Simulation method and device for terahertz wave transmission characteristics of plasma covered flat plate

Abstract

The invention relates to the field of optics, in particular to a method and a device for simulating terahertz wave transmission characteristics of a plasma covered flat plate. The method comprises the following steps: firstly, constructing a two-dimensional model through geometric parameters of a plasma covering flat plate, endowing corresponding material attributes to the two-dimensional model to obtain a physical model, and substituting plasma characteristic parameters into a plasma region of the physical model to obtain a simulation model of terahertz wave transmission characteristics of the plasma covering flat plate; the method is used for simulating the transmission condition of the terahertz wave of the plasma covering flat plate, and then a simulation model of the transmission characteristics of the terahertz wave of the plasma covering flat plate is used for carrying out analogue simulation calculation to obtain the electric field distribution of the terahertz wave passing through the plasma covering flat plate. Compared with the prior art, the transmission characteristics of the terahertz waves passing through the plasma covering flat plate can be indirectly determined through the terahertz wave electric fields of the incident port and the emergent port, and researchers can be helped to rapidly know the transmission characteristics of the terahertz waves passing through the plasma covering flat plate.

Description

Technical Field

[0001] The present invention relates to the field of optics, and in particular to a method and a device for simulating terahertz wave transmission characteristics of a plasma-covered flat plate. Background Art

[0002] When electromagnetic waves encounter a plasma sheath during propagation, they are absorbed and attenuated, and deflection, delay, phase shift and other effects occur. In severe cases, a "black barrier" appears. The appearance of a "black barrier" brings great difficulties to the measurement, control and communication of high-speed aircraft.

[0003] In the related art, the terahertz wave transmission measurement system is often complex and has a small dynamic range, which leads to inaccurate simulation results of the terahertz wave transmission characteristics of the plasma covered plate.

[0004] Based on this, a simulation method and device for the terahertz wave transmission characteristics of a plasma-covered flat plate are urgently needed to solve the technical problem of how to quickly grasp the terahertz wave transmission characteristics of a plasma-covered flat plate. Summary of the invention

[0005] In order to solve the technical problem of how to quickly grasp the terahertz wave transmission characteristics of a plasma-covered flat plate, an embodiment of the present invention provides a method and device for simulating the terahertz wave transmission characteristics of a plasma-covered flat plate.

[0006] In a first aspect, an embodiment of the present invention provides a method for simulating terahertz wave transmission characteristics of a plasma-covered flat plate, comprising:

[0007] Acquire geometric parameters of the plasma-covered plate and characteristic parameters of the plasma; wherein the characteristic parameters include the electron density and collision frequency of the plasma;

[0008] Based on the geometric parameters, a two-dimensional model of the plasma-covered flat plate is determined, and corresponding material properties are assigned to the two-dimensional model to obtain a physical model; wherein the physical model includes a plasma region, a free space region, and a flat plate material region, the free space region, the plasma region, and the flat plate material region are sequentially connected, the free space region is an entrance region and a reflection exit region of the terahertz wave, and the flat plate material region is a transmission exit region of the terahertz wave;

[0009] Bringing the characteristic parameters into the plasma region to obtain a simulation model of terahertz wave transmission characteristics of a plasma-covered flat plate;

[0010] The simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate is used to perform simulation calculations to obtain the electric field distribution of the plasma-covered flat plate; wherein the electric field distribution includes the electric fields in different directions of the incident port and the electric field of the exit port;

[0011] The terahertz wave transmission characteristics of the plasma covered slab are determined based on the electric fields in different directions of the incident port and the electric field of the exit port.

[0012] In a second aspect, an embodiment of the present invention further provides a device for simulating the transmission characteristics of a plasma-covered flat plate terahertz wave, comprising:

[0013] An acquisition module, used to acquire geometric parameters of the plasma-covered plate and characteristic parameters of the plasma; wherein the characteristic parameters include the electron density and collision frequency of the plasma;

[0014] A first model building module is used to determine the two-dimensional model of the plasma-covered flat plate based on the geometric parameters, and assign corresponding material properties to the two-dimensional model to obtain a physical model; wherein the physical model includes a plasma region, a free space region and a flat plate material region, the free space region, the plasma region and the flat plate material region are sequentially connected, the free space region is an entrance region and a reflection exit region of the terahertz wave, and the flat plate material region is a transmission exit region of the terahertz wave;

[0015] A second model building module is used to bring the characteristic parameters into the plasma region to obtain a simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate;

[0016] A first data processing module is used to perform simulation calculations using a simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate to obtain an electric field distribution of the plasma-covered flat plate; wherein the electric field distribution includes electric fields in different directions of an incident port and an electric field at an exit port;

[0017] The second data processing module is used to determine the terahertz wave transmission characteristics of the plasma covered slab based on the electric fields in different directions of the incident port and the electric field of the exit port.

[0018] In a third aspect, an embodiment of the present invention further provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method described in any embodiment of the present invention is implemented.

[0019] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to execute the method described in any embodiment of the present invention.

[0020] The embodiment of the present invention provides a method and device for simulating terahertz wave transmission characteristics of a plasma-covered flat plate. First, a two-dimensional model is constructed according to geometric parameters of a plasma-covered flat plate, and corresponding material properties are assigned to the two-dimensional model to obtain a physical model. Characteristic parameters are introduced into a plasma region of the physical model, and preset air dielectric constants and material dielectric constants are introduced into a free space region and a flat plate material region in turn to obtain a simulation model of terahertz wave transmission characteristics of a plasma-covered flat plate, so as to simulate the state of terahertz wave transmission of a plasma-covered flat plate. Finite element simulation calculation is then performed using the simulation model of terahertz wave transmission characteristics of a plasma-covered flat plate to obtain terahertz wave electric field distribution of the plasma-covered flat plate, and then the terahertz wave transmission characteristics of the plasma-covered flat plate are indirectly determined through the terahertz wave electric fields of an incident port and an exit port. Compared with related testing technologies, the present invention can quickly grasp the terahertz wave transmission characteristics of a plasma-covered flat plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a flow chart of a method for simulating terahertz wave transmission characteristics of a plasma-covered flat plate provided by an embodiment of the present invention;

[0023] Figure 2 is a schematic diagram of a terahertz wave transmission model in a plasma covered flat plate provided by an embodiment of the present invention;

[0024] Figure 3 is a schematic diagram of an externally introduced non-uniform plasma electron density distribution provided by an embodiment of the present invention;

[0025] Figure 4 is a schematic diagram of electric field distribution of terahertz waves in various regions when the flat plate material provided by an embodiment of the present invention is gold;

[0026] Figure 5 is a schematic diagram of electric field distribution of terahertz waves in various regions when the flat plate material is SiO2 provided in an embodiment of the present invention;

[0027] Figure 6 is a schematic diagram of a transmission characteristic curve of a terahertz wave when the flat plate material provided by an embodiment of the present invention is gold;

[0028] Figure 7is a schematic diagram of a transmission characteristic curve of a terahertz wave when the flat plate material is SiO2 provided in an embodiment of the present invention;

[0029] Figure 8 is a schematic diagram of a transmission characteristic curve when a 1 THz terahertz wave is incident on a plasma-covered gold flat plate material at different incident angles provided by an embodiment of the present invention;

[0030] Fig. 9 is a schematic diagram of a transmission characteristic curve when a 1 THz terahertz wave is incident on a plasma-covered SiO2 flat plate material at different incident angles provided by an embodiment of the present invention;

[0031] Fig.10 is a hardware architecture diagram of an electronic device provided by an embodiment of the present invention;

[0032] Fig.11 It is a structural diagram of a simulation device for terahertz wave transmission characteristics of a plasma-covered flat plate provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] Please refer to Figure 1 The embodiment of the present invention provides a method for simulating terahertz wave transmission characteristics of a plasma-covered flat plate, the method comprising:

[0035] Step 100: obtaining geometric parameters of the plasma-covered plate and characteristic parameters of the plasma; wherein the characteristic parameters include the electron density and collision frequency of the plasma;

[0036] Step 102: Based on the geometric parameters, determine a two-dimensional model of a plasma-covered flat plate, and assign corresponding material properties to the two-dimensional model to obtain a physical model; wherein the physical model includes a plasma region, a free space region, and a flat plate material region, the free space region, the plasma region, and the flat plate material region are sequentially connected, the free space region is an entrance region and a reflection exit region of the terahertz wave, and the flat plate material region is a transmission exit region of the terahertz wave;

[0037] Step 104: Bring the characteristic parameters into the plasma region to obtain a simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate;

[0038] Step 106: Perform finite element simulation calculation using a simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate to obtain the electric field distribution of the terahertz wave after passing through the plasma-covered flat plate; wherein the electric field distribution includes the electric fields in different directions of the incident port and the electric field of the exit port;

[0039] Step 108: Determine the terahertz wave transmission characteristics of the plasma covered slab based on the electric fields in different directions of the incident port and the electric field of the exit port.

[0040] In an embodiment of the present invention, a two-dimensional model is first constructed according to the geometric parameters of a plasma-covered flat plate, and corresponding material properties are assigned to the two-dimensional model to obtain a physical model, and characteristic parameters are brought into the plasma region of the physical model, and the preset dielectric constant of air and the dielectric constant of the material are brought into the free space region and the flat plate material region in turn to obtain a simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate, so as to simulate the condition of terahertz wave transmission of the plasma-covered flat plate, and then the simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate is used to perform finite element simulation calculation to obtain the terahertz wave electric field distribution of the plasma-covered flat plate, and then the terahertz wave transmission characteristics of the plasma-covered flat plate are indirectly determined by the terahertz wave electric fields of the incident port and the exit port. Compared with related testing technologies, the present invention can quickly grasp the terahertz wave transmission characteristics of the plasma-covered flat plate.

[0041] Described below Figure 1 How the various steps are performed.

[0042] For step 100:

[0043] In one embodiment of the present invention, characteristic parameters of plasma can be collected by a laser Thomson scattering measurement system. The Thomson scattering (TS) signal collection system consists of a lens combination, a linear fiber bundle, a spectrometer (TGS) with three gratings, and a charge coupled camera (ICCD). The fiber collection direction is at a 90-degree angle to the laser direction and the plasma beam axis. A group of convex lens combinations set in front of the optical fiber can focus the laser-plasma interaction area to the fiber entrance. The Thomson scattering signal collected by the optical fiber is transmitted to the TGS system, passes through the gratings, lenses and other optical devices inside the TGS system, and finally forms an image (spectrum) on the ICCD camera. In order to avoid Rayleigh scattering from the air and reflections from the surfaces of other objects, the collection end of the optical fiber and the collection lens are placed in a dark room. The distribution of characteristic parameters of plasma can be directly obtained by measuring the laser Thomson scattering of plasma.

[0044] In one embodiment of the present invention, the electron density of the plasma can be measured by a Langmuir probe, by inserting a very small electrode into the plasma, applying a certain voltage, and then measuring the relationship between the current passing through and the applied voltage. By analyzing the special points on the voltage-current characteristic curve, the electron density of the plasma can be calculated.

[0045] In one embodiment of the present invention, the geometric parameters of the plasma-covered flat plate can be collected by a laser scanning device. First, ensure that the laser beam can cover the entire area of ​​the flat plate to be measured. Then start scanning and record the reflected light signal. In the data processing stage, according to the angle, time and other parameters of the laser scanning, combined with the optical property model of the plasma, the coordinates of each point on the flat plate surface are calculated, thereby obtaining the geometric parameters of the flat plate, such as length, width, flatness, etc.

[0046] Regarding step 102:

[0047] In one embodiment of the present invention, according to the collected geometric parameters, including the length, width, and thickness of the plate, a suitable two-dimensional modeling software (such as CAD) is selected. A new two-dimensional model file is created in the software, and the unit system of the model is set to ensure that it is consistent with the unit of the geometric parameters. Then the corresponding material properties are assigned to the two-dimensional model to obtain a physical model. Those skilled in the art can customize the material properties according to actual usage, such as ceramics and copper.

[0048] like Figure 2 As shown, in one embodiment of the present invention, the free space region, the plasma region and the flat plate material region are connected in sequence, the free space region is the entrance region of the terahertz wave, the flat plate material region is the exit region of the terahertz wave, and the two sides of each region are set with periodic boundary conditions to ensure that the infinite flat plate is covered by the infinite plasma region. The starting end of the free space region away from the plasma region is used as the entrance of the terahertz wave, and the ending end of the flat plate material region away from the plasma region is used as the exit of the terahertz wave.

[0049] Regarding step 104:

[0050] In one embodiment of the present invention, the characteristic parameters are brought into the plasma region to obtain a simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate, which is used to simulate the situation of terahertz wave transmission of the plasma-covered flat plate. For the case where the lateral dimensions of the plasma region and the flat plate region are much larger than the terahertz wave beam diameter, it can be considered that the plasma and flat plate regions are infinite in the lateral direction. Therefore, when calculating, the two sides of the model are usually set as periodic boundary conditions. In addition to the plasma region, the free space region and the flat plate material region are selected and set for the corresponding parts of the material in the model. By defining variables, the plasma electron density (the collision frequency is sometimes a certain value and sometimes a distribution data) obtained by external measurement or simulation is imported into the blue area in the model in the form of an interpolation function. The wall is layered and divided into appropriate grids.

[0051] like Figure 3 As shown, in this embodiment, the plasma region is rectangular, and different colors are used to represent different electric field strengths, and the electric field strength increases from blue to red.

[0052] Regarding step 106:

[0053] In one embodiment of the present invention, step 106 may specifically include:

[0054] Based on the characteristic parameters, the equivalent dielectric constant of the plasma is determined;

[0055] Solve Maxwell's equations based on the equivalent dielectric constant;

[0056] Based on Maxwell's equations, the electric field distribution of terahertz waves is determined.

[0057] In this embodiment, the equivalent dielectric constant is determined by the following formula:

[0058]

[0059] In the formula, ε p is the equivalent dielectric constant, ε r is the relative dielectric constant, ε0 is the vacuum dielectric constant, ν is the collision frequency, ω is the angular frequency of the terahertz wave, j is the operator of the imaginary number, ω pe is the angular frequency of the plasma; n e is the electron density; e is the electron charge; m e The mass of the electron.

[0060] In this embodiment, Maxwell's equations are:

[0061]

[0062] In the formula, ε pis the equivalent dielectric constant, j is an imaginary operator, ω is the angular frequency of the terahertz wave, is the magnetic field intensity vector, is the electric field strength vector.

[0063] In this embodiment, the terahertz electromagnetic wave propagating in the plasma propagates along the z-axis of the spatial coordinate axis, and the electric field direction is along the x-axis and y-axis of the spatial coordinate axis. In addition, in a plasma under low pressure and low temperature conditions, the collision frequency of the plasma is much smaller than the angular frequency of the terahertz wave, so the plasma can be regarded as a collision-free medium.

[0064] When electromagnetic waves propagate in low-temperature plasma, the electric field distribution is determined by the following formula:

[0065]

[0066] In the formula, μ r is the relative magnetic permeability of the plasma, ε r is the relative dielectric constant, ε0 is the vacuum dielectric constant, ω is the angular frequency of the terahertz wave, j is the operator of the imaginary number, ω pe is the angular frequency of the plasma, σ is the conductivity, is the electric field vector.

[0067] In this embodiment, when electromagnetic waves are transmitted in high-temperature plasma, the collision frequency of the plasma is close to the angular frequency of the terahertz wave, and the plasma is considered as a collision medium. Therefore, when calculating the electric field distribution, the influence of the collision frequency of the plasma on the electric field distribution is considered.

[0068] When the plasma is at a high temperature, the electric field distribution is determined by the following formula:

[0069]

[0070] In the formula, μ r is the relative magnetic permeability of the plasma, ε r is the relative dielectric constant, ε0 is the vacuum dielectric constant, ν is the collision frequency, ω is the angular frequency of the terahertz wave, j is the imaginary operator, ω pe is the angular frequency of the plasma, σ is the conductivity, is the electric field vector.

[0071] like Figure 4 As shown, in this embodiment, when the flat plate material is gold, the simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate is used to perform simulation calculations to obtain the electric field distribution of the plasma-covered flat plate, and different colors are used to represent different electric field intensities, and the electric field intensity increases from blue to red, where the incident wave is magenta, the reflected wave is blue, and the transmitted wave is green.

[0072] like Figure 5 As shown, in this embodiment, when the flat plate material is SiO2, the simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate is used to perform simulation calculations to obtain the electric field distribution of the plasma-covered flat plate, and different colors are used to represent different electric field strengths, and the electric field strength increases from blue to red, wherein the incident wave is magenta, the reflected wave is blue, and the transmitted wave is green.

[0073] In one embodiment of the present invention, the above steps regard the plasma as an equivalent dielectric whose conductivity is zero.

[0074] Regarding step 108:

[0075] In one embodiment of the present invention, the transmission characteristics of the plasma-covered flat plate terahertz wave include transmission characteristics and reflection characteristics. By comparing the electric field of the exit port with the electric field of the incident port, the transmittance (transmission characteristic) of the terahertz wave passing through the plasma-covered flat plate material can be obtained. By comparing the electric field in the direction of the incident port with the electric field in the direction of the incident port, the reflectivity (reflection characteristic) of the terahertz wave reflected by the plasma-covered flat plate material can be obtained. In addition, the absorption curve of the terahertz wave absorbed by the plasma and the flat plate material itself can be calculated according to the law of conservation of energy. The principle is that in a closed system, energy will neither be generated nor disappear out of thin air. It will only be converted from one form to another, or transferred from one object to another, while the total amount remains unchanged. In a system where the terahertz wave interacts with the plasma and the flat plate material, the energy carried by the terahertz wave is the input energy.

[0076] like Figure 6 As shown in the figure, in this embodiment, when the flat material is gold, the transmission characteristic curve of the terahertz wave, it can be seen from the figure that the reflectivity and transmittance fluctuate less with the change of the terahertz wave frequency, that is, when the flat material is gold, the reflectivity and transmittance are less affected by the terahertz wave frequency, where the green curve is the transmission curve and the blue curve is the reflectivity curve. At the same time, the reflectivity is close to 1, while the transmittance is close to 0. The reflectivity of the low-frequency part is less than 1 due to the absorption of the plasma, and the red absorption rate corresponding to the low-frequency part is not 0.

[0077] like Figure 7As shown in the figure, in this embodiment, the transmission characteristic curve of the terahertz wave when the flat material is SiO2, it can be seen from the figure that the reflectivity and transmittance fluctuate less with the change of the terahertz wave frequency, that is, when the flat material is SiO2, the reflectivity and transmittance are less affected by the terahertz wave frequency, where the green curve is the transmittance curve and the blue curve is the reflectivity curve. At the same time, the reflectivity is greater than 0, while the transmittance is less than 1, and the reflection and absorption of the terahertz wave by the low-frequency part of the plasma together lead to the reduction of the terahertz wave transmittance.

[0078] like Figure 8 As shown in the figure, in this embodiment, when the plate material is gold, and 1THz terahertz waves are incident on the plasma covered plate at different incident angles, its transmittance is almost not affected by the incident angle, and its reflectivity fluctuates greatly when the incident angle reaches 85° or more. The green curve is the transmittance curve, and the blue curve is the reflectivity curve.

[0079] like Fig. 9 As shown, in this embodiment, when the flat plate material is SiO2, and 1THz terahertz waves are incident on the plasma covered flat plate at different incident angles, its transmittance decreases with the increase of the incident angle. Before the incident angle reaches 85°, its reflectivity increases with the increase of the incident angle. Before the incident angle reaches 85°, its reflectivity decreases with the increase of the incident angle, and the fluctuation amplitude is relatively large. Among them, the green curve is the transmission curve, and the blue curve is the reflectivity curve.

[0080] like Fig.10 , Fig.11 As shown, an embodiment of the present invention provides a device for simulating the transmission characteristics of terahertz waves of a plasma-covered flat plate. The device embodiment can be implemented by software, or by hardware or a combination of software and hardware. From the hardware level, Fig.10 As shown, it is a hardware architecture diagram of an electronic device where a device for simulating the transmission characteristics of terahertz waves of a plasma-covered flat plate provided by an embodiment of the present invention is located. Fig.10 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 messages, etc. Taking software implementation as an example, Fig.11 As shown, as a device in a logical sense, the CPU of the electronic device in which it is located reads the corresponding computer program in the non-volatile memory into the internal memory and runs it.

[0081] like Fig.11 As shown, this embodiment provides a device for simulating the transmission characteristics of terahertz waves of a plasma-covered flat plate, the device comprising:

[0082] An acquisition module 110 is used to acquire geometric parameters of the plasma-covered plate and characteristic parameters of the plasma; wherein the characteristic parameters include the electron density and collision frequency of the plasma;

[0083] A first model building module 112 is used to determine the two-dimensional model of the plasma-covered flat plate based on the geometric parameters, and assign corresponding material properties to the two-dimensional model to obtain a physical model; wherein the physical model includes a plasma region, a free space region and a flat plate material region, the free space region, the plasma region and the flat plate material region are sequentially connected, the free space region is an entrance region and a reflection exit region of the terahertz wave, and the flat plate material region is a transmission exit region of the terahertz wave;

[0084] A second model building module 114 is used to bring the characteristic parameters into the plasma region to obtain a simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate;

[0085] A first data processing module 116 is used to perform simulation calculations using a simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate to obtain an electric field distribution of the plasma-covered flat plate; wherein the electric field distribution includes electric fields in different directions of an incident port and an electric field at an exit port;

[0086] The second data processing module 118 is used to determine the terahertz wave transmission characteristics of the plasma covered slab based on the electric fields in different directions of the incident port and the electric field of the exit port.

[0087] In an embodiment of the present invention, the acquisition module 110 can be used to execute step 100 in the above method embodiment, the first model building module 112 can be used to execute step 102 in the above method embodiment, the second model building module 114 can be used to execute step 104 in the above method embodiment, the first data processing module 116 can be used to execute step 106 in the above method embodiment, and the second data processing module 118 can be used to execute step 108 in the above method embodiment.

[0088] In one embodiment of the present invention, the simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate is used to perform simulation calculations to obtain the electric field distribution of the plasma-covered flat plate, including:

[0089] Based on the characteristic parameters, determining the equivalent dielectric constant of the plasma;

[0090] Solving Maxwell's equations based on the equivalent dielectric constant;

[0091] Based on the Maxwell equations, the electric field distribution of the terahertz wave is determined.

[0092] In one embodiment of the present invention, the equivalent dielectric constant is determined by the following formula:

[0093]

[0094] In the formula, ε p is the equivalent dielectric constant, ε r is the relative dielectric constant, ε0 is the vacuum dielectric constant, ν is the collision frequency, ω is the angular frequency of the terahertz wave, j is the imaginary operator, ω pe is the angular frequency of the plasma; n e is the electron density; e is the electron charge; m e The mass of the electron.

[0095] In one embodiment of the present invention, the Maxwell equations are:

[0096]

[0097] In the formula, ε p is the equivalent dielectric constant, j is an imaginary operator, ω is the angular frequency of the terahertz wave, is the magnetic field intensity vector, is the electric field strength vector.

[0098] In one embodiment of the present invention, when the plasma is in a low temperature state, the electric field distribution is determined by the following formula:

[0099]

[0100] In the formula, μ r is the relative magnetic permeability of the plasma, ε r is the relative dielectric constant, ε0 is the vacuum dielectric constant, ω is the angular frequency of the terahertz wave, j is the operator of the imaginary number, ω pe is the angular frequency of the plasma, σ is the conductivity, is the electric field vector.

[0101] In one embodiment of the present invention, when the plasma is in a high temperature state, the electric field distribution is determined by the following formula:

[0102]

[0103] In the formula, μ r is the relative magnetic permeability of the plasma, ε r is the relative dielectric constant, ε0 is the vacuum dielectric constant, ν is the collision frequency, ω is the angular frequency of the terahertz wave, j is the imaginary operator, ω pe is the angular frequency of the plasma, σ is the conductivity, is the electric field vector.

[0104] In one embodiment of the present invention, the conductivity of the plasma is zero.

[0105] It is to be understood that the structure illustrated in the embodiment of the present invention does not constitute a specific limitation on a device for simulating the transmission characteristics of a plasma-covered flat plate terahertz wave. In other embodiments of the present invention, a device for simulating the transmission characteristics of a plasma-covered flat plate terahertz wave may include more or fewer components than shown in the figure, or combine some components, or split some components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0106] The information interaction, execution process and other contents between the modules in the above-mentioned device are based on the same concept as the embodiment of the method of the present invention. For the specific contents, please refer to the description in the embodiment of the method of the present invention, and no further description is given here.

[0107] An embodiment of the present invention further provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, a simulation method for the terahertz wave transmission characteristics of a plasma-covered flat plate in any embodiment of the present invention is implemented.

[0108] An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the processor executes a method for simulating terahertz wave transmission characteristics of a plasma-covered flat plate in any embodiment of the present invention.

[0109] Specifically, a system or device equipped with a storage medium can be provided, on which software program codes that implement the functions of any of the above-mentioned embodiments are stored, and a computer (or CPU or MPU) of the system or device can be enabled to read and execute the program codes stored in the storage medium.

[0110] In this case, the program code itself read from the storage medium can realize the function of any one of the above-mentioned embodiments, and thus the program code and the storage medium storing the program code constitute a part of the present invention.

[0111] The storage medium embodiments for providing the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, the program code can be downloaded from a server computer by a communication network.

[0112] In addition, it should be clear that the functions of any of the above embodiments can be implemented not only by executing the program code read by the computer, but also by enabling an operating system operating on the computer to complete part or all of the actual operations based on instructions from the program code.

[0113] In addition, it can be understood that the program code read from the storage medium is written to a memory provided in an expansion board inserted into the computer or to a memory provided in an expansion module connected to the computer, and then based on the instructions of the program code, a CPU installed on the expansion board or expansion module is enabled to perform part or all of the actual operations, thereby realizing the functions of any of the above-mentioned embodiments.

[0114] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0115] A person of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, etc., various media that can store program codes.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for simulating the transmission characteristics of terahertz waves in a plasma-covered flat plate, characterized in that: include: Acquire geometric parameters of the plasma-covered plate and characteristic parameters of the plasma; wherein the characteristic parameters include the electron density and collision frequency of the plasma; Based on the geometric parameters, a two-dimensional model of the plasma-covered flat plate is determined, and corresponding material properties are assigned to the two-dimensional model to obtain a physical model; wherein the physical model includes a plasma region, a free space region, and a flat plate material region, the free space region, the plasma region, and the flat plate material region are sequentially connected, the free space region is an entrance region and a reflection exit region of the terahertz wave, and the flat plate material region is a transmission exit region of the terahertz wave; Bringing the characteristic parameters into the plasma region to obtain a simulation model of terahertz wave transmission characteristics of a plasma-covered flat plate; Finite element simulation calculation is performed using the simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate to obtain the electric field distribution of the terahertz wave after passing through the plasma-covered flat plate; wherein the electric field distribution includes the electric fields in different directions of the incident port and the electric field of the exit port; Determining the terahertz wave transmission characteristics of the plasma covered slab based on the electric fields in different directions of the incident port and the electric field of the exit port; The transmission characteristics of the terahertz wave are obtained based on the comparison of the electric fields in the same direction between the incident port and the output port, and the reflection characteristics of the terahertz wave are obtained based on the comparison of the electric fields in different directions of the incident port. Based on setting the left and right sides of the two-dimensional model as periodic boundaries, the extended plasma layer and the flat plate layer are infinitely long in the lateral direction; Based on setting the terahertz wave to be incident on the plasma-covered plate at different incident angles, the oblique incidence reflection characteristics and transmission characteristics when the terahertz wave is incident on the plasma-covered plate at different angles are obtained.

2. The method according to claim 1, characterized in that The method of using the simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate to perform simulation calculations to obtain the electric field distribution of the terahertz wave after passing through the plasma-covered flat plate includes: Based on the characteristic parameters, determining the equivalent dielectric constant of the plasma; Solving Maxwell's equations based on the equivalent dielectric constant; Based on the Maxwell equations, the electric field distribution of the terahertz wave is determined.

3. The method according to claim 2, characterized in that The equivalent dielectric constant is determined by the following formula: In the formula, ε p is the equivalent dielectric constant, ε r is the relative dielectric constant, ε0 is the vacuum dielectric constant, ν is the collision frequency, ω is the angular frequency of the terahertz wave, j is the imaginary operator, ω pe is the angular frequency of the plasma; n e is the electron density; e is the electron charge; m e The mass of the electron.

4. The method according to claim 2, characterized in that: The Maxwell equations are: In the formula, ε p is the equivalent dielectric constant, j is an imaginary operator, ω is the angular frequency of the terahertz wave, is the magnetic field intensity vector, is the electric field strength vector.

5. The method according to claim 2, characterized in that: When electromagnetic waves are transmitted in low-temperature plasma, the electric field distribution is determined by the following formula: In the formula, μ r is the relative magnetic permeability of the plasma, ε r is the relative dielectric constant, ε0 is the vacuum dielectric constant, ω is the angular frequency of the terahertz wave, j is the operator of the imaginary number, ω pe is the angular frequency of the plasma, σ is the conductivity, is the electric field vector.

6. The method according to claim 2, characterized in that When electromagnetic waves are transmitted in high-temperature plasma, the electric field distribution is determined by the following formula: In the formula, μ r is the relative magnetic permeability of the plasma, ε r is the relative dielectric constant, ε0 is the vacuum dielectric constant, ν is the collision frequency, ω is the angular frequency of the terahertz wave, j is the imaginary operator, ω pe is the angular frequency of the plasma, σ is the conductivity, is the electric field vector.

7. The method according to any one of claims 2 to 6, characterized in that: The conductivity of the plasma is zero.

8. A device for simulating the transmission characteristics of terahertz waves in a plasma-covered flat plate, characterized in that: include: An acquisition module, used to acquire geometric parameters of the plasma-covered plate and characteristic parameters of the plasma; wherein the characteristic parameters include the electron density and collision frequency of the plasma; A first model building module is used to determine the two-dimensional model of the plasma-covered flat plate based on the geometric parameters, and assign corresponding material properties to the two-dimensional model to obtain a physical model; wherein the physical model includes a plasma region, a free space region and a flat plate material region, the free space region, the plasma region and the flat plate material region are sequentially connected, the free space region is an entrance region and a reflection exit region of the terahertz wave, and the flat plate material region is a transmission exit region of the terahertz wave; A second model building module is used to bring the characteristic parameters into the plasma region to obtain a simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate; A first data processing module is used to perform simulation calculations using a simulation model of the terahertz wave transmission characteristics of the plasma-covered flat plate to obtain an electric field distribution of the plasma-covered flat plate; wherein the electric field distribution includes electric fields in different directions of an incident port and an electric field at an exit port; The second data processing module is used to determine the terahertz wave transmission characteristics of the plasma covered slab based on the electric fields in different directions of the incident port and the electric field of the exit port.

9. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed in a computer, the computer is caused to execute the method according to any one of claims 1 to 7.

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