Measurement Method of Time-varying Plasma Electron Density Jitter Frequency

A plasma and electron density technology, applied in the direction of plasma, electrical components, etc., can solve the problems of time-consuming, measurement efficiency that cannot satisfy the analysis of plasma dynamic characteristics, and the inability to obtain the jitter frequency of plasma electron density in a single measurement.

Active Publication Date: 2021-07-20
XIDIAN UNIV
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Problems solved by technology

Using the current method to measure the electron density jitter frequency is complicated and takes a long time. It is impossible to obtain the plasma electron density jitter frequency through a single measurement, and the measurement efficiency cannot meet the needs of plasma dynamic characteristics analysis and research.
[0004] The applicant of the present invention searched and searched for novelty in the relevant scope, but did not find the literature and reports of the instantaneous variable plasma electron density jitter frequency measurement method related to the subject of the present invention

Method used

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  • Measurement Method of Time-varying Plasma Electron Density Jitter Frequency
  • Measurement Method of Time-varying Plasma Electron Density Jitter Frequency
  • Measurement Method of Time-varying Plasma Electron Density Jitter Frequency

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Effect test

Embodiment 1

[0030] The current measurement methods for plasma electron density are all for measuring the static value of instantaneous electron density. For the dynamic parameter of time-varying plasma electron density jitter frequency, the existing methods cannot effectively measure the jitter frequency through a single measurement. . The present invention conducts research on this, and proposes a method for measuring the jitter frequency of time-varying plasma electron density.

[0031] The present invention is a method for measuring the jitter frequency of time-varying plasma electron density, see figure 1 , the method for measuring the jitter frequency of the time-varying plasma electron density includes the following steps:

[0032] S1 Obtain the chirp signal echo of the time-varying plasma: point the transmitting antenna at the part on the plasma that needs to be measured, generate a chirp signal through the transmitter, and transmit it to the time-varying plasma, and what needs to...

Embodiment 2

[0041] The method for measuring the jitter frequency of the time-varying plasma electron density is the same as in Example 1, and the determination of the jitter frequency calculation formula is as follows:

[0042] S3.1 Determine the reflection signal of the time-varying plasma, specifically expressed as follows:

[0043] Set the carrier frequency f of the chirp signal 0 , the pulse width is T p , the signal bandwidth is B, the modulation frequency is μ, and a linear frequency modulation pulse signal is generated, the expression is as follows:

[0044]

[0045] Transmitting a chirp signal into the time-varying plasma, the jittering mode of the plasma electron density is sinusoidal, and the expression of the electron density is as follows:

[0046] Ne tv (z,t)=Ne(z)(1+σsin(2πf Ne t))

[0047] Ne(z) is the distribution of electron density along the thickness, σ is the jitter coefficient, f Ne is the jitter frequency, that is, the item to be tested.

[0048] Using the ...

Embodiment 3

[0075] The present invention is also an application of a time-varying plasma electron density jitter frequency measurement method. The time-varying plasma electron density jitter frequency measurement method is the same as that in Embodiment 1-2. The application of the time-varying plasma electron density jitter frequency measurement method includes: :

[0076]1) It is used to calculate the time distribution of the plasma electron density jitter frequency: in the plasma ground experiment, the plasma in the experimental device changes in real time, and the real-time change of the plasma causes the real-time change of the electron density jitter frequency. The time-varying plasma electron density jitter frequency measurement method is used to obtain the time distribution of the plasma electron density jitter frequency in the experimental device by measuring the same position of the plasma at different times.

[0077] In the plasma ground experiment, it is necessary to simulate t...

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Abstract

The invention discloses a method for measuring the jitter frequency of time-varying plasma electron density, which solves the problem that the existing measurement method cannot obtain the jitter frequency of the electron density by single measurement. The implementation includes: transmitting the linear frequency modulation signal to obtain the reflection signal of the time-varying plasma; calculating the one-dimensional range image of the echo to confirm the peak expansion phenomenon; calculating the time-varying plasma electron density jitter frequency through the jitter frequency calculation formula. The invention is also an application of a time-varying plasma electron density jitter frequency measurement method, which can be used to calculate the distribution of plasma electron density jitter frequency in time and space, and the plasma interference compensation parameters in the reentry spacecraft communication system. The invention calculates the electron density jitter frequency back by measuring the peak extension distance in the one-dimensional range image, obtains a simple and effective jitter frequency measurement method, and provides a measurement method for the plasma electron density dynamic parameters in the ground plasma experiment.

Description

technical field [0001] The invention belongs to the field of plasma parameter measurement, and mainly relates to the measurement of plasma dynamic parameters, in particular to a method for measuring the jitter frequency of time-varying plasma electron density, which can be used to measure the dynamic characteristics of time-varying plasma. Background technique [0002] During the return phase of the re-entry spacecraft, the speed can reach tens of Machs. The surface of the spacecraft and the atmosphere will have a strong interaction, forming a shock wave at the head of the spacecraft. The temperature and pressure of the gas will increase sharply, ionizing the atmosphere, and the surface of the spacecraft will be A layer of plasma is generated, and the plasma will seriously interfere with the spacecraft's sending and receiving signals, affecting the communication between the ground and the spacecraft. During the return process of the spacecraft, atmospheric turbulence will ca...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H05H1/00
CPCH05H1/0081
Inventor 谢曜聪沈方芳白博文李小平陈旭阳刘彦明
Owner XIDIAN UNIV
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