阅读说明：本技术 多朗缪尔探针电离层电子密度快速探测方法及应用 (Multi-Langmuir probe ionized layer electron density rapid detection method and application ) 是由 张清和 王进 杜清府 单作林 宿文耀 邢赞扬 周岩 李建泉 于 2021-06-29 设计创作，主要内容包括：本公开涉及等离子体诊断技术领域,具体为多朗缪尔探针电离层电子密度快速探测方法及应用,所述方法包括：将至少两个朗缪尔探针安置在电离层等离子体中,探针上施加的电压为在电子饱和区内不同值,根据探针上采集电流值、探针表面积和施加电压的差值就可以得到电子密度。该方法不依赖于完整的I-V特性曲线和电子温度。针对空间等离子体等快速变化的等离子体探测,大大提高了探测的空间分辨率。(The disclosure relates to the technical field of plasma diagnosis, in particular to a rapid detection method of electron density of an ionized layer of a multi-Langmuir probe and application thereof, wherein the method comprises the following steps: at least two Langmuir probes are arranged in the ionized layer plasma, the voltages applied to the probes are different in an electron saturation region, and the electron density can be obtained according to the difference between the collected current value on the probe, the surface area of the probe and the applied voltage. The method does not rely on a complete I-V characteristic and electron temperature. Aiming at the plasma detection of the rapid change of space plasma, the spatial resolution of the detection is greatly improved.)

1. The method for rapidly detecting the electron density of the ionized layer of the multi-Langmuir probe is characterized by comprising the following steps: at least two Langmuir probes are arranged in the ionized layer plasma, the voltages applied to the probes are different in an electron saturation region, and the electron density can be obtained according to the difference between the collected current value on the probe, the surface area of the probe and the applied voltage.

2. The method for rapidly detecting the electron density of the ionosphere of a multi-langmuir probe as claimed in claim 1, wherein the electron density is obtained by the following calculation formula:

in the formula (4), N_eWhich represents the electron density of the plasma and,is constant, A is the probe surface area, I_PFor one acquisition of current value, V, on the probe_PIs the voltage applied to the probe.

3. The method for rapid ionospheric electron density detection with multiple langmuir probes as claimed in claim 1, wherein said applied voltage is any value above the plasma space potential.

4. The method for rapid ionospheric electron density detection with multiple Langmuir probes as claimed in claim 3, wherein the applied voltage (Vb) should be greater than the plasma space potential (Vp) by 2V or more, i.e. (Vb > Vp + 2V).

5. The method for rapid ionospheric electron density detection with multiple langmuir probes as claimed in claim 1, wherein the method is applied to a plasma with a maxwell velocity profile.

6. The method for rapid ionospheric electron density detection with multiple langmuir probes as claimed in claim 5, wherein the plasma density ranges are: 10⁷-10¹⁵m^-3。

7. The method for rapid ionospheric electron density detection with multiple langmuir probes as claimed in claim 1, wherein the langmuir probes are separated by more than 10 debye length.

8. The method for rapidly detecting the electron density of the ionized layer of the multi-langmuir probe as claimed in claim 1, wherein the electron density of the method takes 1ms under the condition that the electronic system acquisition frequency is 1 kHz.

9. A method of plasma monitoring comprising the method of rapid ionospheric electron density detection with a multi-langmuir probe as claimed in any one of claims 1 to 8.

10. Use of the rapid ionospheric electron density detection method using a multi-langmuir probe according to any one of claims 1 to 8 or the plasma monitoring method according to claim 9 in the fields of energy, material chemical engineering, environmental protection, and defense.

Technical Field

The disclosure relates to the technical field of plasma diagnosis, in particular to a multi-Langmuir probe ionized layer electron density rapid detection method and application.

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

The ionosphere is the region where the earth's atmosphere is partially ionized by solar radiation, is an important ring in the solar energy transmission chain, is an important component of the spatial weather, and is the geospatial region closest to the space physics application level. As a main medium for human radio wave propagation and an important place for aerospace activities, the state change of an ionosphere can directly influence human communication, navigation, remote sensing positioning, aerospace activities and the like. The change of the state of the ionized layer is mainly reflected in the change of physical parameters such as plasma density, temperature and the like. Therefore, ionospheric plasma density and temperature sensing are important.

Langmuir probes have been widely used in ionospheric plasma and laboratory manual plasma diagnostics due to their simple structure and reliable results. The traditional diagnosis method of the Langmuir probe is to immerse a metal electrode in plasma, apply a scanning voltage on the electrode by using a control circuit, simultaneously acquire micro-current signals on the probe to obtain an I-V characteristic curve, and further obtain physical parameters of the plasma by combining a diagnosis theory. The Langmuir probe can measure the electron density (N) of the plasma in situ, whether in a space environment or a laboratory simulated environment_e) Electron temperature (T)_e) And (3) equal characteristic parameters.

When the electron density is obtained by using the traditional diagnostic method, firstly, a complete I-V curve from an ion saturation region to an electron saturation region needs to be obtained, and the magnitude of the voltage applied to the probe needs to be changed continuously during the process, so that the probe current is collected. In order to obtain an accurate diagnosis result, a fine structure of an I-V curve needs to be obtained, the number of collected points cannot be too small, and generally the number of collected points of a complete I-V characteristic curve is more than 100. The influence of hardware acquisition speed, interface communication rate and plasma frequency is received, a certain time is needed for acquiring adjacent points, the influence on relatively stable plasma is not great, but considering that when space ionosphere plasma diagnosis is carried out, an aviation platform carried by a probe system moves at a high speed relative to a plasma environment, peripheral plasma is difficult to be guaranteed not to change during the period of acquiring an I-V curve, and therefore, the improvement of the spatial resolution is of great importance for ionosphere plasma detection.

Disclosure of Invention

In order to improve the spatial resolution and achieve higher accuracy in spatial ionospheric plasma diagnosis, the present disclosure provides a multi-langmuir probe ionospheric electron density rapid detection method and application. Based on the OML theory proposed by Langmuir, an extended derivation is made on the electron density acquisition method, and the present disclosure provides a high spatial resolution electron density detection method that can utilize two or more Langmuir probes set at different voltages in the electron saturation region, so that the electron density can be obtained independent of the complete I-V characteristic curve and electron temperature. Aiming at the plasma detection of the rapid change of space plasma, the spatial resolution of the detection is greatly improved.

Specifically, the technical scheme of the present disclosure is as follows:

in a first aspect of the disclosure, a method for rapid detection of ionospheric electron density for a multiple langmuir probe, the method comprising: at least two Langmuir probes are arranged in the ionized layer plasma, the voltages applied to the probes are different in an electron saturation region, and the electron density can be obtained according to the difference between the collected current value on the probe, the surface area of the probe and the applied voltage.

In a second aspect of the disclosure, a method of plasma monitoring, the method of monitoring comprising the multi-langmuir probe ionospheric electron density detection method described above.

In a third aspect of the present disclosure, the method for rapidly detecting the electron density of the ionized layer of the multi-langmuir probe or the method for monitoring the plasma is applied to the fields of energy, material chemical industry, environmental protection and defense military.

One or more technical schemes in the disclosure have the following beneficial effects:

(1) the independent solution of the electron density is extended and deduced on the basis of orbital motion limit theory (OML) proposed by Langmuir, so that the solution of the electron density is independent of a complete I-V characteristic curve and can be solved by two or more independent Langmuir probes arranged under the fixed bias voltage of an electron saturation region.

(2) Compared with a mode of scanning the probe, acquiring a complete I-V curve and calculating to obtain the electron density according to the characteristic information of the I-V curve, the detection method has the advantages that the electron density can be rapidly measured through two or more Langmuir probes, the electron density is obtained independently of the electron temperature, the complete I-V characteristic curve is obtained without needing a long time, the electron density can be completely detected only by measuring one point, the small-scale detection of the ionized layer plasma can be realized, and the spatial resolution of the plasma electron density detection is greatly improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to limit the disclosure.

FIG. 1: standard Langmuir probe I-V characteristic curves;

FIG. 2: an I-V characteristic curve obtained in a conventional manner for comparative example 1;

FIG. 3: linear fitting Electron saturation region I for example 1²-a V curve.

Detailed Description

The disclosure is further illustrated with reference to specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out according to conventional conditions or according to conditions recommended by the manufacturers.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The reagents or starting materials used in the present invention can be purchased from conventional sources, and unless otherwise specified, the reagents or starting materials used in the present invention can be used in a conventional manner in the art or in accordance with the product specifications. In addition, any methods and materials similar or equivalent to those described herein can be used in the methods of the present invention. The preferred embodiments and materials described herein are intended to be exemplary only.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, and/or combinations thereof, unless the context clearly indicates otherwise.

Currently, for maxwell distributed plasma, the langmuir probe diagnosis method based on the OML theory is one of effective methods for in-situ diagnosis of plasma, and is widely applied to space ionosphere and laboratory plasma diagnosis. However, the electron density obtained by adopting the traditional diagnosis theory depends on a complete I-V characteristic curve, a certain time is needed for acquiring the complete I-V characteristic curve, and when the plasma environment is changed rapidly, the result obtained by the method is not credible. To address this issue, the present disclosure provides a method for multi-langmuir probe ionospheric electron density probing.

In one embodiment of the present disclosure, a method for rapid detection of ionospheric electron density for a multi-langmuir probe, the method comprising: at least two Langmuir probes are arranged in the ionized layer plasma, the voltages applied to the probes are different in an electron saturation region, and the electron density can be obtained according to the difference between the collected current value on the probe, the surface area of the probe and the applied voltage.

The electron density obtained by the method does not depend on an I-V characteristic curve, the method is suitable for a space plasma environment, high-spatial-resolution sampling can be realized, and the calculation method is simple and effective. In addition, the electron density is obtained without depending on the electron temperature, a complete I-V characteristic curve is obtained without needing a long time, the small-scale detection of the ionized layer plasma can be realized, and the detection accuracy and the reliability are greatly improved.

According to the OML theory, in an electron saturation region, the relation between the current collected by a probe and the applied voltage is shown as the formula (1):

in order to obtain a high spatial resolution plasma electron density detection method, the inventor of the present disclosure performs extended derivation on the independent solution of electron density, and the derivation process is as follows:

squaring the above formula (1) yields:

using two probes set to different voltages in the electron saturation region, using I_p1,I_p2Respectively representing the current, V, collected at the two probes₁,V₂Respectively, the voltages applied to the probe with respect to the plasma potential.

The difference is made by the square of the two probe currents:

the formula is simplified to obtain:

in the formula (4), N_eWhich represents the electron density of the plasma and,is constant, A is the probe surface area, I_PFor one acquisition of current value, V, on the probe_PIs the voltage applied to the probe.

Therefore, according to the current values acquired at one time on different probes, the electron density can be obtained by combining the difference of the applied voltages on different probes, and a complete I-V characteristic curve does not need to be obtained.

Compared with the method of scanning the probe and acquiring a complete I-V curve (acquiring N points, generally: N >100) to obtain the electron density, the detection method only takes 1/N of the time of the traditional method, and the size of the correspondingly detected plasma is reduced to 1/N of the size of the traditional method. The electron density is calculated according to the characteristic information of the I-V curve, a complete I-V characteristic curve is not required to be obtained for a long time, small-scale detection of ionized layer plasma can be realized, the spatial resolution of plasma electron density detection is greatly improved, and the accuracy and the reliability of detection results are improved.

Further, the applied voltage value is any value higher than the plasma space potential; preferably, the applied voltage (Vb) should be greater than the plasma space potential (Vp) by more than 2V, i.e., (Vb > Vp + 2V).

Further, the method is applied to plasmas with velocities in a maxwell distribution, and preferably, the density ranges are as follows: 10⁷-10¹⁵m^-3。

By controlling the applied voltage, the detection accuracy and reliability can be improved, and the small-size detection of the ionized layer plasma can be further realized. In the prior art, research focuses on improvement of a Langmuir probe diagnosis system and device, and the problems that the traditional detection method is long in time consumption, low in spatial resolution, poor in reliability of detection results and incapable of realizing small-size detection of ionized layer plasma are not realized.

Further, the Langmuir probes are separated by 10-30 Debye lengths.

Further, the detection method takes 1ms for the electron density under the condition that the acquisition frequency of an electronic system is 1 kHz.

However, the detection method of the present disclosure breaks the conventional approach, and by extending the derivation of the independent solution of electron density, a method that can be solved by two or more independent langmuir probes set under the fixed bias in the electron saturation region is found, thereby avoiding the acquisition of a complete I-V curve, and improving both the detection efficiency and the detection accuracy.

The conventional method requires voltage scanning of the probe for a complete cycle and then solving for electron density, which is time consuming. With the improved method of the present disclosure, two or more probes are used, and it is only necessary to set the probes to a fixed voltage, and no scanning is required.

In one embodiment of the present disclosure, a plasma monitoring method comprises the multi-langmuir probe ionospheric electron density detection method described above.

In one embodiment of the present disclosure, the multi-langmuir probe ionosphere electron density detection method is applied to the fields of energy, material chemical industry, environmental protection and defense military.

In order to make the technical solutions of the present disclosure more clearly understood by those skilled in the art, the technical solutions of the present disclosure will be described in detail below with reference to specific embodiments.

Example 1

The multi-Langmuir probe ionosphere electron density detection method specifically comprises the following steps:

(1) two or more Langmuir probes are fixed in the plasma to be detected, and the two Langmuir probes are separated by 10 Debye lengths, so that the influence of a sheath layer is prevented;

(2) and securing the probe leads to an electronic system, wherein the electronic system undertakes two operations: 1. applying a fixed voltage bias to the probe to make the probe obviously higher than the space potential of the plasma to be detected; 2. collecting the current magnitude on the probe and quantifying;

(3) obtaining plasma electron density by using the difference value of the collected current and the applied voltage bias;

at a plasma density of 10¹³m^-3Experiments were performed under conditions where two probes were set at 2.5V and 5V (experimental plasma space potential about-3.5V), respectively, and the electronic system acquired a frequency of 1 kHz.

Through the method, the detected electron density is 2.251 multiplied by 10¹³m^-3It took 1ms to obtain the electron density.

Comparative example 1:

the ionized layer electron density is tested by adopting a traditional method, and the method comprises the following steps:

(1) fixing a single Langmuir probe in the plasma to be detected, wherein the distance between the probe and other objects is more than 10 Debye lengths, so that the influence of a sheath layer is prevented;

(2) and securing the probe leads to an electronic system, wherein the electronic system undertakes two operations: 1. applying a scanning voltage of-10V-10V to the probe; 2. collecting the current magnitude on the probe and quantifying;

(3) drawing by using the acquired current and the scanning voltage to obtain an I-V characteristic curve;

(4) obtaining electron temperature by taking logarithmic fitting according to the transition region of the I-V characteristic curve;

(5) obtaining the plasma density according to the current magnitude corresponding to the first derivative maximum value (inflection point) of the I-V characteristic curve and the electron temperature;

at a plasma density of 10¹³m^-3The experiment is carried out under the condition that scanning voltage of-10V to 10V is applied to the probe, 1000 points are collected in the whole I-V characteristic curve, and the collection frequency of an electronic system is 1 kHz.

The electron density obtained by the above method is 2.207 × 10¹³m^-3And it takes 1000ms to obtain the electron density. .

Based on example 1 and comparative example 1, it is demonstrated that the conventional detection method takes a long time, and the method disclosed by the invention improves the detection speed by 1000 times.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.