A modeling method, system, device and medium for high-speed plasma reflecting electromagnetic waves under a large-bandwidth system

Abstract

A modeling method, system, device, and medium for high-speed plasma reflected electromagnetic waves under a large bandwidth regime is disclosed. The method includes: establishing a high-speed plasma layered model, establishing a high-speed plasma layered reflection analysis model under a large bandwidth regime based on the high-speed plasma layered model, and then solving the electromagnetic wave characterization of high-speed plasma reflected electromagnetic waves under a large bandwidth regime based on the high-speed plasma layered reflection analysis model. The system, device, and medium are used to implement a modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth regime. This invention obtains the reflected electromagnetic waves of high-speed plasma by calculating the actual complex reflection coefficients of each layer of plasma in the high-speed plasma layered model. It has the characteristics of being able to reflect the velocity distribution of the coupled flow field of broadband reflected electromagnetic waves and revealing the electromagnetic reflection mechanism of the plasma sheath-encased target under a large bandwidth regime.

Description

Technical Field

[0001] This invention relates to the field of broadband radar target detection technology, specifically to a modeling method, system, device, and medium for high-speed plasma reflected electromagnetic waves under a large bandwidth system. Background Technology

[0002] When a hypersonic vehicle flies in near space, the surrounding gas is ionized due to high temperature and pressure, generating a non-uniform high-speed plasma layer that surrounds the vehicle's surface. This non-uniform high-speed plasma layer is called the plasma sheath. The plasma sheath is composed of various particles, mainly electrons, and absorbs, reflects, and refracts incident electromagnetic waves, causing amplitude and phase distortions in the electromagnetic waves. The electron density distribution and velocity field distribution vary at different locations within the plasma sheath, and the difference in the incident depth of the electromagnetic waves in each region leads to different reflection coefficients, phase shift coefficients, and Doppler frequencies in the reflected electromagnetic waves. This results in a complex modulation effect in the total reflected electromagnetic waves from the target enveloped by the plasma sheath, including amplitude and phase fluctuations, and Doppler spectrum shift / broadening.

[0003] Currently, research on electromagnetic waves reflected from targets encased in plasma sheaths is based on narrowband electromagnetic waves, lacking research on the impact of bandwidth on the modulation of reflected electromagnetic wave signals. Modern high-resolution radars primarily use broadband signals, which have a wide frequency distribution range. The velocity field distribution characteristics within the plasma sheath cause the frequency components of the broadband signal to couple with corresponding flow field velocities at different incident depths, resulting in broadening in the Doppler spectrum. Simultaneously, these factors lead to corresponding modulation spectra in the broadband electromagnetic waves. These phenomena cannot be represented by traditional modeling methods. Therefore, a modeling method for high-speed plasma reflected electromagnetic waves under large bandwidth conditions remains to be developed. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention aims to provide a modeling method, system, device, and medium for high-speed plasma reflected electromagnetic waves under a large bandwidth system. The method performs frequency domain diversity processing on broadband electromagnetic waves, calculates the layered reflection model of the diversity signal in high-speed plasma, and models the reflected electromagnetic waves through vector accumulation. It has the characteristics of being able to reflect the velocity distribution of the coupled flow field of broadband reflected electromagnetic waves and revealing the electromagnetic reflection mechanism of the plasma sheath-encased target under a large bandwidth system.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system includes the following steps:

[0007] Step 1: Establish a high-speed plasma layering model;

[0008] Step 2: Establish a high-speed plasma layered reflection analysis model under a large bandwidth system based on the high-speed plasma layered model;

[0009] Step 3: Solve the electromagnetic wave characterization of high-speed plasma reflection under a large bandwidth system based on the high-speed plasma layered reflection analysis model.

[0010] Step 1 specifically includes:

[0011] Step 1.1: Based on the high-speed plasma thickness l and the thickness d of the nth plasma layer... n and the total thickness from the first plasma layer to the nth plasma layer Solving for the electron density n of the nth layer of a high-speed plasma layer model e,n :

[0012]

[0013] In the formula, n is the sequence number of the high-speed plasma layer model, l peak This represents the distance from the target surface when the peak electron density is reached, where n = 1, 2, 3...N, and N is the total number of layers in the high-speed plasma layering model.

[0014] Step 1.2: Based on the unit charge e and electron mass m e And the vacuum permittivity ε0, based on the high-speed plasma layer stratification model in step 1.1, the electron density n of the nth layer plasma. e,n Solve for the characteristic angular frequency ω of the nth plasma layer. p,n and the characteristic frequency f of the nth plasma layer p,n :

[0015]

[0016]

[0017] Step 2 specifically includes:

[0018] Step 2.1: Based on the starting frequency f of the broadband electromagnetic wave c Given the bandwidth B, find the termination frequency f of the broadband electromagnetic wave. end =f c +B;

[0019] Step 2.2: Based on the broadband electromagnetic wave starting frequency f in Step 2.1 c and broadband electromagnetic wave termination frequency f end The frequency domain range of the broadband electromagnetic wave is obtained, and the starting frequency f of the broadband electromagnetic wave is... c to the broadband electromagnetic wave termination frequency f endWithin this range, frequency domain diversity processing of broadband electromagnetic waves from high-speed plasma is performed:

[0020] When broadband electromagnetic waves are incident on high-speed plasma, the following situations occur:

[0021] Case 2.2.1: When the termination frequency f of the incident broadband electromagnetic wave end The frequency f of the outermost plasma layer of the high-speed plasma is less than that of the outermost plasma layer. p,1 At that time, broadband electromagnetic waves are reflected only in the outermost layer of high-speed plasma;

[0022] Case 2.2.2: When the peak characteristic frequency f of the high-speed plasma p,max Less than the starting frequency f of the incident broadband electromagnetic wave c At that time, broadband electromagnetic waves completely penetrated the high-speed plasma and were reflected on the surface of the spacecraft.

[0023] Case 2.2.3, when f p,1 <f c <f end <f p,max At that time, the broadband electromagnetic wave is incident as a whole into the high-speed plasma, with different frequency components corresponding to different incident depths, based on the diversity signal carrier frequency f. i Equal to plasma characteristic frequency f p,n Create a diversity signal, where i is the carrier frequency sequence number of the diversity signal, i = 0, 1, 2, ..., I, and I represents the total number of diversity signals obtained after broadband electromagnetic wave frequency diversity processing. I f represents the maximum diversity frequency obtained after frequency diversity processing of broadband electromagnetic waves. p,n The characteristic frequency of the nth plasma layer is f, and the carrier frequency of the diversity signal is f. i This corresponds to the characteristic frequencies of each plasma layer within the intersection range of the broadband electromagnetic wave frequency range and the characteristic frequencies of each plasma layer.

[0024] Case 2.2.4, when f c <f p,1 <f end <f pmax At that time, a broadband electromagnetic wave component is incident into the high-speed plasma, with different frequency components corresponding to different incident depths, based on the diversity signal carrier frequency f. i Equal to plasma characteristic frequency f p,n Create diversity signals;

[0025] Case 2.2.5, when f p,1 <f c <f p,max <f endWhen broadband electromagnetic waves are incident on the interior of high-speed plasma, some diversity signals penetrate the high-speed plasma and are transmitted to the target surface, while simultaneously generating transparent transmission and electromagnetic shielding effects.

[0026] Step 2.3: Calculate the complex permittivity ε of each plasma layer. n,i Propagation constant k n,i and intrinsic wave impedance Z n,i Based on the vacuum permittivity ε0 and the collision frequency v of the nth layer plasma p,n Based on the characteristic angular frequency ω of the nth layer plasma p,n and the carrier frequencies f of each diversity signal of the incident electromagnetic wave in step 2.2 i The complex permittivity ε of each plasma layer was obtained. n,i :

[0027]

[0028] Where j is the imaginary unit.

[0029] The complex permittivity ε of the nth layer plasma n,i The carrier frequencies f of the combined incident electromagnetic wave diversity signals i Given the vacuum permeability μ0, solve for the propagation constant k of the nth plasma layer. n,i The intrinsic wave impedance Z of the nth layer plasma n,i :

[0030]

[0031]

[0032] Step 2.4: The propagation constant k of the nth layer plasma calculated in Step 2.3. n,i The intrinsic wave impedance Z of the nth layer plasma n,i Combine the vacuum permeability μ0 and the thickness d of the nth plasma layer n The transport matrix of the nth layer plasma can be calculated using the hyperbolic sine function sinh and the hyperbolic cosine function cosh.

[0033]

[0034] Step 2.5: Based on the intrinsic wave impedance Z0 of the incident medium and the intrinsic wave impedance Z of the outermost plasma. 1,i The outermost plasma reflectance R is obtained from the plasma reflectance calculation formula. 1,i Based on the plasma transport matrices of each layer in step 2.4, calculate the reflection coefficient R between adjacent plasmas. n,i ':

[0035]

[0036] Step 2.6: Based on the plasma transport matrices of each layer in Step 2.4, calculate the single-layer transmission coefficient T of the nth plasma layer. u,i :

[0037]

[0038] Where u is the layer number of the high-speed plasma layer model;

[0039] Step 2.7: Calculate the high-speed plasma layered complex reflection coefficient: Combine the reflection coefficients R of each adjacent plasma in Step 2.5. n,i 'and the monolayer plasma transmission coefficient T in step 2.6 u,i Multiply the complex reflection coefficient of the nth plasma layer by the single-layer transmission coefficient of each plasma layer in the incident and exit paths to obtain the diversity signal carrier frequency f. i Complex reflection coefficient reflected from the nth layer of plasma into free space:

[0040]

[0041] Step 2.8: Based on the diversity processing in Step 2.2, each diversity signal is processed at a carrier frequency f. i The method for calculating the reflection coefficient of incident high-speed plasma and the layered reflection coefficients in step 2.7 is used to obtain the reflection coefficients of each plasma layer:

[0042] R all,i =[R 1,i R 2,i R 3,i …R n,i ]

[0043] Among them, R n,i This indicates that the diversity signal is in the form of a carrier frequency f. i The complex reflection coefficient, R, of the nth layer plasma reflected into free space. all,i This indicates that the diversity signal is in the form of a carrier frequency f. i The reflection coefficient matrix of each plasma layer is given, where i is the carrier frequency sequence number of the diversity signal, i = 0, 1, 2, ..., I, and I represents the total number of diversity signals obtained after broadband electromagnetic wave frequency diversity processing.

[0044] Step 3 specifically includes:

[0045] Step 3.1: Calculate the Doppler frequencies of each diversity signal coupling: based on the velocity v of each layer of the high-speed plasma flow field. n Solve for the frequency f of each diversity signal. i The corresponding coupled Doppler frequency f d,i :

[0046]

[0047] Step 3.2: Based on the coupling Doppler frequency f in Step 3.1 d,i Solve for the reflected electromagnetic wave E of the nth layer of high-speed plasma. R (t,n): Suppose that the broadband electromagnetic wave can be divided into I diversity signals. Based on the spatial distribution characteristics of the reflection coefficients of each diversity signal in the high-speed plasma, the broadband electromagnetic wave reflection model of the nth layer of the high-speed plasma is solved by vector accumulation as follows:

[0048]

[0049] Among them, R n,i Let |R| be the reflection coefficient of the i-th diversity signal at the n-th layer. n,i | indicates the magnitude of the reflection coefficient. This represents the phase modulation coefficient of the reflection coefficient on the incident electromagnetic signal;

[0050] Step 3.3: Calculate the electromagnetic wave E reflected by high-speed plasma under a large bandwidth system. R (t): Broadband electromagnetic wave reflection model E based on the nth layer plasma of the high-speed plasma in step 3.2. R The electromagnetic waves reflected by high-speed plasma under a large bandwidth regime (t,n) are shown below:

[0051]

[0052] A modeling system for high-speed plasma reflected electromagnetic waves under a large bandwidth regime includes:

[0053] High-speed plasma parameter model module: Establishes a high-speed plasma stratification model and obtains the high-speed plasma stratified electron density n. e,n Characteristic angular frequency ω p,n Characteristic frequency f p,n ;

[0054] Layered Reflection Coefficient Calculation Module: Based on the high-speed plasma layering model, a high-speed plasma layered reflection analysis model under a large bandwidth system is established to calculate the diversity signal at the carrier frequency f. i The complex reflection coefficient R reflected from the nth layer plasma into free space n,i ;

[0055] High-speed plasma electromagnetic wave reflection module under large bandwidth regime: Based on the hierarchical reflection analysis model of high-speed plasma under large bandwidth regime, the electromagnetic wave reflection characterization of high-speed plasma under large bandwidth regime is solved, and the electromagnetic wave E reflected by high-speed plasma under large bandwidth regime is obtained. R (t).

[0056] A modeling device for high-speed plasma reflected electromagnetic waves under a large bandwidth system includes:

[0057] Memory: Used to store the computer program that implements the modeling method for high-speed plasma reflection electromagnetic waves under a large bandwidth system;

[0058] Processor: Used to implement the modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system when executing the computer program.

[0059] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of a modeling method for high-speed plasma reflected electromagnetic waves under a high bandwidth regime.

[0060] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0061] (1) This invention establishes a high-speed plasma layering model to simulate the actual situation, realizes the feasibility of analyzing high-speed plasma, provides a parameter basis for establishing a high-speed plasma layering reflection analysis model, and has the characteristics of simple method and low modeling difficulty.

[0062] (2) This invention establishes a high-speed plasma layered reflection analysis model and obtains the layered reflection coefficient of high-speed plasma through frequency domain diversity method and improved transmission line method, which has the characteristics of low computational complexity.

[0063] (3) This invention, by solving the characterization of high-speed plasma reflected electromagnetic waves under a large bandwidth system, reflects the velocity distribution of the coupled flow field of broadband reflected electromagnetic waves, reveals the electromagnetic reflection mechanism of the target covered by the plasma sheath under a large bandwidth system, fills the gap in modeling high-speed plasma reflected electromagnetic waves under a large bandwidth system, and has the characteristics of high modeling accuracy.

[0064] In summary, compared with existing technologies, this invention, by establishing a high-speed plasma layering model and a high-speed plasma layering reflection analysis model, and solving the characterization of electromagnetic waves reflected by high-speed plasma under a large bandwidth system, has the characteristics of low modeling difficulty, low computational complexity, and high modeling accuracy, providing a model basis for the analysis of broadband electromagnetic waves reflected by targets covered by plasma sheaths. Attached Figure Description

[0065] Figure 1 This is a flowchart of the method of the present invention.

[0066] Figure 2 This is a schematic diagram of high-speed plasma reflecting electromagnetic waves under a wide bandwidth system. Detailed Implementation

[0067] The present invention will now be described in detail with reference to the accompanying drawings.

[0068] See Figure 1 A modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system includes the following steps:

[0069] Step 1: Establish a high-speed plasma layering model;

[0070] Step 2: Establish a high-speed plasma layered reflection analysis model under a large bandwidth system based on the high-speed plasma layered model;

[0071] Step 3: Solve the electromagnetic wave characterization of high-speed plasma reflection under a large bandwidth system based on the high-speed plasma layered reflection analysis model.

[0072] See Figure 2 After broadband electromagnetic waves are incident on high-speed plasma, the spatial distribution of the reflection coefficient corresponding to the broadband electromagnetic waves exhibits a multi-peak state. Based on the velocity difference of the high-speed plasma flow field in each layer coupled with broadband electromagnetic waves, the Doppler frequency of the reflected electromagnetic waves is calculated and the characterization of the reflected broadband electromagnetic waves is established.

[0073] Step 1 specifically includes:

[0074] Step 1.1: Based on the high-speed plasma thickness l and the thickness d of the nth plasma layer... n and the total thickness from the first plasma layer to the nth plasma layer Solving for the electron density n of the nth layer of a high-speed plasma layer model e,n :

[0075]

[0076] In the formula, n is the sequence number of the high-speed plasma layer model, l peak This represents the distance from the target surface when the peak electron density is reached, where n = 1, 2, 3...N, and N is the total number of layers in the high-speed plasma layering model.

[0077] Step 1.2: Based on the unit charge e and electron mass m e And the vacuum permittivity ε0, based on the high-speed plasma layer stratification model in step 1.1, the electron density n of the nth layer plasma. e,n Solve for the characteristic angular frequency ω of the nth plasma layer. p,n and the characteristic frequency f of the nth plasma layer p,n :

[0078]

[0079]

[0080] Step 2 specifically includes:

[0081] Step 2.1: Based on the starting frequency f of the broadband electromagnetic wave c Given the bandwidth B, find the termination frequency f of the broadband electromagnetic wave. end =f c +B;

[0082] Step 2.2: Based on the broadband electromagnetic wave starting frequency f in Step 2.1 c and broadband electromagnetic wave termination frequency f end The frequency domain range of the broadband electromagnetic wave is obtained, and the starting frequency f of the broadband electromagnetic wave is... c to the broadband electromagnetic wave termination frequency f end Within this range, frequency domain diversity processing of broadband electromagnetic waves from high-speed plasma is performed:

[0083] When broadband electromagnetic waves are incident on high-speed plasma, the following situations occur:

[0084] Case 2.2.1: When the termination frequency f of the incident broadband electromagnetic wave end The frequency f of the outermost plasma layer of the high-speed plasma is less than that of the outermost plasma layer. p,1 At that time, broadband electromagnetic waves are reflected only in the outermost layer of high-speed plasma;

[0085] Case 2.2.2: When the peak characteristic frequency f of the high-speed plasma p,max Less than the starting frequency f of the incident broadband electromagnetic wave c At that time, broadband electromagnetic waves completely penetrate the high-speed plasma, and the broadband electromagnetic waves are reflected on the surface of the spacecraft, that is, transparent transmission is generated.

[0086] Case 2.2.3, when f p,1 <f c <f end <f p,max At that time, the broadband electromagnetic wave is incident as a whole into the high-speed plasma, with different frequency components corresponding to different incident depths, based on the diversity signal carrier frequency f. i Equal to plasma characteristic frequency f p,n Create a diversity signal, where i is the carrier frequency sequence number of the diversity signal, i = 0, 1, 2, ..., I, and I represents the total number of diversity signals obtained after broadband electromagnetic wave frequency diversity processing. I f represents the maximum diversity frequency obtained after frequency diversity processing of broadband electromagnetic waves. p,n The characteristic frequency of the nth plasma layer is f, and the carrier frequency of the diversity signal is f. i This corresponds to the characteristic frequencies of each plasma layer within the intersection range of the broadband electromagnetic wave frequency range and the characteristic frequencies of each plasma layer.

[0087] For example, let the characteristic frequencies of the plasma layers 1 to 5 be f. p,1 =0.1Hz, f p,2 =0.5Hz, f p,3 =1Hz, f p,4 =2Hz, f p,5 =5Hz, the peak characteristic frequency within the plasma is f pmax =10Hz, and the broadband electromagnetic wave frequency range is 0.3GHz to 4GHz, then the designed diversity signals are f1 = 0.5Hz, f2 = 1Hz, and f3 = 2Hz.

[0088] Case 2.2.4, when f c <f p,1 <f end <f pmax At that time, a broadband electromagnetic wave component is incident into the high-speed plasma, with different frequency components corresponding to different incident depths, based on the diversity signal carrier frequency f. i Equal to plasma characteristic frequency f p,n Create diversity signals;

[0089] For example, let the characteristic frequencies of the plasma layers 1 to 5 be f. p,1 =0.1Hz, f p,2 =0.5Hz, f p,3 =1Hz, f p,4 =2Hz, f p,5 =5Hz, the peak characteristic frequency of the high-speed plasma is f pmax =10Hz, and the broadband electromagnetic wave frequency range is 0.05GHz to 4GHz, then the designed diversity signals are f1=0.1Hz, f2=0.5Hz, f3=1Hz, and f4=2Hz.

[0090] Case 2.2.5, when f p,1 <f c <f p,max <f end When broadband electromagnetic waves are incident on the interior of high-speed plasma, some diversity signals penetrate the high-speed plasma and are transmitted to the target surface, while simultaneously generating transparent transmission and electromagnetic shielding effects.

[0091] For example, let the characteristic frequencies of the plasma layers 1 to 5 be f. p,1 =0.1Hz, f p,2 =0.5Hz, f p,3 =1Hz, f p,4 =2Hz, f p,5 =5Hz, the peak characteristic frequency within the plasma is f pmax =f p,6=10Hz, and the broadband electromagnetic wave frequency range is 0.05GHz to 12GHz, then the designed diversity signals are f1=0.1Hz, f2=0.5Hz, f3=1Hz, f4=2Hz, f5=5Hz, and f6=10Hz.

[0092] In cases 2.2.1 and 2.2.2, the frequency of the broadband electromagnetic wave does not affect the reflection result, so diversity processing is not required. In cases 2.2.3, 2.2.4, and 2.2.5, since plasma has the characteristic of intercepting electromagnetic waves with frequencies lower than the plasma's characteristic frequency, according to f... i =f p,n Design diversity signal, f p,n The characteristic frequency of the nth plasma layer is f, and the carrier frequency of the diversity signal is f. i This corresponds to the characteristic frequencies of each plasma layer within the intersection range of the broadband electromagnetic wave frequency range and the characteristic frequencies of each plasma layer.

[0093] Step 2.3: Calculate the complex permittivity ε of each plasma layer. n,i Propagation constant k n,i and intrinsic wave impedance Z n,i Based on the vacuum permittivity ε0 and the collision frequency v of the nth layer plasma p,n Based on the characteristic angular frequency ω of the nth layer plasma p,n and the carrier frequencies f of each diversity signal of the incident electromagnetic wave in step 2.2 i The complex permittivity ε of each plasma layer was obtained. n,i :

[0094] According to the high-speed plasma layering model, the characteristic frequency f in the nth plasma layer is... p,n and collision frequency v p,n The complex permittivity ε in the nth plasma layer of the high-speed plasma layer model can be calculated. n,i The complex permittivity ε in the nth layer of the high-speed plasma layer model within the homogeneous plasma medium is... n,i The calculation formula is:

[0095]

[0096] The complex permittivity ε of the nth layer plasma n,i The carrier frequencies f of the combined incident electromagnetic wave diversity signals i Given the vacuum permeability μ0, solve for the propagation constant k of the nth plasma layer. n,i The intrinsic wave impedance Z of the nth layer plasma n,i :

[0097] Dielectric constant ε n,iIt is the main parameter reflecting the polarization properties of a dielectric under the influence of an electric field. Polarization represents the relative degree to which the bonding electron cloud changes under the influence of an external electric field. It is derived from the complex permittivity ε of the nth layer plasma medium. n,i The propagation constant and intrinsic impedance of the nth plasma can be calculated from the vacuum permeability μ0 and the incident electromagnetic wave carrier frequency.

[0098]

[0099]

[0100] Step 2.4: The propagation constant k of the nth layer plasma calculated in Step 2.3. n,i The intrinsic wave impedance Z of the nth layer plasma n,i Combine the vacuum permeability μ0 and the thickness d of the nth plasma layer n The transport matrix of the nth layer plasma can be calculated using the hyperbolic sine function sinh and the hyperbolic cosine function cosh.

[0101]

[0102] Step 2.5: Based on the intrinsic wave impedance Z0 of the incident medium and the intrinsic wave impedance Z of the outermost plasma. 1,i The outermost plasma reflectance R is obtained from the plasma reflectance calculation formula. 1,i Based on the plasma transport matrix of each layer in step 2.4, calculate the reflection coefficient R between adjacent plasmas. n,i ':

[0103]

[0104] Step 2.6: Based on the plasma transport matrices of each layer in Step 2.4, calculate the single-layer transmission coefficient T of the nth plasma layer. u,i :

[0105]

[0106] Where u is the layer number of the high-speed plasma layer model;

[0107] Step 2.7: Calculate the high-speed plasma layered complex reflection coefficient: Combine the reflection coefficients R of each adjacent plasma in Step 2.5. n,i 'and the monolayer plasma transmission coefficient T in step 2.6 u,i Multiply the complex reflection coefficient of the nth plasma layer by the single-layer transmission coefficient of each plasma layer in the incident and exit paths to obtain the diversity signal carrier frequency f. i Complex reflection coefficient reflected from the nth layer of plasma into free space:

[0108]

[0109] Step 2.8: Based on the carrier frequency f of each diversity signal i Solve for the reflection coefficients of each plasma layer obtained from the incident high-speed plasma:

[0110] R all,i =[R 1,i R 2,i R 3,i …R n,i ]

[0111] Among them, R n,i This indicates that the diversity signal is in the form of a carrier frequency f. i The complex reflection coefficient, R, of the nth layer plasma reflected into free space. all,i This indicates that the diversity signal is in the form of a carrier frequency f. i The reflection coefficient matrix of each plasma layer is given, where i is the carrier frequency sequence number of the diversity signal, i = 0, 1, 2, ..., I, and I represents the total number of diversity signals obtained after broadband electromagnetic wave frequency diversity processing.

[0112] Step 3 specifically includes:

[0113] Step 3.1: Calculate the Doppler frequencies of each diversity signal coupling: based on the velocity v of each layer of the high-speed plasma flow field. n Solve for the frequency f of each diversity signal. i The corresponding coupled Doppler frequency f d,i :

[0114]

[0115] Step 3.2: Based on the coupling Doppler frequency f in Step 3.1 d,i Solve for the reflected electromagnetic wave E of the nth layer of high-speed plasma. R (t,n): Suppose that the broadband electromagnetic wave can be divided into I diversity signals. Based on the spatial distribution characteristics of the reflection coefficients of each diversity signal in the high-speed plasma, the broadband electromagnetic wave reflection model of the nth layer of the high-speed plasma is solved by vector accumulation as follows:

[0116]

[0117] Among them, R n,i Let |R| be the reflection coefficient of the i-th diversity signal at the n-th layer. n,i | indicates the magnitude of the reflection coefficient. This represents the phase modulation coefficient of the reflection coefficient on the incident electromagnetic signal;

[0118] Step 3.3: Calculate the electromagnetic wave E reflected by high-speed plasma under a large bandwidth system. R(t): Broadband electromagnetic wave reflection model E based on the nth layer plasma of the high-speed plasma in step 3.2. R The electromagnetic waves reflected by high-speed plasma under a large bandwidth regime (t,n) are shown below:

[0119]

[0120] A modeling system for high-speed plasma reflected electromagnetic waves under a large bandwidth regime includes:

[0121] High-speed plasma parameter model module: Establishes a high-speed plasma stratification model and obtains the high-speed plasma stratified electron density n. e,n Characteristic angular frequency ω p,n Characteristic frequency f p,n Step 1 of a modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system;

[0122] Layered Reflection Coefficient Calculation Module: Based on the high-speed plasma layering model, a high-speed plasma layered reflection analysis model under a large bandwidth system is established to calculate the diversity signal at the carrier frequency f. i The complex reflection coefficient R reflected from the nth layer plasma into free space n,i Step 2 of a modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system;

[0123] High-speed plasma electromagnetic wave reflection module under large bandwidth regime: Based on the hierarchical reflection analysis model of high-speed plasma under large bandwidth regime, the electromagnetic wave reflection characterization of high-speed plasma under large bandwidth regime is solved, and the electromagnetic wave E reflected by high-speed plasma under large bandwidth regime is obtained. R (t), step 3 of a modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system.

[0124] A modeling device for high-speed plasma reflected electromagnetic waves under a large bandwidth system includes:

[0125] Memory: Used to store the computer program that implements the modeling method for high-speed plasma reflection electromagnetic waves under a large bandwidth system;

[0126] Processor: Used to implement the modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system when executing the computer program.

[0127] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or any conventional processor. The processor is the control center of the device for modeling high-speed plasma reflected electromagnetic waves under a high-bandwidth system, connecting various parts of the device through various interfaces and lines.

[0128] When the processor executes the computer program, it implements the steps of the above-mentioned modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system, such as: establishing a high-speed plasma layer model; establishing a high-speed plasma layer reflection analysis model under a large bandwidth system based on the high-speed plasma layer model; solving the characterization of high-speed plasma reflected electromagnetic waves under a large bandwidth system based on the high-speed plasma layer reflection analysis model under a large bandwidth system; thus realizing the modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system.

[0129] Alternatively, when the processor executes the computer program, it implements the functions of each module in the above system, such as: a high-speed plasma parameter model module: establishing a high-speed plasma layer model and obtaining the high-speed plasma layer electron density, characteristic angular frequency, and characteristic frequency; a layer reflection coefficient calculation module: establishing a high-speed plasma layer reflection analysis model under a large bandwidth regime based on the high-speed plasma layer model, and calculating the actual complex reflection coefficients of each layer of the high-speed plasma layer model; a high-speed plasma reflected electromagnetic wave module under a large bandwidth regime: solving the characterization of high-speed plasma reflected electromagnetic waves under a large bandwidth regime based on the high-speed plasma layer reflection analysis model under a large bandwidth regime, and obtaining the reflected electromagnetic waves of the high-speed plasma; and outputting the results of the modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth regime.

[0130] For example, the computer program can be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing preset functions. These instruction segments describe the execution process of the computer program in the device of the modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system. For example, the computer program can be divided into a high-speed plasma parameter model module, a layered reflection coefficient calculation module, and a high-speed plasma reflected electromagnetic wave module under a large bandwidth system. The specific functions of each module are as follows: High-speed plasma parameter model module: establishes a high-speed plasma layered model and obtains the high-speed plasma layered electron density, characteristic angular frequency, and characteristic frequency; Layered reflection coefficient calculation module: establishes a high-speed plasma layered reflection analysis model under a large bandwidth system based on the high-speed plasma layered model and calculates the actual complex reflection coefficients of each layer of plasma in the high-speed plasma layered model; High-speed plasma reflected electromagnetic wave module under a large bandwidth system: solves the characterization of high-speed plasma reflected electromagnetic waves under a large bandwidth system based on the high-speed plasma layered reflection analysis model under a large bandwidth system, obtains the reflected electromagnetic waves of the high-speed plasma, and outputs the results of the modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system.

[0131] The device described in the modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system can be a computing device such as a desktop computer, laptop, handheld computer, or cloud server. This device may include, but is not limited to, processors and memory. Those skilled in the art will understand that the above is an example of a device for a modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system, and does not constitute a limitation on the device for such a method. It may include more components than described above, or combine certain components, or use different components. For example, the device for a modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system may also include input / output devices, network access devices, buses, etc.

[0132] The memory can be used to store the computer program and / or modules. The processor implements various functions of the device for modeling high-speed plasma reflected electromagnetic waves under a large bandwidth system by running or executing the computer program and / or modules stored in the memory and calling the data stored in the memory.

[0133] The memory may primarily include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a given function (such as sound playback or image playback). The data storage area may store data created based on the use of the phone (such as audio data or a phonebook). Furthermore, the memory may include high-speed random access memory (RAM) and non-volatile memory, such as hard disks, RAM, plug-in hard disks, SmartMediaCards (SMC), Secure Digital (SD) cards, flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0134] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system.

[0135] If the system integration module / unit for modeling high-speed plasma reflected electromagnetic waves under a large bandwidth system is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium.

[0136] This invention implements all or part of the process in the above-described modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system. It can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium. When executed by a processor, the computer program can implement the steps of the above-described modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or a preset intermediate form, etc.

[0137] The computer-readable storage medium may include: any entity or device capable of carrying the computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0138] It should be noted that the content contained in the computer-readable storage medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable storage medium does not include electrical carrier signals and telecommunication signals.

[0139] It should be noted that embodiments of the present invention can be implemented using hardware, software, or a combination of both. The hardware portion can be implemented using dedicated logic; the software portion can be stored in memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated hardware.

[0140] Those skilled in the art will understand that the above-described devices and methods can be implemented using computer-executable instructions and / or included in processor control code, for example, such code provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuitry of semiconductors such as very large-scale integrated circuits or gate arrays, logic chips, transistors, etc., or programmable hardware devices such as field-programmable gate arrays, programmable logic devices, etc., or by software executed by various types of processors, or by a combination of the above-described hardware circuitry and software, such as firmware.

[0141] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A modeling method for electromagnetic waves reflected by high-speed plasma under a large bandwidth system, characterized in that, Includes the following steps: Step 1: Establish a high-speed plasma layering model; Step 2: Establish a high-speed plasma layered reflection analysis model under a large bandwidth system based on the high-speed plasma layering model, as detailed below: Step 2.1: Based on the starting frequency of the broadband electromagnetic wave bandwidth Solve for the termination frequency of broadband electromagnetic waves. ; Step 2.2: Based on the broadband electromagnetic wave starting frequency in Step 2.1 and broadband electromagnetic wave termination frequency The frequency domain range of broadband electromagnetic waves was obtained, and the starting frequency of the broadband electromagnetic waves was... To the broadband electromagnetic wave termination frequency Within this range, frequency domain diversity processing of broadband electromagnetic waves from high-speed plasma is performed: When broadband electromagnetic waves are incident on high-speed plasma, the following situations occur: Case 2.2.1: When the termination frequency of the incident broadband electromagnetic wave... Less than the characteristic frequency of the outermost plasma of high-speed plasma At that time, broadband electromagnetic waves are reflected only in the outermost layer of high-speed plasma; Case 2.2.2, when the high-speed plasma peak characteristic frequency is less than the start frequency of the incident broadband electromagnetic wave , the broadband electromagnetic wave is completely penetrated by the high-speed plasma, and the broadband electromagnetic wave is reflected on the surface of the vehicle; Situation 2.2.3, when At that time, the broadband electromagnetic wave is incident as a whole into the high-speed plasma, with different frequency components corresponding to different incident depths, based on the diversity signal carrier frequency. equal to plasma characteristic frequency Create diversity signals, where i The carrier frequency sequence number of the diversity signal. i =0,1,2,…, I , I This represents the total number of diversity samples obtained after frequency diversity processing of broadband electromagnetic waves. This represents the maximum diversity frequency obtained after frequency diversity processing of broadband electromagnetic waves. For the first n characteristic frequencies of layered plasmas, carrier frequencies of diversity signals This corresponds to the characteristic frequencies of each plasma layer within the intersection range of the broadband electromagnetic wave frequency range and the characteristic frequencies of each plasma layer. Case 2.2.4, when a broadband electromagnetic wave is incident into a high-speed plasma, different frequency components correspond to different incident depths, and a diversity signal is created according to the diversity signal carrier frequency equal to the characteristic frequency of the plasma ; Situation 2.2.5, when When broadband electromagnetic waves are incident on the interior of high-speed plasma, some diversity signals penetrate the high-speed plasma and are transmitted to the target surface, while simultaneously generating transparent transmission and electromagnetic shielding effects. Step 2.3: Calculate the complex permittivity of each plasma layer. Propagation constant and intrinsic impedance According to the vacuum permittivity and the n Layer plasma collision frequency Based on the first n characteristic angular frequency of layer plasma and the carrier frequencies of each diversity signal of the incident electromagnetic wave in step 2.2 The complex permittivity of each plasma layer was obtained. : By the n Complex permittivity of layer plasma Combined carrier frequencies of the diversity signals of the incident electromagnetic wave and vacuum permeability Solve the first... n Plasma propagation constant and the n Intrinsic impedance of layer plasma : Step 2.

4. The first n layer plasma propagation constant , the first n layer plasma intrinsic wave impedance with the vacuum permeability and the first n layer plasma thickness , the transmission matrix of the first n layer plasma is calculated according to the hyperbolic sine function sinh and the hyperbolic cosine function cosh: Step 2.

5. Incident medium-based intrinsic wave impedance and outermost plasma intrinsic wave impedance outermost plasma reflection coefficient from plasma reflection coefficient calculation formula reflection coefficient between adjacent plasma layers from Step 2.4 plasma transmission matrices : Step 2.6: Based on the plasma transport matrices of each layer in Step 2.4, obtain the... n Single-layer transmission coefficient of plasma : wherein, is the layer number of the high-speed plasma layering model; Step 2.7: Calculate the complex reflection coefficient of high-speed plasma layers: Combine the reflection coefficients between adjacent plasma layers from Step 2.

5. And the monolayer plasma transmission coefficient in step 2.6 , will the n Multiplying the complex reflection coefficient of the plasma layers by the single-layer transmission coefficients of each plasma layer in the incident and exit paths, the carrier frequency of the diversity signal is calculated. By the n Complex reflection coefficient of layered plasma reflected into free space: Step 2.

8. Process each diversity signal based on step 2.2 to carrier frequency Incident high speed plasma and step 2.7 layered reflection coefficient calculation method, the reflection coefficient of each layer plasma is solved: in, Indicates diversity signal in carrier frequency By the n The complex reflection coefficient of a layer plasma reflected into free space. Indicates diversity signal in carrier frequency The reflection coefficient matrix of each plasma layer, i The carrier frequency sequence number of the diversity signal. i =0,1,2,…, I , I This represents the total number of diversity samples obtained after frequency diversity processing of broadband electromagnetic waves. Step 3: Solve the electromagnetic wave characterization of high-speed plasma reflection under a large bandwidth system based on the high-speed plasma layered reflection analysis model, as detailed below: Step 3.1, Calculate Doppler frequency of each diversity signal coupling: according to the high-speed plasma each layer flow field velocity , solve the carrier frequency of each diversity signal corresponding coupling Doppler frequency : Step 3.2, solving the high-speed plasma based on the coupled Doppler frequency in step 3.1 , solving the high-speed plasma n , solving the high-speed plasma : assuming that a broadband electromagnetic wave can be formed I , solving the high-speed plasma n , solving the high-speed plasma wherein R n,i is the first i layer of the first n diversity signal, denotes the amplitude of the reflection coefficient, denotes the phase modulation coefficient of the reflection coefficient on the incident electromagnetic signal; Step 3.

3. Calculation of high-speed plasma reflected electromagnetic wave under large bandwidth regime : Based on the high-speed plasma model in step 3.2 n Layered plasma wideband electromagnetic wave reflection model The high-speed plasma reflected electromagnetic wave under large bandwidth regime is obtained as follows: 。 2. The modeling method of claim 1, wherein, Step 1 specifically includes: Step 1.1: Based on the high-speed plasma thickness , No. n Plasma layer thickness and from the first layer of plasma to the second layer n Total thickness of the plasma layer Solving the high-speed plasma layering model n Layer plasma electron density : In the formula, n is the layer number of the high-speed plasma stratified model, represents the distance from the target surface when the peak electron density is reached, n = 1, 2, 3… N , N is the total number of layers of the high-speed plasma stratified model; Step 1.

2. Calculate the electron mass meand the vacuum permittivity ε0based on the unit charge e e Step 1.

3. Calculate the plasma electron density nei based on the step 1.1 high-speed plasma stratification model n Step 1.

4. Calculate the plasma characteristic angular frequency ωpi based on the step 1.1 high-speed plasma stratification model n Step 1.

5. Calculate the plasma characteristic frequency fpi based on the step 1.1 high-speed plasma stratification model n :​​​​​ 。 3. A modeling system for high-speed plasma reflection electromagnetic waves under a large bandwidth system, characterized in that, The method described in any one of claims 1-2 is used to implement the method, including: High-speed plasma parameter model module: a high-speed plasma layered model is established to obtain high-speed plasma layered electron density , characteristic angular frequency , characteristic frequency ; The layered reflection coefficient calculation module: based on the high-speed plasma layered model, a high-speed plasma layered reflection analysis model under a large bandwidth system is established, and the diversity signal is calculated at the carrier frequency by the first n The complex reflection coefficient of the layer plasma reflected to the free space ; The high-speed plasma reflected electromagnetic wave module under the large bandwidth system: based on the high-speed plasma layered reflection analysis model under the large bandwidth system, the high-speed plasma reflected electromagnetic wave under the large bandwidth system is solved, and the high-speed plasma reflected electromagnetic wave under the large bandwidth system is obtained .

4. A modeling device for high speed plasma reflection of electromagnetic waves in a large bandwidth regime, characterized by, include: Memory: Used to store a computer program for implementing a modeling method for high-speed plasma reflection electromagnetic waves under a large bandwidth system as described in any one of claims 1-2; Processor: Used to implement the modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system as described in any one of claims 1-2 when executing the computer program.

5. A computer readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of a modeling method for high-speed plasma reflected electromagnetic waves under a large bandwidth system as described in any one of claims 1-2.

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