CN114980466A - Method for realizing electromagnetic wave focusing based on non-uniform plasma structure - Google Patents
Method for realizing electromagnetic wave focusing based on non-uniform plasma structure Download PDFInfo
- Publication number
- CN114980466A CN114980466A CN202210342720.0A CN202210342720A CN114980466A CN 114980466 A CN114980466 A CN 114980466A CN 202210342720 A CN202210342720 A CN 202210342720A CN 114980466 A CN114980466 A CN 114980466A
- Authority
- CN
- China
- Prior art keywords
- plasma
- vacuum chamber
- electromagnetic wave
- driving power
- density
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 33
- 230000001105 regulatory effect Effects 0.000 claims abstract description 30
- 230000001965 increasing effect Effects 0.000 claims abstract description 15
- 239000007789 gas Substances 0.000 claims description 60
- 238000009826 distribution Methods 0.000 claims description 18
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 14
- 238000005315 distribution function Methods 0.000 claims description 9
- 239000001307 helium Substances 0.000 claims description 9
- 229910052734 helium Inorganic materials 0.000 claims description 9
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 9
- 230000033228 biological regulation Effects 0.000 claims description 8
- 229910052786 argon Inorganic materials 0.000 claims description 7
- 210000002381 plasma Anatomy 0.000 abstract description 197
- 230000005540 biological transmission Effects 0.000 abstract description 15
- 230000000694 effects Effects 0.000 description 7
- 230000001902 propagating effect Effects 0.000 description 6
- 239000002245 particle Substances 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 238000005086 pumping Methods 0.000 description 4
- 238000007599 discharging Methods 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 230000005674 electromagnetic induction Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/26—Plasma torches
- H05H1/32—Plasma torches using an arc
- H05H1/34—Details, e.g. electrodes, nozzles
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/46—Generating plasma using applied electromagnetic fields, e.g. high frequency or microwave energy
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Electromagnetism (AREA)
- Plasma Technology (AREA)
Abstract
The invention provides a method for realizing electromagnetic wave focusing based on a non-uniform plasma structure, and relates to the technical field of plasmas. The invention discloses a method for realizing electromagnetic wave focusing based on a non-uniform plasma structure, which comprises the following steps: filling ionized gas into a vacuum chamber, wherein a coaxial grid electrode group and a central regulating electrode are arranged in the vacuum chamber; connecting a first driving power supply to the coaxial grid electrode group, and ionizing the ionized gas through the coaxial grid electrode group to generate plasma; a second driving power supply is connected to the central regulating electrode, and the plasma is attracted through the central regulating electrode so as to generate a non-uniform plasma cylinder with the density gradually increasing from inside to outside; the electromagnetic wave is focused by the non-uniform plasma cylinder. According to the technical scheme, the electromagnetic wave is focused, and the transmission loss is reduced; the application range of the non-uniform plasma cylinder is expanded.
Description
Technical Field
The invention relates to the technical field of plasmas, in particular to a method for realizing electromagnetic wave focusing based on a non-uniform plasma structure.
Background
At present, wireless energy transmission mainly comprises the following energy transmission modes: electromagnetic induction, electromagnetic resonance and microwave energy transmission. The electromagnetic induction is suitable for high-power energy transmission, but the working frequency is low, and the transmission distance is very close; electromagnetic resonance is suitable for energy transmission at moderate powers and transmission distances, but it typically operates at frequencies from kilohertz to megahertz. Compared with other two modes, the microwave energy transmission is suitable for the energy transmission with small power or large power from a near field to a far field distance, and the advantages are more obvious. However, based on the classical electromagnetic theory, when the electromagnetic wave propagates in space, a diffraction phenomenon occurs, and energy is diffused in space, so that the energy transmission efficiency of the electromagnetic wave is lowered.
Disclosure of Invention
The problem addressed by the present invention is how to enhance the electromagnetic wave focusing effect to reduce transmission loss.
In order to solve the above problems, the present invention provides a method for realizing electromagnetic wave focusing based on a non-uniform plasma structure, comprising: filling ionized gas into a vacuum chamber, wherein a coaxial grid electrode group and a central regulating electrode are arranged in the vacuum chamber; connecting a first driving power supply to the coaxial grid electrode group, and ionizing the ionized gas through the coaxial grid electrode group to generate plasma; connecting a second driving power supply to the central regulating electrode, and attracting the plasma through the central regulating electrode to generate a non-uniform plasma cylinder with the density gradually increasing from inside to outside; the electromagnetic wave is focused by the non-uniform plasma cylinder.
According to the method for realizing the electromagnetic wave focusing based on the non-uniform plasma structure, the non-uniform plasma is generated through the coaxial grid electrode group arranged in the vacuum chamber, and the plasma is attracted through the central regulating electrode, so that a non-uniform plasma cylinder with the density gradually increasing from inside to outside is formed, and the refractive index is gradually reduced from inside to outside along the radial direction, so that the focusing function similar to a convex lens can be realized, the electromagnetic wave focusing is realized, and the transmission loss is reduced; because the density and other parameters of the plasma are flexible and variable, the parameters of the plasma can be changed according to actual conditions to adapt to different application scenes, so that the application range of the non-uniform plasma cylinder is expanded.
Optionally, the charging of the ionized gas in the vacuum chamber comprises: exhausting air in the vacuum chamber from the air exhaust port of the vacuum chamber through a vacuum pump until the air pressure value of the vacuum chamber reaches a first preset air pressure; and filling the ionized gas into the vacuum chamber from the gas filling port of the vacuum chamber until the gas pressure value of the vacuum chamber reaches a second preset gas pressure.
According to the method for realizing the electromagnetic wave focusing based on the non-uniform plasma structure, the ionized gas is filled in the vacuum chamber through the vacuum pump, the air pressure is kept stable, a stable plasma structure is formed, and the electromagnetic wave focusing is further realized.
Optionally, the charging of the ionized gas in the vacuum chamber further comprises: and adjusting the second preset gas pressure to change the density of the plasma.
The method for realizing the electromagnetic wave focusing based on the non-uniform plasma structure adapts to different application scenes by adjusting the second preset air pressure to change the density of the plasma, thereby expanding the application range of the non-uniform plasma cylinder.
Optionally, the coaxial grid electrode group includes a discharge cathode located at an inner side and a discharge anode located at an outer side, the connecting a first driving power source to the coaxial grid electrode group, and the ionizing the ionized gas by the coaxial grid electrode group to generate the plasma includes: connecting the discharge anode to a positive electrode of the first driving power source, and connecting the discharge cathode to a cavity for forming the vacuum chamber; generating the plasma between the discharge cathode and the discharge anode when the first driving power source is operated, wherein the plasma is adapted to diffuse within the vacuum chamber through a mesh on the discharge cathode.
The method for realizing the electromagnetic wave focusing based on the non-uniform plasma structure generates the non-uniform plasma through the coaxial grid electrode group consisting of the discharge cathode and the discharge anode, and the plasma is diffused into the vacuum chamber through the grids on the cathode electrode, thereby forming the non-uniform plasma.
Optionally, said switching a first driving power into said set of coaxial grid electrodes, said ionizing said ionized gas by said set of coaxial grid electrodes to generate a plasma further comprises: adjusting a voltage between the discharge cathode and the discharge anode by the first driving power source to change a density of the plasma.
The method for realizing the electromagnetic wave focusing based on the non-uniform plasma structure adjusts the voltage between the discharge cathode and the discharge anode through the first driving power supply to change the density of the plasma, so as to adapt to different application scenes, and further expand the application range of the non-uniform plasma cylinder.
Optionally, the switching a second driving power into the central regulating electrode, and the attracting the plasma through the central regulating electrode includes: connecting the central regulation electrode to a positive electrode of the second driving power source, and drawing the plasma to the center of the vacuum chamber through the central regulation electrode.
According to the method for realizing the electromagnetic wave focusing based on the non-uniform plasma structure, the plasma is attracted to the center of the vacuum chamber through the center regulating electrode, so that a non-uniform plasma cylinder with the density gradually increasing from inside to outside is formed, and the electromagnetic wave focusing is realized.
Optionally, the switching a second driving power into the central regulating electrode, and attracting the plasma through the central regulating electrode further includes: and adjusting the voltage of the central regulating electrode through the second driving power supply so as to change the density distribution of the plasma.
According to the method for realizing the electromagnetic wave focusing based on the non-uniform plasma structure, the voltage of the central regulation electrode is adjusted through the second driving power supply so as to change the density distribution of the plasma, and therefore different electromagnetic wave focusing effects are realized.
Optionally, the refractive index of the non-uniform plasma cylinder is determined by a first formula, the first formula comprising:
wherein N represents the refractive index, ε represents the dielectric constant of the plasma, ε 0 Represents the dielectric constant of the vacuum, ω represents the frequency of the electromagnetic wave, ω pe Representing the frequency of the plasma, e representing the electron charge, m e Representing the electron mass, and n representing the density of the plasma.
The method for realizing the electromagnetic wave focusing based on the non-uniform plasma structure determines the refractive index of the non-uniform plasma cylinder which is gradually reduced from inside to outside through a first formula, and realizes the electromagnetic wave focusing.
Optionally, the density distribution function of the non-uniform plasma cylinder is:
n＝1×10 16 +1.36×10 20 r 2 ；
wherein n represents the density of the plasma and r represents the distance from the center of the circle.
The method for realizing the electromagnetic wave focusing based on the non-uniform plasma structure realizes the focusing of the electromagnetic wave with the frequency range larger than 6.4GHz by setting the density distribution function of the non-uniform plasma cylinder.
Optionally, the ionized gas comprises argon and helium.
According to the method for realizing the electromagnetic wave focusing based on the non-uniform plasma structure, ionized gases including argon and helium are arranged, and different ionized gases can be selected according to actual conditions to generate the non-uniform plasma cylinder so as to focus electromagnetic waves with different frequencies.
Drawings
FIG. 1 is a schematic diagram of a method for achieving electromagnetic wave focusing based on a non-uniform plasma structure according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an apparatus for generating a non-uniform plasma column according to an embodiment of the present invention;
FIG. 3 is a schematic view of a non-uniform plasma cylinder according to an embodiment of the present invention;
FIG. 4 is a cross-sectional view of a non-uniform plasma cylinder in accordance with an embodiment of the present invention;
FIG. 5 is a CST model for simulating a non-uniform plasma column according to an embodiment of the present invention;
FIG. 6 is a graph showing the energy density distribution of a 7GHz electromagnetic wave propagating in a non-uniform plasma cylinder according to an embodiment of the present invention;
FIG. 7 is the energy density distribution of the 10GHz electromagnetic wave propagating in the non-uniform plasma cylinder according to the embodiment of the invention;
FIG. 8 is a graph showing the energy density distribution of a 7GHz electromagnetic wave propagating in a uniform plasma cylinder according to an embodiment of the present invention;
FIG. 9 shows the energy density distribution of a 10GHz electromagnetic wave propagating in a uniform plasma cylinder according to an embodiment of the present invention.
Detailed Description
In order to ensure that the energy of the electromagnetic wave is not diffused when being transmitted in space, the electromagnetic wave must be focused to a receiving device like light. At present, focusing electromagnetic waves mainly starts from two parts, namely, on an emission source, an antenna is designed to generate a non-diffraction electromagnetic wave such as Bessel wave beam, and the wave beam energy of the electromagnetic wave is not diffused in a transmission range; or the focusing antenna is designed to emit an electromagnetic wave with focusing characteristics, so that the beam can be focused when reaching the rectifying antenna. However, since the size of the antenna element must be close to the wavelength of the electromagnetic wave, the antenna array must be enlarged to improve performance, and the physical size and the control circuit size thereof become difficult to control. Secondly, a microwave device such as an electromagnetic wave regulation lens is designed, and the precise control of electromagnetic waves is realized by using a material with high refractive index and changing the thickness of a medium in the normal direction of the lens to achieve different accumulated phase distribution on an incident plane. However, the high refractive index medium tends to have a high density, which leads to a high mass of the electromagnetic wave lens; the wavelength of the microwave band is also larger, so that the thickness of the lens exceeds the practical range to realize enough accumulated phase difference; and the physical properties of the medium determine that conventional lenses cannot flexibly change their performance during use.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
As shown in fig. 1, an embodiment of the present invention provides a method for implementing electromagnetic wave focusing based on a non-uniform plasma structure, including: filling ionized gas into a vacuum chamber, wherein a coaxial grid electrode group and a central regulating electrode are arranged in the vacuum chamber; connecting a first driving power supply to the coaxial grid electrode group, and ionizing the ionized gas through the coaxial grid electrode group to generate plasma; a second driving power supply is connected to the central regulating electrode, and the plasma is attracted through the central regulating electrode so as to generate a non-uniform plasma cylinder with the density gradually increasing from inside to outside; the electromagnetic wave is focused by the non-uniform plasma cylinder.
Specifically, in this embodiment, with reference to fig. 2, a method for achieving electromagnetic wave focusing based on a non-uniform plasma structure includes: the method comprises the steps of filling ionized gas into a sealed cylindrical vacuum chamber, connecting a first driving power supply (such as a high-voltage power supply of 300V-1200V) into a coaxial grid electrode group arranged in the vacuum chamber, ionizing the ionized gas in the coaxial grid electrode group to generate a large amount of plasma, diffusing the plasma into the whole vacuum chamber through grids of the electrodes, forming non-uniform plasma with the density gradually reduced from outside to inside due to the fact that the plasma is diffused from outside to inside, connecting a second driving power supply into a central regulating electrode, sucking the plasma through the central regulating electrode to form a non-uniform plasma cylinder (with the axis of the cylinder as the inside and the edge of the cylinder as the outside) with the density gradually increased from inside to outside as shown in figures 3 and 4, and further focusing electromagnetic waves through the non-uniform plasma cylinder.
Plasma is a multi-particle system composed of charged particles (positive ions, negative ions, and electrons) and various neutral particles (atoms, molecules, radicals, and reactive groups). When various currents and particle beams exist within the plasma, the propagation of waves within the plasma becomes extremely complicated. When a particle beam is present, electromagnetic waves may not only be attenuated, but also amplified when propagating in the plasma. Plasma is a dispersive medium whose relative dielectric constant varies with frequency and density and can be described by Drude model. In addition, the plasma has very light weight, and the performance of the plasma can be changed by flexibly changing parameters such as plasma density and the like so as to adapt to different scenes, so that the plasma has certain advantages.
As shown in fig. 5, the cstudiosuite software was used to simulate the propagation of electromagnetic waves in the above-mentioned non-uniform plasma cylinder, thereby demonstrating the feasibility of the method of focusing electromagnetic waves using the complex plasma structure formed by the non-uniform plasma. A plurality of layers of rings with the same thickness and different inner diameters form a cylinder, each layer of ring is provided with different plasma densities, and the plasma densities gradually increase from inside to outside to simulate non-uniform plasma. The boundary condition is set as an open (open) condition, that is, the electromagnetic wave is absorbed when being transmitted to the boundary of the model, which is equivalent to being transmitted to infinity, and corresponds to an open environment when the wireless microwave energy is actually transmitted. The port uses plane wave of quasi-TEM mode, and propagates along the central axis direction of the column body, and a Field monitor (Field Monitors) for electromagnetic wave energy density is arranged, so as to obtain the energy distribution of the electromagnetic wave in the plasma column to observe whether focusing is carried out or not.
According to the formula of the dielectric constant of electromagnetic waves propagating in plasma:
wherein epsilon and epsilon 0 Dielectric constants in plasma and vacuum, ω and ω, respectively pe Respectively, the frequencies of the electromagnetic wave and the plasma, n is the plasma electron density, e and m e Is the charge and mass of the electron.
According to a dielectric constant formula, the dielectric constant of the distributed plasma is gradually reduced from inside to outside, and the refractive index formula is as follows:
it can be seen that the refractive index also decreases gradually from the inside to the outside in the radial direction. The refractive index of the distribution is similar to the working principle of a convex lens, and the phase of the edge electromagnetic wave is larger than that of the central electromagnetic wave. Therefore, when the electromagnetic wave is transmitted inside, the distributed plasma is similar to a convex lens, and the electromagnetic wave is focused. The focusing effect is related to the gradient of the plasma density increasing from inside to outside, the larger the gradient increasing from inside to outside is, the focal length of the convex lens is reduced, and the faster the electromagnetic wave is focused, the energy lost in the midway is reduced.
For example, the non-uniform plasma cylinder has a radius of 60mm (0.06m), a length of 400mm (0.4m), and a plasma density of 1X 10 from the center 16 m -3 To the outermost 5X 10 17 m -3 The density distribution function is:
n＝1×10 16 +1.36×10 20 r 2 ；
since the electromagnetic wave frequency omega must be greater than the plasma frequency omega pe The frequency point is the cutoff frequency below which the dielectric constant is negative and electromagnetic waves cannot propagate, and the plasma frequency is maximum:
therefore, the frequency range of the electromagnetic wave suitable for the non-uniform plasma column with the density distribution is larger than 6.4 GHz.
And simulating the propagation of electromagnetic waves in the non-uniform plasma cylinder by using CSTSUDIOSUITE software, wherein the thickness of each layer of circular ring is 2mm, the number of the layers is 30, the density of each layer of plasma is set according to a density distribution function, and other settings are the same as the general settings and are not repeated.
Referring to fig. 6 and 7, the frequencies of the electromagnetic waves are 7GHz and 10GHz, respectively, and it can be seen that the energy is high at the center and is concentrated in the region near the center axis. The very low energy at the boundary, and the very little energy diffused to the cylinder boundary, confirm that this kind of distributed plasma has realized the focus of electromagnetic energy.
As a control group, electromagnetic waves were simulated at a density of 1X 10 by the same method 17 m -3 Was propagated in the column formed by the uniform plasma to demonstrate that the above effect is produced by the complex plasma structure formed by the non-uniform plasma.
Referring to fig. 8 and 9, the incident wave frequency is 7GHz and 10GHz, and it can be seen that the energy of the whole cylinder is low, and the energy distribution in the uniform plasma is relatively uniform compared to the non-uniform plasma. It is shown that the energy is not focused, most of the energy is diffused to the outside of the column, and the energy transmitted to the tail end of the column is little.
In fig. 6 to 9, comments such as frequency are described in the CSTSTUDIOSUITE software, and are not described herein again.
In the embodiment, the non-uniform plasma is generated by the coaxial grid electrode group arranged in the vacuum chamber, and the plasma is attracted by the central regulating electrode, so that a non-uniform plasma cylinder with the density gradually increasing from inside to outside is formed, and the refractive index is gradually reduced from inside to outside along the radial direction, so that the focusing function similar to a convex lens can be realized, the electromagnetic wave is focused, and the transmission loss is reduced; because the density and other parameters of the plasma are flexible and variable, the parameters of the plasma can be changed according to actual conditions to adapt to different application scenes, so that the application range of the non-uniform plasma cylinder is expanded.
Optionally, the charging of the ionized gas in the vacuum chamber comprises: exhausting air in the vacuum chamber from the air exhaust port of the vacuum chamber through a vacuum pump until the air pressure value of the vacuum chamber reaches a first preset air pressure; and filling the ionized gas into the vacuum chamber from the gas filling port of the vacuum chamber until the gas pressure value of the vacuum chamber reaches a second preset gas pressure.
Specifically, in this embodiment, the pressure in the vacuum chamber is controlled by a vacuum pump, and the vacuum pump is connected to an electromagnetic valve to control the direction of gas evacuation, thereby preventing gas backflow when the vacuum pump is stopped. Usually, the air in the cavity is pumped away from the air pumping port through the vacuum pump until the air pressure value of the vacuum cavity reaches a first preset air pressure, and the air pumping is stopped, so as to ensure the purity of the helium gas. Then, the vacuum chamber is filled with ionized gas, such as helium gas, from the filling port of the vacuum chamber until the pressure value of the vacuum chamber reaches a second preset pressure.
The vacuum chamber is typically coupled to an air pressure sensor for displaying the pressure value in real time in order to control the operating air pressure range of the vacuum pump. The air pumping system and the air charging system work alternately to ensure the stability of the air pressure in the chamber, if the air pressure value exceeds the preset air pressure value, the air pumping system works, otherwise, the air charging system works.
In the embodiment, the vacuum chamber is filled with ionized gas through the vacuum pump, and the pressure is kept stable, so that a stable plasma structure is formed, and the electromagnetic wave focusing is further realized.
Optionally, the charging of the ionized gas in the vacuum chamber further comprises: and adjusting the second preset gas pressure to change the density of the plasma.
Specifically, in the present embodiment, since the higher the gas pressure value of the ionized gas is, the more plasma is generated by its ionization, the higher the plasma density is. The plasma density can thus be adjusted by adjusting the gas pressure value, i.e. changing the second preset gas pressure, with a consequent change in the amount of ionized gas. For example, when the frequency of the electromagnetic wave is lower than the cut-off frequency of the plasma, the cut-off frequency can be adjusted downward by reducing the pressure value of the charged ionized gas, so that the purpose of focusing the low-frequency electromagnetic wave is achieved.
In the embodiment, the density of the plasma is changed by adjusting the second preset air pressure to adapt to different application scenes, so that the application range of the non-uniform plasma cylinder is expanded.
Optionally, the coaxial grid electrode group includes a discharge cathode located at an inner side and a discharge anode located at an outer side, the connecting a first driving power source to the coaxial grid electrode group, and the ionizing the ionized gas by the coaxial grid electrode group to generate the plasma includes: connecting the discharge anode to a positive electrode of the first driving power source, and connecting the discharge cathode to a cavity for forming the vacuum chamber; generating the plasma between the discharge cathode and the discharge anode when the first driving power source is operated, wherein the plasma is adapted to diffuse within the vacuum chamber through a mesh on the discharge cathode.
Specifically, in this embodiment, the coaxial grid electrode group includes two coaxial mesh circular electrodes, the electrode spacing is 3cm, one of the electrodes is connected to the stainless steel cavity and serves as a ground electrode, the other electrode is connected to a power supply and serves as a power supply electrode, and in the actual discharging process, the ground electrode and the power supply electrode alternately serve as a discharging cathode and a discharging anode. Referring to fig. 2, the discharge anode is connected to the positive electrode of the first driving power source, the discharge cathode is connected to the cavity for forming the vacuum chamber, i.e. the inner side is the cathode, the outer side is the anode, a large amount of plasma is generated by ionization between the two electrodes, and part of the plasma is diffused into the whole chamber through the mesh on the cathode electrode.
Wherein, the discharge cathode and the discharge anode which are used as the coaxial grid electrodes are uniformly distributed with 60 multiplied by 13 small holes with the diameter of 1cm, which is convenient for the diffusion of plasma.
In this embodiment, the non-uniform plasma is generated by a coaxial grid electrode assembly consisting of a discharge cathode and a discharge anode, and the plasma diffuses into the vacuum chamber through the grid on the cathode electrode, thereby forming a non-uniform plasma.
Optionally, said switching a first driving power into the coaxial grid electrode set, said ionizing the ionized gas by the coaxial grid electrode set to generate plasma further comprises: adjusting a voltage between the discharge cathode and the discharge anode by the first driving power source to change a density of the plasma.
Specifically, in the present embodiment, since the higher the voltage between the discharge cathode and the discharge anode, the better the degree of ionization, the more plasma is generated, and the higher the density thereof. The plasma density can be adjusted by adjusting the voltage of the first driving power source. For example, when the frequency of the electromagnetic wave is lower than the cut-off frequency of the plasma, the plasma density can be reduced by reducing the voltage between the two coaxial grid electrodes, so that the cut-off frequency is adjusted downwards, and the purpose of focusing the low-frequency electromagnetic wave is achieved. Conversely, for high frequency electromagnetic waves, the cut-off frequency can be adjusted upward by appropriately increasing the plasma density.
In the embodiment, the first driving power supply is used for adjusting the voltage between the discharge cathode and the discharge anode to change the density of the plasma, so that different application scenes are adapted, and the application range of the non-uniform plasma cylinder is expanded.
Optionally, the switching a second driving power into the central regulating electrode, and the attracting the plasma through the central regulating electrode includes: connecting the central regulation electrode to a positive electrode of the second driving power source, and drawing the plasma to the center of the vacuum chamber through the central regulation electrode.
Specifically, in the present embodiment, as shown in fig. 2, the central control electrode is connected to the positive electrode of the second driving power source, and the plasma is attracted to the center of the vacuum chamber through the central control electrode. Because the plasma automatically diffuses into the vacuum chamber, and the plasma is an ionized gaseous substance consisting of positive and negative ions generated after atoms and atomic groups are ionized after part of electrons are deprived, the motion of the plasma is mainly governed by electromagnetic force, and the plasma is attracted by the central control electrode to move towards the center of the vacuum chamber, so that a non-uniform plasma cylinder with the density gradually increasing from inside to outside is formed.
In this embodiment, the plasma is attracted to the center of the vacuum chamber through the center regulating electrode, so that a non-uniform plasma cylinder with gradually increasing density from inside to outside is formed, and the focusing of electromagnetic waves is further realized.
Optionally, the switching a second driving power into the central regulating electrode, and attracting the plasma through the central regulating electrode further includes: and adjusting the voltage of the central regulating electrode through the second driving power supply so as to change the density distribution of the plasma.
Specifically, in this embodiment, since the higher the voltage of the second driving power supply, the more the plasma attracted to the center, the gradient in which the plasma density in the chamber increases from inside to outside decreases, and therefore, the density distribution of the plasma in the chamber can be changed by adjusting the voltage of the center regulating electrode. Because the non-uniform plasma cylinder is similar to a convex lens, the focusing effect is related to the gradient of the plasma density increasing from inside to outside, the larger the gradient increasing from inside to outside is, the focal length of the convex lens is reduced, and the faster the electromagnetic wave is focused, the energy lost in the midway can be reduced.
For example, to reduce the loss of electromagnetic wave energy, the voltage on the center adjustment electrode can be properly reduced to reduce the plasma attracted to the center, or even adjusted to a negative voltage to repel the plasma running to the center due to diffusion, so as to increase the gradient of the plasma from inside to outside, thereby enhancing the focusing effect and reducing the loss.
In this embodiment, the voltage of the central control electrode is adjusted by the second driving power supply to change the density distribution of the plasma, thereby achieving different electromagnetic wave focusing effects.
Optionally, the refractive index of the non-uniform plasma cylinder is determined by a first formula, the first formula comprising:
wherein N represents the refractive index, ε represents the dielectric constant of the plasma, ε 0 Represents the dielectric constant of the vacuum, ω represents the frequency of the electromagnetic wave, ω pe Representing the frequency of the plasma, e representing the electron charge，m e Representing the electron mass, and n representing the density of the plasma.
Specifically, in this embodiment, since the density of the non-uniform plasma cylinder gradually increases from inside to outside, the frequency of the corresponding plasma gradually increases from inside to outside, the dielectric constant of the corresponding plasma gradually decreases from inside to outside, and the corresponding refractive index gradually decreases from inside to outside. The refractive index of the distribution is similar to the working principle of a convex lens, and the phase of the edge electromagnetic wave is larger than that of the central electromagnetic wave. Therefore, when the electromagnetic wave is transmitted inside, the distributed plasma is similar to a convex lens, and the electromagnetic wave is focused.
In the embodiment, the refractive index of the non-uniform plasma cylinder gradually reduced from inside to outside is determined through a first formula, so that the electromagnetic wave is focused.
Optionally, the density distribution function of the non-uniform plasma cylinder is:
n＝1×10 16 +1.36×10 20 r 2 ；
wherein n represents the density of the plasma and r represents the distance from the center of the circle.
Specifically, in the present embodiment, the non-uniform plasma cylinder has a radius of 60mm (0.06m), a length of 400mm (0.4m), and a plasma density of 1X 10 from the center 16 m -3 To the outermost 5X 10 17 m -3 The density distribution function is:
n＝1×10 16 +1.36×10 20 r 2 ；
where n represents the density of the plasma and r represents the distance from the center of the circle (the unit is m).
The non-uniform plasma cylinders with different density distributions have different plasma frequencies, and the maximum value of the plasma density is 5 x 10 of the outermost layer by taking the density distribution function as an example 17 m -3 And the maximum plasma frequency is 6.4GHz, the frequency range of the applicable electromagnetic wave is more than 6.4 GHz. In order to meet the requirements of focusing electromagnetic waves with different frequencies, the density of the non-uniform plasma can be changed according to actual conditionsAnd (4) distribution to realize focusing of high-frequency or low-frequency electromagnetic waves.
In the present embodiment, by setting the density distribution function of the non-uniform plasma cylinder, focusing of electromagnetic waves in a frequency range greater than 6.4GHz is achieved.
Optionally, the ionized gas comprises argon and helium.
Specifically, in this embodiment, the vacuum chamber is typically provided with an observation window through which the plasma can be seen to emit a uniform violet light when ionizing argon gas, and a uniform white light source when ionizing helium gas, as determined by the characteristic lines of argon and helium gas.
Since plasma density can be influenced by different ionized gases, different ionized gases can be selected according to actual conditions to generate a non-uniform plasma cylinder so as to focus electromagnetic waves with different frequencies.
In the embodiment, by setting the ionized gases to include argon and helium, different ionized gases can be selected according to actual conditions to generate the non-uniform plasma cylinder so as to focus electromagnetic waves with different frequencies.
Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present disclosure, and these changes and modifications are intended to be within the scope of the present disclosure.
Claims (10)
1. A method for realizing electromagnetic wave focusing based on a non-uniform plasma structure is characterized by comprising the following steps:
filling ionized gas into a vacuum chamber, wherein a coaxial grid electrode group and a central regulating electrode are arranged in the vacuum chamber;
connecting a first driving power supply to the coaxial grid electrode group, and ionizing the ionized gas through the coaxial grid electrode group to generate plasma;
connecting a second driving power supply to the central regulating electrode, and attracting the plasma through the central regulating electrode to generate a non-uniform plasma cylinder with the density gradually increasing from inside to outside;
the electromagnetic wave is focused by the non-uniform plasma cylinder.
2. The method of claim 1, wherein the filling of the ionized gas into the vacuum chamber comprises:
exhausting air in the vacuum chamber from the air exhaust port of the vacuum chamber through a vacuum pump until the air pressure value of the vacuum chamber reaches a first preset air pressure;
and filling the ionized gas into the vacuum chamber from the gas filling port of the vacuum chamber until the gas pressure value of the vacuum chamber reaches a second preset gas pressure.
3. The method of claim 2, wherein the filling of the ionized gas in the vacuum chamber further comprises:
and adjusting the second preset gas pressure to change the density of the plasma.
4. The method of claim 1, wherein the coaxial grid electrode group comprises a discharge cathode at an inner side and a discharge anode at an outer side, the connecting a first driving power source to the coaxial grid electrode group, and the ionizing the ionized gas by the coaxial grid electrode group to generate the plasma comprises:
connecting the discharge anode to a positive electrode of the first driving power source, and connecting the discharge cathode to a cavity for forming the vacuum chamber;
generating the plasma between the discharge cathode and the discharge anode when the first driving power source is operated, wherein the plasma is adapted to diffuse within the vacuum chamber through a mesh on the discharge cathode.
5. The method of claim 4, wherein the switching a first driving power into the set of coaxial grid electrodes, and the ionizing the ionized gas by the set of coaxial grid electrodes to generate the plasma further comprises:
adjusting a voltage between the discharge cathode and the discharge anode by the first driving power source to change a density of the plasma.
6. The method as claimed in claim 4, wherein the step of connecting a second driving power to the central control electrode, and the step of attracting the plasma through the central control electrode comprises:
connecting the central regulation electrode to a positive electrode of the second driving power source, and drawing the plasma to the center of the vacuum chamber through the central regulation electrode.
7. The method as claimed in claim 6, wherein the step of connecting a second driving power to the central control electrode, and attracting the plasma via the central control electrode further comprises:
and adjusting the voltage of the central regulating electrode through the second driving power supply so as to change the density distribution of the plasma.
8. The method of claim 1, wherein the refractive index of the non-uniform plasma cylinder is determined by a first formula, the first formula comprising:
wherein N represents the foldThe refractive index, ε, represents the dielectric constant, ε, of the plasma 0 Represents the dielectric constant of the vacuum, ω represents the frequency of the electromagnetic wave, ω pe Representing the frequency of the plasma, e representing the electron charge, m e Representing the electron mass, and n representing the density of the plasma.
9. The method of claim 8, wherein the non-uniform plasma cylinder has a density distribution function as follows:
n＝1×10 16 +1.36×10 20 r 2 ；
wherein n represents the density of the plasma, and r represents the distance from the center of the circle.
10. A method for realizing electromagnetic wave focusing based on a non-uniform plasma structure as claimed in any one of claims 1 to 9, wherein the ionized gas includes argon and helium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210342720.0A CN114980466A (en) | 2022-04-02 | 2022-04-02 | Method for realizing electromagnetic wave focusing based on non-uniform plasma structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210342720.0A CN114980466A (en) | 2022-04-02 | 2022-04-02 | Method for realizing electromagnetic wave focusing based on non-uniform plasma structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114980466A true CN114980466A (en) | 2022-08-30 |
Family
ID=82977698
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210342720.0A Pending CN114980466A (en) | 2022-04-02 | 2022-04-02 | Method for realizing electromagnetic wave focusing based on non-uniform plasma structure |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114980466A (en) |
Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB706722A (en) * | 1950-09-20 | 1954-04-07 | Rca Corp | Improvements relating to gas filled electric discharge devices |
| US6172324B1 (en) * | 1997-04-28 | 2001-01-09 | Science Research Laboratory, Inc. | Plasma focus radiation source |
| KR20020035249A (en) * | 2000-11-06 | 2002-05-11 | 장홍영 | Device and Method for Generating Capacitively Coupled Plasma Enhanced Inductively Coupled Plasma |
| US6431114B1 (en) * | 1998-09-30 | 2002-08-13 | Tokyo Electron Limited | Method and apparatus for plasma processing |
| CN101242702A (en) * | 2007-01-30 | 2008-08-13 | 应用材料股份有限公司 | Plasma reactor with ion distribution uniformity controller employing plural VHF sources |
| CN106415779A (en) * | 2013-12-17 | 2017-02-15 | 东京毅力科创株式会社 | System and method for controlling plasma density |
| CN107491580A (en) * | 2017-06-30 | 2017-12-19 | 西安电子科技大学 | High-speed aircraft plasma sheath radial direction time-varying electron density analogy method |
| CN107644140A (en) * | 2017-10-11 | 2018-01-30 | 上海无线电设备研究所 | A kind of plasma material design method |
| CN107958105A (en) * | 2017-11-09 | 2018-04-24 | 上海无线电设备研究所 | A kind of method reflected using plasma-coated reduction electromagnetic wave in metal surface |
| CN107979910A (en) * | 2017-11-29 | 2018-05-01 | 中国人民解放军陆军工程大学 | Dielectric material surface potential Active Control Method under high vacuum environment |
| US20190074165A1 (en) * | 2017-09-01 | 2019-03-07 | Samsung Electronics Co., Ltd. | Plasma processing apparatus and method of manufacturing semiconductor device using the same |
| CN109545643A (en) * | 2018-11-19 | 2019-03-29 | 国网四川省电力公司电力科学研究院 | A kind of large volume honeycomb corona plasma 3D uniformity regulating device |
| CN109640501A (en) * | 2018-11-20 | 2019-04-16 | 上海无线电设备研究所 | A kind of diagnostic system and method for inhomogeneous plasma electron density |
| CN114071849A (en) * | 2021-11-15 | 2022-02-18 | 上海无线电设备研究所 | Plasma generator for hypersonic target ablation diffusion object |
| RU2792344C1 (en) * | 2022-11-16 | 2023-03-21 | Общество с ограниченной ответственностью "НПП ЛМ Инвестор" | Gas-discharge electron gun controlled by an ion source with closed electron drift |
-
2022
- 2022-04-02 CN CN202210342720.0A patent/CN114980466A/en active Pending
Patent Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB706722A (en) * | 1950-09-20 | 1954-04-07 | Rca Corp | Improvements relating to gas filled electric discharge devices |
| US6172324B1 (en) * | 1997-04-28 | 2001-01-09 | Science Research Laboratory, Inc. | Plasma focus radiation source |
| US6431114B1 (en) * | 1998-09-30 | 2002-08-13 | Tokyo Electron Limited | Method and apparatus for plasma processing |
| KR20020035249A (en) * | 2000-11-06 | 2002-05-11 | 장홍영 | Device and Method for Generating Capacitively Coupled Plasma Enhanced Inductively Coupled Plasma |
| CN101242702A (en) * | 2007-01-30 | 2008-08-13 | 应用材料股份有限公司 | Plasma reactor with ion distribution uniformity controller employing plural VHF sources |
| CN106415779A (en) * | 2013-12-17 | 2017-02-15 | 东京毅力科创株式会社 | System and method for controlling plasma density |
| CN107491580A (en) * | 2017-06-30 | 2017-12-19 | 西安电子科技大学 | High-speed aircraft plasma sheath radial direction time-varying electron density analogy method |
| US20190074165A1 (en) * | 2017-09-01 | 2019-03-07 | Samsung Electronics Co., Ltd. | Plasma processing apparatus and method of manufacturing semiconductor device using the same |
| CN107644140A (en) * | 2017-10-11 | 2018-01-30 | 上海无线电设备研究所 | A kind of plasma material design method |
| CN107958105A (en) * | 2017-11-09 | 2018-04-24 | 上海无线电设备研究所 | A kind of method reflected using plasma-coated reduction electromagnetic wave in metal surface |
| CN107979910A (en) * | 2017-11-29 | 2018-05-01 | 中国人民解放军陆军工程大学 | Dielectric material surface potential Active Control Method under high vacuum environment |
| CN109545643A (en) * | 2018-11-19 | 2019-03-29 | 国网四川省电力公司电力科学研究院 | A kind of large volume honeycomb corona plasma 3D uniformity regulating device |
| CN109640501A (en) * | 2018-11-20 | 2019-04-16 | 上海无线电设备研究所 | A kind of diagnostic system and method for inhomogeneous plasma electron density |
| CN114071849A (en) * | 2021-11-15 | 2022-02-18 | 上海无线电设备研究所 | Plasma generator for hypersonic target ablation diffusion object |
| RU2792344C1 (en) * | 2022-11-16 | 2023-03-21 | Общество с ограниченной ответственностью "НПП ЛМ Инвестор" | Gas-discharge electron gun controlled by an ion source with closed electron drift |
Non-Patent Citations (3)
| Title |
|---|
| 唐明;胡建生;左桂忠;真空科学及壁处理组;: "HT-7托卡马克中破裂等离子体放电对器壁放气的影响", 真空科学与技术学报, no. 01, 15 January 2011 (2011-01-15), pages 19 * |
| 夏新仁;尹成友;金贤龙;王守杰;: "任意角入射到非均匀等离子体的WKB法", 上海航天, no. 03, 25 June 2009 (2009-06-25) * |
| 姚静锋: "气体放电低温等离子体非局域模型及其应用", 《万方》, 2 December 2021 (2021-12-02), pages 45 - 46 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6512333B2 (en) | RF-powered plasma accelerator/homogenizer | |
| US6803585B2 (en) | Electron-cyclotron resonance type ion beam source for ion implanter | |
| CN104362060A (en) | Dielectric filled compact type relativistic backward wave oscillator | |
| Maxson et al. | Design, conditioning, and performance of a high voltage, high brightness dc photoelectron gun with variable gap | |
| JP3591642B2 (en) | Plasma processing equipment | |
| US5899666A (en) | Ion drag vacuum pump | |
| CN114980466A (en) | Method for realizing electromagnetic wave focusing based on non-uniform plasma structure | |
| CN102312210A (en) | Plasma immersion ion injection system | |
| US5159241A (en) | Single body relativistic magnetron | |
| JP5544598B2 (en) | Photocathode high-frequency electron gun and electron beam apparatus provided with photocathode high-frequency electron gun | |
| CN103606505A (en) | Cold cathode electronic gun modulated by microwave | |
| Zhang et al. | S-band klystron with 300 MHz bandwidth at 850 kW peak power and 20 kW average power | |
| Lawson et al. | Reflections on the university of Maryland’s program investigating gyro-amplifiers as potential sources for linear colliders | |
| McAndrew et al. | Supersonic vehicle control by microwave driven plasma discharges | |
| Sawert et al. | Modelling and Optimisation of a Relativistic Magnetron with Transparent Cathode and TE11 Output Mode | |
| US3944946A (en) | Coherent generation of microwaves by stimulated Raman emissions | |
| CN106898861A (en) | A kind of plasma antenna for working in Terahertz frequency range | |
| RU2267830C1 (en) | Sealed off electron gun for taking band electron flow from vacuum area of gun to atmosphere or other gaseous environment | |
| JP2004152702A (en) | Microwave ion source | |
| CN219738906U (en) | Device for exciting electromagnetic wave by utilizing plasma | |
| CN111510242B (en) | Plasma broadband electromagnetic radiation interference device for enemy plane signal interference | |
| RU2695819C1 (en) | Source of intense flows of low-temperature plasma with high degree of ionisation | |
| US20220087000A1 (en) | Ionic Threading Apparatus | |
| CN117691437A (en) | Terahertz radiation source of electron beam-plasma system based on adjustable grating | |
| Eppley | Design of a 100 MW X-band klystron |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |