comprising:

[0101] The first calculation module 300 is used to divide the plasma wake of a high-speed target into multiple sub-regions and calculate the reflectivity of each sub-region using the finite-difference time-domain method.

[0102] The second calculation module 302 is used to calculate the average RCS of the high-speed target in multiple frequency bands, and determine the reflectivity threshold corresponding to each frequency band based on the average RCS and the reflectivity of each sub-region.

[0103] The determining module 304 is used to determine the effective length of the plasma sub-body wake in the corresponding frequency band based on each reflectance threshold, wherein the reflectance within each effective length is not less than the reflectance threshold in the corresponding frequency band.

[0104] The first division module 306 is used to divide the plasma wake into multiple target regions based on each effective length;

[0105] The second partitioning module 308 is used to partition the corresponding target area into grids based on the frequency limits of each frequency band, thereby obtaining a plasma wake distribution description model.

[0106] In some implementations, the second calculation module 302 is used to perform the following operations:

[0107] For each sub-region, the following steps are performed: the RCS value is determined based on the reflectivity of the plasma wake in that sub-region, and the first difference between the RCS value of the plasma wake in that sub-region and the reflectivity of that sub-region is determined based on the calculation formulas for reflectivity and RCS value; the first RCS value is determined based on the degree of influence of the RCS value of the plasma wake on the average RCS value of the corresponding high-speed target.

[0108] For each frequency band, the difference between the average RCS value of the high-speed target in that frequency band and the first difference and the first RCS value is used as the reflectivity threshold of that frequency band.

[0109] In some implementations, for each sub-region:

[0110] When the incident electromagnetic field strength is unit, the formula for calculating the reflectivity of the plasma wake in each sub-region is:

[0111]

[0112] The RCS value of the plasma wake in each sub-region is:

[0113]

[0114] The formula for calculating the first difference is: Δσ1=σ wi -Re i ;

[0115] The formula for calculating the reflectivity threshold of any frequency band is: Re maxj =σ t -Δσ1-Δσ2;

[0116] In the formula, Re i E represents the reflectivity of the plasma wake in the i-th sub-region, where i = 1, 2, ..., n, and n is the number of sub-regions. s E represents the reflected electromagnetic wave field strength. i σ is the incident electromagnetic field strength; wi Re is the RCS value of the plasma wake in the i-th sub-region; Δσ1 is the first difference; Δσ2 is the first RCS value; Re maxj Let be the reflectivity threshold of the j-th frequency band, j = 1, 2, ..., m, where m is the number of frequency bands, and the first RCS value is 10 dB.

[0117] In some implementations, the determining module 304 is used to perform the following operations:

[0118] For each frequency band, each sub-region is traversed sequentially along the direction away from the high-speed target. For each traversed sub-region, the following is performed:

[0119] S1, determine whether there is at least one reflectivity greater than the reflectivity threshold corresponding to the frequency band in the current sub-region. If yes, execute S2; otherwise, execute S3.

[0120] S2, take the next sub-region as the current sub-region, and return to execute S1;

[0121] S3, determine the length of the wake corresponding to the previous sub-region as the effective length of the plasma wake in this frequency band.

[0122] In some implementations, the first partitioning module 306 is used to perform the following operations:

[0123] The effective lengths are sorted in ascending order, and the region between adjacent effective lengths is taken as a target region; for the smallest effective length, the region between zero and the smallest effective length is taken as the target region.

[0124] In some implementations, the second partitioning module 308 is used to perform the following operations:

[0125] Along the direction away from the high-speed target, the target regions other than the last target region are each divided into wavelengths corresponding to the lower limit frequency of the frequency band corresponding to the target region.

[0126] For the last target region, the wavelength corresponding to the upper limit frequency of the frequency band corresponding to the target region is divided into segments.

[0127] It is understood that the structures illustrated in the embodiments of the present invention do not constitute a specific limitation on the apparatus for constructing a plasma contrail distribution description model. In other embodiments of the present invention, an apparatus for constructing a plasma contrail distribution description model may include more or fewer components than illustrated, or combine some components, or split some components, or arrange different components. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0128] The information interaction and execution process between the modules in the above-mentioned device are based on the same concept as the method embodiment of the present invention, and the specific details can be found in the description of the method embodiment of the present invention, and will not be repeated here.

[0129] This invention also provides an electronic device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements a method for constructing a plasma wake distribution description model according to any embodiment of this invention.

[0130] This invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform a method for constructing a plasma wake distribution description model according to any embodiment of this invention.

[0131] Specifically, a system or apparatus equipped with a storage medium may be provided, on which software program code implementing the functions of any of the embodiments described above is stored, and the computer (or CPU or MPU) of the system or apparatus may read and execute the program code stored in the storage medium.

[0132] In this case, the program code read from the storage medium can itself implement the function of any of the above embodiments, and therefore the program code and the storage medium storing the program code constitute part of the present invention.

[0133] Examples of storage media used to provide program code include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, program code can be downloaded from a server computer via a communication network.

[0134] Furthermore, it should be clear that not only can the program code read by the computer be executed, but also the operating system or other components operating on the computer can be instructed based on the program code to perform some or all of the actual operations, thereby realizing the function of any of the embodiments described above.

[0135] Furthermore, it is understood that the program code read from the storage medium is written to the memory set in the expansion board inserted into the computer or to the memory set in the expansion module connected to the computer. Then, based on the instructions of the program code, the CPU or other components installed on the expansion board or expansion module execute some and all of the actual operations, thereby realizing the function of any of the above embodiments.

[0136] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications 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.

Claims

1. A method for constructing a plasma wake distribution description model, characterized in that, include: The plasma wake of a high-speed target is divided into multiple sub-regions, and the reflectivity of each sub-region is calculated using the finite-difference time-domain method. Calculate the mean RCS of the high-speed target in multiple frequency bands, and determine the reflectivity threshold corresponding to each frequency band based on the mean RCS and the reflectivity of each sub-region; The effective length of the plasma wake in the corresponding frequency band is determined based on each reflectivity threshold, and the reflectivity within each effective length is not less than the reflectivity threshold in the corresponding frequency band. The plasma wake is divided into multiple target regions based on each effective length; Based on the frequency limits of each frequency band, the corresponding target area is divided into grids to obtain a plasma wake distribution description model. The determination of the reflectivity threshold for each frequency band based on the mean RCS and the reflectivity of each sub-region includes: For each sub-region, the following steps are performed: the RCS value is determined based on the reflectivity of the plasma wake in that sub-region, and the first difference between the RCS value of the plasma wake in that sub-region and the reflectivity of that sub-region is determined based on the calculation formulas for reflectivity and RCS value; the first RCS value is determined based on the degree of influence of the RCS value of the plasma wake on the average RCS value of the corresponding high-speed target. For each frequency band, the difference between the average RCS value of the high-speed target in that frequency band and the first difference and the first RCS value is used as the reflectivity threshold of that frequency band.

2. The method according to claim 1, characterized in that, For each sub-region: When the incident electromagnetic field strength is unit, the formula for calculating the reflectivity of the plasma wake in each sub-region is: ； The RCS value of the plasma wake in each sub-region is: The formula for calculating the first difference is: ; The formula for calculating the reflectivity threshold of any frequency band is: ; In the formula, Let be the reflectivity of the plasma wake in the i-th sub-region, i = 1, 2, ..., n, where n is the number of sub-regions; To reflect electromagnetic wave field strength; The intensity of the incident electromagnetic field; Let RCS be the value of the plasma wake in the i-th sub-region; This is the first difference; This is the first RCS value; Let be the reflectivity threshold of the j-th frequency band, where j = 1, 2, ..., m, and m is the number of frequency bands.

3. The method according to claim 2, characterized in that, The first RCS value is 10dB.

4. The method according to claim 1, characterized in that, The determination of the effective length of the plasma wake in the corresponding frequency band based on each reflectivity threshold includes: For each frequency band, each sub-region is traversed sequentially along the direction away from the high-speed target. For each traversed sub-region, the following is performed: S1, determine whether there is at least one reflectivity greater than the reflectivity threshold corresponding to the frequency band in the current sub-region. If yes, execute S2; otherwise, execute S3. S2, take the next sub-region as the current sub-region, and return to execute S1; S3, determine the length of the wake corresponding to the previous sub-region as the effective length of the plasma wake in this frequency band.

5. The method according to claim 1, characterized in that, The process of dividing the plasma wake into multiple target regions based on each effective length includes: The effective lengths are sorted in ascending order, and the region between adjacent effective lengths is taken as a target region; for the smallest effective length, the region between zero and the smallest effective length is taken as the target region.

6. The method according to claim 1, characterized in that, The method of dividing the corresponding target area into grids based on the frequency limits of each frequency band includes: Along the direction away from the high-speed target, the target regions other than the last target region are each divided into wavelengths corresponding to the lower limit frequency of the frequency band corresponding to the target region. For the last target region, the wavelength corresponding to the upper limit frequency of the frequency band corresponding to the target region is divided into segments.

7. A device for constructing a plasma wake distribution description model, characterized in that, include: The first calculation module is used to divide the plasma wake of a high-speed target into multiple sub-regions and calculate the reflectivity of each sub-region using the finite-difference time-domain method. The second calculation module is used to calculate the average RCS of the high-speed target in multiple frequency bands, and determine the reflectivity threshold corresponding to each frequency band based on the average RCS and the reflectivity of each sub-region. The determination module is used to determine the effective length of the plasma wake in the corresponding frequency band based on each reflectivity threshold, wherein the reflectivity within each effective length is not less than the reflectivity threshold in the corresponding frequency band; The first division module is used to divide the plasma wake into multiple target regions based on each effective length; The second partitioning module is used to divide the corresponding target area into grids based on the frequency limits of each frequency band, so as to obtain a plasma wake distribution description model. The determination of the reflectivity threshold for each frequency band based on the mean RCS and the reflectivity of each sub-region includes: For each sub-region, the following steps are performed: the RCS value is determined based on the reflectivity of the plasma wake in that sub-region, and the first difference between the RCS value of the plasma wake in that sub-region and the reflectivity of that sub-region is determined based on the calculation formulas for reflectivity and RCS value; the first RCS value is determined based on the degree of influence of the RCS value of the plasma wake on the average RCS value of the corresponding high-speed target. For each frequency band, the difference between the average RCS value of the high-speed target in that frequency band and the first difference and the first RCS value is used as the reflectivity threshold of that frequency band.

8. A computing device comprising a memory and a processor, wherein the memory stores a computer program, and the processor, when executing the computer program, implements the method as described in any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the method of any one of claims 1-6.

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