Continuous spectrum absolute intensity diagnosis method for electron density of Ar jet plasmas under different pressures

Abstract

The invention provides a continuous spectrum absolute intensity diagnosis method for the electron density of Ar jet plasmas under different pressures. The method includes the following steps that: step 1, the intensity change process of a light beam in jet plasmas is described; step 2, absolute radiance is determined; step 3, the expression of the emission coefficient of a continuous spectrum in the plasmas is determined; step 4, the emission coefficient expressions of the recombination process of electrons and ions, the collision effect of the electrons and ions, and the collision effect of the electrons and neutral atoms are defined, wherein the recombination process of the electrons and the ions, the collision effect of the electrons and ions, and the collision effect of the electrons and neutral atoms are respectively represented by three symbols descried in the descriptions of the invention; step 5, an average collision cross section QAr(Te) is fitted; step 6, a total emission coefficient is obtained; step 7, the expression of the total emission coefficient of which the form has been adjusted is obtained; step 8, the equation for the total emission coefficient is solved; and step 9, Taylor expansion is performed on the sign of evolution of a solution, so that the electron density is obtained. The diagnosis method of the invention has the advantages of wide application range and low cost.

Description

technical field [0001] The invention relates to a continuous spectrum absolute intensity diagnosis method suitable for electron density of Ar jet plasma with different pressures, belonging to the technical field. Background technique [0002] The basic parameters of plasma mainly include gas temperature, electron temperature and electron density. The qualitative and quantitative measurement of these three parameters is the basis for studying the properties of plasma jets. Among them, the commonly used diagnostic method for electron density is the Stark broadening method of atomic spectral lines. The Stark broadening of hydrogen atomic spectral lines is weakly affected by electron temperature and gas temperature, and has a linear relationship with electron density. The Stark broadening analysis has been developed into a more mature electron density diagnostic technique. When there is no hydrogen atomic line in the plasma, a small amount of hydrogen can be mixed in the worki...

AI Technical Summary

Problems solved by technology

However, due to the weak luminous intensity and small size of the low-temperature plasma jet at atmospheric pressure, it is difficult to measure the electron density in the jet effectively by millimeter-wave interferometry.

Thomson scattering technology can directly measure plasma electron density, but this diagnostic technology requires expensive laser equipment and precise optical path design, and it is difficult for general research teams to have such expensive experimental conditions; using Stark broadening of atomic spectral lines The method can diagnose the electron density of the plasma jet. This technique is simple and the cost of experimental equipment is lower than that of laser equipment. However, due to the small size of the jet and the weak light intensity, it is generally necessary to collect the light of all jets to increase the experimental signal. Signal-to-noise ratio, which can only be obtained relative to the average electron density of the entire jet plasma, and in fact, because the spectral line is simultaneously affected by various other broadening mechanisms, especially pressure broadening, resulting in Stark broadening and Not suitable for density below 10 20 m -3 It is not suitable for the study of high-pressure plasma

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