Structure, method and vehicle for breaking the black barrier of plasma communication

Abstract

The application provides a structure, a method and a spacecraft for breaking through a plasma communication black barrier, the structure comprising dielectric columns, a plurality of the dielectric columns forming a dielectric column array to form a lattice structure, and the dielectric column array being arranged in a plasma. The structure for breaking through the plasma communication black barrier is simple, the breaking through of the plasma communication black barrier is easy to realize, large energy consumption is not needed, and a signal distortion problem caused by interference does not exist, so that the structure has a good application prospect in the field of aerospace.

Description

Technical Field

[0001] This invention relates to the field of aerospace technology, and more specifically, to a structure, method, and aircraft for overcoming the blackout of plasma communication. Background Technology

[0002] When a spacecraft re-enters the atmosphere, the friction between the spacecraft wall and the surrounding air generates a plasma sheath. This sheath severely attenuates communication signals between the spacecraft and the ground, creating a communication blackout lasting for tens of minutes, which seriously threatens the lives of astronauts. For example, when a spacecraft re-enters the atmosphere at Mach 15, the generated plasma frequency is approximately 1-10 GHz, and the thickness of the plasma sheath is approximately 10 cm. According to the Drude model, when the incident wave frequency is lower than the plasma frequency, the plasma becomes a material with a negative permittivity, causing electromagnetic waves to attenuate as evanescent waves within the plasma sheath.

[0003] The communication blackout problem has long plagued the aerospace industry. Current solutions primarily focus on reducing plasma frequency and increasing incident wave frequency. Examples include spraying electrophilic materials around the spacecraft to reduce electron density, adding magnetic windows to lower electron density around antennas, or using terahertz waves for signal transmission. However, these intuitive physical methods are difficult to implement in practice. For instance, applying a strong magnetic field generates significant energy consumption, and high-frequency electromagnetic waves are subject to strong interference in deep-space communications, leading to signal distortion. Due to the complexity of the plasma sheath formation and related mechanisms around the spacecraft, neither current theoretical nor ground-based simulations offer a perfect solution to the plasma communication blackout problem. Summary of the Invention

[0004] The problem addressed by this invention is how to provide an easily implementable structure that overcomes the blackout of plasma communication.

[0005] To address at least one of the aforementioned problems, the present invention provides a structure for overcoming the blackout of plasma communication, comprising dielectric pillars, wherein a plurality of the dielectric pillars form a dielectric pillar array to form a lattice structure, and the dielectric pillar array is used to be placed in plasma.

[0006] Preferably, the dielectric column is made of a high dielectric constant material.

[0007] Preferably, the material of the medium column includes one of alumina, zirconium oxide, and polytetrafluoroethylene.

[0008] Preferably, the shape of the medium column includes one of a cylinder, a square prism, and a prismatic prism.

[0009] Preferably, the dielectric column is cylindrical in shape, and the diameter of the dielectric column is 2-10 mm.

[0010] Preferably, the height of the medium column is greater than 50 mm.

[0011] Preferably, the crystal structure includes one of a square crystal structure, a hexagonal crystal structure, and a triangular crystal structure.

[0012] Preferably, the lattice constant of the dielectric pillar array is greater than 10 mm.

[0013] The structure for overcoming the plasma communication blackout provided by this invention comprises a dielectric pillar array consisting of multiple dielectric pillars. A lattice structure is formed between the dielectric pillars. When this lattice-structured dielectric pillar array is placed in plasma, electromagnetic waves can couple and propagate forward between the different dielectric pillars, thereby overcoming the plasma communication blackout. The structure for overcoming the plasma communication blackout provided by this invention is relatively simple, easily achieves the breakthrough, requires minimal energy consumption, and avoids signal distortion caused by interference, thus showing promising application prospects in the aerospace field.

[0014] The present invention also provides an aircraft including the structure described above for overcoming the plasma communication blackout.

[0015] The beneficial effects of the aircraft provided by this invention compared to the prior art are the same as those of the structure that breaks through the plasma communication blackout, and will not be described in detail here.

[0016] The present invention also provides a method for overcoming the plasma communication blackout, which is based on the method for overcoming the plasma communication blackout as described above. The structure for overcoming the plasma communication blackout is placed in plasma to form a plasma photonic crystal, so that electromagnetic waves are coupled to each other and propagate forward in the form of evanescent waves between different dielectric pillars of the structure for overcoming the plasma communication blackout, thereby overcoming the plasma communication blackout.

[0017] The method for overcoming the blackout in plasma communication provided by this invention has the same beneficial effects as the prior art, and will not be described again here. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure that breaks through the plasma communication blackout in an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the unit cell planar structure of the dielectric pillar array in an embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the unit cell planar structure of the dielectric pillar array in Embodiment 2 of the present invention;

[0021] Figure 4This is a schematic diagram of the unit cell planar structure of the dielectric pillar array in Embodiment 3 of the present invention;

[0022] Figure 5 This is a schematic diagram of the unit cell planar structure of the dielectric pillar array in Embodiment 4 of the present invention;

[0023] Figure 6 The energy band diagram of the plasma photonic crystal in Embodiment 1 of the present invention;

[0024] Figure 7 The energy band diagram of the plasma photonic crystal in Embodiment 2 of the present invention;

[0025] Figure 8 The energy band diagram of the plasma photonic crystal in Embodiment 3 of the present invention;

[0026] Figure 9 The energy band diagram of the plasma photonic crystal in Embodiment 4 of the present invention;

[0027] Figure 10 This is a graph showing the trend of electromagnetic wave transmittance within the plasma photonic crystal in Embodiment 1 of the present invention. Detailed Implementation

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below.

[0029] It should be noted that, unless otherwise specified, the features in the embodiments of this invention can be combined with each other. The terms "comprising," "including," "containing," and "having" are non-limiting, meaning that other steps and other components that do not affect the result can be added. The above terms cover the terms "composed of" and "substantially composed of." Unless otherwise specified, materials, equipment, and reagents are commercially available.

[0030] Plasma is a dispersive loss medium, according to the formula When the frequency of the incident electromagnetic wave is lower than the plasma frequency, the relative permittivity of the plasma is negative. In this case, the electromagnetic wave decays exponentially within the plasma, leading to a communication blackout. In the formula, ε... r The relative permittivity of the plasma, Let be the frequency of the plasma, and its expression is: n is the electron density of the plasma, n is the unit charge, ε0 is the relative permittivity in vacuum, and m e Let ω be the electron mass, ω be the angular frequency of the incident electromagnetic wave, and v be the collision frequency between the electron and the neutral particle.

[0031] In the tight-binding model describing electron motion, electrons are primarily bound to the vicinity of atomic cores, exhibiting spatial localization. Isolated atoms are treated as zero-order approximations, while the influence of other atomic potential fields is considered a perturbation. The tight-binding method uses the atomic orbital wavefunction to linearly expand the wavefunction of a known periodic crystal structure, thereby calculating the energy band. Furthermore, the tight-binding method in electronic systems has been applied to photonic systems with periodic structures to solve for the energy band structure of photonic crystals. Based on the tight-binding model, electrons are bound to atomic cores, and their wavefunctions decay in free space, while in photonic crystals, electromagnetic waves can propagate freely in the background medium.

[0032] When a spacecraft re-enters the atmosphere, it generates a plasma sheath. The presence of a plasma cutoff frequency causes electromagnetic waves to attenuate in the plasma as evanescent waves. If a structure similar to that of a photonic crystal in a tight-binding model can be constructed in the plasma, it will help solve the problem of plasma communication blackout.

[0033] This invention provides a structure for overcoming the blackout of plasma communication, comprising dielectric pillars, wherein a plurality of dielectric pillars form a dielectric pillar array to form a lattice structure, and the dielectric pillar array is used to be placed in plasma.

[0034] An array of dielectric pillars forms a lattice structure. When placed in plasma, it forms a photonic crystal similar to that in a tight-binding model. Electromagnetic waves incident on the plasma can couple with each other and propagate forward in the plasma, thus breaking through the plasma communication blackout and solving the problem that electromagnetic waves cannot propagate in the negative background of plasma.

[0035] In other words, the embodiments of the present invention construct a plasma photonic crystal by arranging a dielectric pillar array in the plasma, enabling electromagnetic waves to propagate through the plasma photonic crystal, thus solving the problem of plasma communication blackout.

[0036] Figure 1 The diagram shows a structure that overcomes the blackout barrier in plasma communication, such as... Figure 1 As shown, the gray semi-transparent background is a plasma background, and the array distributed in the plasma background is a dielectric pillar array, with a lattice structure formed between the different dielectric pillars.

[0037] Specifically, electromagnetic waves with frequencies lower than the plasma frequency form evanescent waves after entering the plasma. These evanescent waves couple with each other between different dielectric pillars and propagate forward. The evanescent waves do not attenuate in the plasma photonic crystal formed by the dielectric pillars, thus enabling the effective propagation of electromagnetic waves and breaking through the plasma communication blackout.

[0038] The dielectric pillar is made of a high dielectric constant material.

[0039] It should be noted that high dielectric constant materials refer to materials with a dielectric constant higher than that of SiO2, where the dielectric constant of SiO2 is 3.7.

[0040] For example, the materials of the dielectric column include alumina, zirconium oxide, and polytetrafluoroethylene.

[0041] In semiconductors, atoms are arranged periodically to form a specific crystal lattice structure, and electrons move in a periodic potential field, thus generating energy bands. Similarly, in photonic crystals, the periodic variation of the dielectric constant can also generate photonic bands, while frequencies within the photonic bandgap cannot propagate.

[0042] When the dielectric column is made of a high dielectric constant material, the dielectric constant of the dielectric column is significantly higher than that of the background medium in the plasma. The energy of the electromagnetic wave can be better concentrated on the dielectric column, exhibiting a band effect, which enables the electromagnetic wave to couple with each other between different dielectric columns and propagate forward.

[0043] The shape of the dielectric column does not affect the effectiveness of breaking through the plasma communication blackout. For example, the shape of the dielectric column includes one of the following: cylindrical, square, and prismatic, or it can be other shapes.

[0044] In one embodiment, the dielectric pillar is cylindrical in shape, with a diameter of 2-10 mm. Choosing a diameter of 2-10 mm allows for better matching with the GHz band used in deep space communications, achieving superior performance.

[0045] Accordingly, the lattice constant of the dielectric pillar array is greater than 10 mm, enabling good matching with the GHz band in deep space communications.

[0046] The lattice structure formed by the dielectric pillars in the dielectric pillar array can be any lattice structure. For example, the lattice structure includes one of a square lattice structure, a hexagonal lattice structure, and a triangular lattice structure.

[0047] Depending on actual needs, the structure provided by the embodiments of the present invention for overcoming the black barrier of plasma communication can be used to construct two-dimensional or three-dimensional plasma photonic crystals, thereby enabling electromagnetic waves to propagate in different directions.

[0048] When using a two-dimensional plasma photonic crystal, the dielectric pillars in the dielectric pillar array exhibit a periodic distribution in the horizontal direction. In the vertical direction, the distribution is adjusted according to actual conditions, maximizing the height of the dielectric pillars where possible to improve the horizontal propagation of electromagnetic waves. For example, the height of the dielectric pillars is greater than 50 mm to better achieve the periodic distribution in the horizontal direction and enhance the propagation effect of electromagnetic waves within the dielectric pillar array.

[0049] When it is a three-dimensional plasma photonic crystal, the dielectric pillars in the dielectric pillar array need to be periodically distributed not only in the horizontal direction, but also in the vertical direction, so that electromagnetic waves can propagate in multiple directions.

[0050] It should be noted that electromagnetic waves can break through the black barrier of plasma communication by coordinating parameters such as the dielectric constant of the dielectric pillars, the lattice structure in the dielectric pillar array, and the size of the dielectric pillars.

[0051] For example, the tight-binding method can be used to predict the band structure of a unit cell in a dielectric pillar array when it contains different numbers of lattice points. Figure 2 This is a schematic diagram of one of the unit cell structures of a tetragonal lattice array of dielectric pillars. The unit cell includes 6 lattice points, where t0, t1, and t'0 represent the coupling strength between different dielectric pillars, which is inversely proportional to the distance between the dielectric pillars.

[0052] Based on the calculation method of the tight-binding model, the effective Hamiltonian H containing 6 media columns within the unit cell is calculated using the following formula:

[0053]

[0054] Where t0 = 1 / 2, t'0=1, e ikx and e iky Let x and y represent the phase factors propagating in the x and y directions, respectively, and k be the wave vector.

[0055] Then, by solving the eigenvalue equations This allows us to obtain the eigenvalues ​​of the Hamiltonian mentioned above. Therefore, through calculations using tight-binding theory, we can design a lattice structure that meets our objectives.

[0056] Another embodiment of the present invention provides an aircraft including the structure described above for overcoming the plasma communication blackout.

[0057] The beneficial effects of the aircraft provided in this embodiment of the invention compared to the prior art are the same as those of the structure that breaks through the plasma communication blackout, and will not be described again here.

[0058] Another embodiment of the present invention provides a method for overcoming the plasma communication blackout, which is based on the structure for overcoming the plasma communication blackout as described above. The structure for overcoming the plasma communication blackout is placed in plasma to form a plasma photonic crystal, so that electromagnetic waves are coupled to each other and propagate forward in the form of evanescent waves between different dielectric pillars of the structure for overcoming the plasma communication blackout, thereby overcoming the plasma communication blackout.

[0059] The method for overcoming the blackout of plasma communication provided in this embodiment of the invention has the same beneficial effects as the prior art, and will not be described again here.

[0060] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] Example 1

[0062] In this embodiment, the plasma photonic crystal is constructed with dielectric pillars arranged in a dielectric pillar array. Multiple dielectric pillars form a complex structure with a cubic lattice. The dielectric pillars are made of alumina and are cylindrical in shape, each with a diameter of 4 mm and a relative permittivity of 9.4. Each unit cell contains 6 lattice points and has a lattice constant of 20 mm. The unit cell structure of the plasma photonic crystal in this embodiment is as follows: Figure 2 As shown.

[0063] Example 2

[0064] In this embodiment, the plasma photonic crystal is constructed with dielectric pillars arranged in a dielectric pillar array. Multiple dielectric pillars form a complex structure with a cubic lattice. The dielectric pillars are made of alumina and are cylindrical in shape, each with a diameter of 5 mm, a relative permittivity of 9.4, and a lattice constant of 30 mm. The unit cell structure of the plasma photonic crystal in this embodiment is as follows: Figure 3 As shown.

[0065] Example 3

[0066] In this embodiment, the plasma photonic crystal is constructed with dielectric pillars arranged in a dielectric pillar array. Multiple dielectric pillars form a complex structure with a cubic lattice. The dielectric pillars are made of alumina, are cubic in shape, each with a side length of 4 mm, a relative permittivity of 11, and a lattice constant of 20 mm. The unit cell structure of the plasma photonic crystal in this embodiment is as follows: Figure 4 As shown.

[0067] Example 4

[0068] In this embodiment, the plasma photonic crystal is constructed with dielectric pillars arranged in a dielectric pillar array. Multiple dielectric pillars form a hexagonal lattice structure. The dielectric pillars are made of alumina and are cylindrical in shape, each with a diameter of 6 mm, a relative permittivity of 9.4, and a lattice constant of 30 mm. The unit cell structure of the plasma photonic crystal in this embodiment is as follows: Figure 5 As shown.

[0069] Experimental Example 1

[0070] The energy bands of different plasma photonic crystals in Examples 1-4 were simulated and calculated using COMSOL simulation software.

[0071] Simulation results are as follows Figure 6-9 As shown, the plasma cutoff frequency is 5.84 Hz. Figure 6-9 It can be seen that there are energy bands that can support electromagnetic wave propagation in the plasma cutoff region below 5.84Hz, thus breaking through the plasma communication blackout.

[0072] Experiment Example 2

[0073] The plasma was simulated using a glow discharge plasma generator, and the above results were verified through experiments.

[0074] The specific method is as follows: Two molybdenum metal electrodes, each 120mm long, 100mm wide, and 5mm thick, are placed parallel to each other in a vacuum chamber, with a spacing of 15mm. The chamber is filled with argon gas and maintained at a pressure of 60Pa. Under the drive of a DC power supply, plasma is generated between the two electrodes, with an electron density of 102. 17 m -3 On the order of magnitude. Using a broadband horn antenna to measure the transmittance S21 of electromagnetic waves in plasma, a cutoff phenomenon can be observed at 5.8 GHz. Below this frequency, the transmittance of electromagnetic waves decreases with the increase of discharge current, indicating that the cutoff frequency of plasma is 5.8 GHz.

[0075] The plasma photonic crystal constructed in Example 1 was placed between two molybdenum electrodes, with the dielectric column perpendicular to the molybdenum electrodes (the height of the dielectric column was adjusted according to the spacing between the molybdenum electrodes during the experiment so that the dielectric column array could be placed between the two electrodes). The discharge current was adjusted to 0, 100mA and 180mA, and the transmittance S21 of electromagnetic waves under different frequency conditions was recorded.

[0076] The results are as follows Figure 10 As shown, Figure 10 The horizontal axis represents frequency, and the vertical axis represents the electromagnetic wave transmittance S21. Figure 10 It can be seen that in the range of 3.3-4.4 GHz ( Figure 10(In the gray shaded area), the transmittance of electromagnetic waves does not decrease with the increase of discharge current, which is consistent with the theoretical calculation results. This indicates that the method provided by the embodiments of the present invention can realize the propagation of electromagnetic waves in the plasma cutoff region and break through the plasma communication blackout.

[0077] In summary, simulation calculations of Examples 1-4 demonstrate that, under various lattice structures, lattice constants, and dielectric pillars with different dielectric constants, an energy band can be obtained below the plasma cutoff frequency, enabling electromagnetic wave propagation in the plasma cutoff region. The experimental results are consistent with the simulation calculations, further confirming that the method for overcoming the plasma communication blackout provided by these embodiments can achieve electromagnetic wave propagation in the plasma cutoff region and solve the plasma communication blackout problem.

[0078] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A structure for breaking the black barrier of plasma communication, characterized in that, The structure comprises a plurality of dielectric columns, the plurality of dielectric columns form a dielectric column array, the dielectric column array forms a lattice structure, and the dielectric column array is arranged in a plasma, wherein a plurality of dielectric columns form a complex structure of a square lattice, and each unit cell of the dielectric column array contains six lattice points.

2. The structure of breaking the black barrier of plasma communication according to claim 1, characterized in that, The dielectric column is made of a high dielectric constant material.

3. The structure of breaking the black barrier of plasma communication according to claim 2, characterized in that, The dielectric column is made of one of alumina, zirconia and polytetrafluoroethylene.

4. The structure of breaking the black barrier of plasma communication according to claim 1, characterized in that, The dielectric column has one of a cylindrical shape, a square column shape and a prism shape.

5. The structure of breaking the black barrier of plasma communication according to claim 4, characterized in that, The dielectric column has a cylindrical shape, and a diameter of the dielectric column is 2-10 mm.

6. The structure of breaking the black barrier of plasma communication according to claim 1, wherein, The dielectric column has a height greater than 50 mm.

7. The structure of breaking the black barrier of plasma communication according to claim 1, characterized in that, The lattice structure has one of a square lattice structure, a hexagonal lattice structure and a triangular lattice structure.

8. The structure of breaking the plasma communication black barrier according to claim 7, characterized in that, The lattice constant of the dielectric column array is greater than 10 mm.

9. An aircraft, characterized in that The structure breaks through the black barrier of plasma communication, and the structure comprises the structure of any one of claims 1-8.

10. A method for breaking the plasma communication blackout, implemented based on the structure for breaking the plasma communication blackout according to any one of claims 1-8, characterized in that, The structure is arranged in a plasma to form a plasma photonic crystal, so that electromagnetic waves are coupled and propagated forward between different dielectric columns of the structure in the form of evanescent waves, thereby breaking through the black barrier of plasma communication.

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