发射光谱法诊断空气电弧的稳态电子密度分布

Diagnosis of Steady State Electron Density Distribution in Air Arc by Emission Spectroscopy

空气电弧是一种常见的等离子体,对其稳态阶段的微观参数进行研究,对准确把握等离子体内部的反应机制有重要意义。发射光谱法是一种成熟的诊断等离子体电子密度的技术,具有非接触式测量、瞬态探测、灵敏度高、响应速度快、仪器简单等优点。文中以H_(α)656.28 nm谱线做特征谱线,以石墨为电极材料在250 A、200 V的条件下对空气电弧进行发射光谱的测量,对实验获得的发射光谱作阿贝尔反变换和佛克脱线型拟合,反卷积得到斯塔克展宽,最终获得空气电弧电子数密度的径向分布。同时利用汤姆逊散射法测量相同参数条件下空气电弧的电子数密度以验证发射光谱法测量结果的正确性,经验证两种方法的测量结果具有良好的一致性。该实验为空气电弧等离子体电子数密度的测量提供了参考思路和方法。

The air arc is a common plasma,and the study of its microscopic parameters in the steady state stage is of great significance for accurately grasping the reaction mechanism inside the plasma.Emission spectroscopy is a mature technique for diagnosing plasma electron density,which has such advantages as non-contact measurement,transient detection,high sensitivity,fast response,and simple instrumentation.In this paper,the H_(α)656.28 nm spectral line is used as the characteristic spectral line,and graphite is used as the electrode material to measure the emission spectrum of the air arc under the conditions of 250 A and 200 V.Abelian inverse transformation and Viogt off-line fitting are performed on the emission spectrum obtained from the experiment,Stark broadening is obtained by deconvolution,and finally the radial distribution of the air arc electron number density is obtained.At the same time,the Thomson scattering method is used to measure the electron number density of the air arc under the same parameter conditions to verify the correctness of the emission spectrometry measurement results.It is verified that the measurement results of the two methods have good consistency.This experiment provides a reference idea and method for the measurement of air arc plasma electron number density.