大气压微等离子体射流电子密度研究

采用微空心阴极放电装置，利用光学方法和电学方法研究了大气压流动Ar和N₂混合气体中产生的微等离子体射流特性。研究发现，随着电源输入功率增大到一定数值，微空心阴极装置中两个电极间气体发生击穿，通过击穿气隙气体的流动会沿着气流方向产生最大为4 mm的等离子体射流。放电电流为准连续的脉冲放电形式，其中放电电流脉冲宽度约为0.1 μs。分别利用爱因斯坦方程和等离子体发射光谱中谱线的Stark展宽方法计算了电子密度。结果发现，2种计算方法得出的微等离子体射流的电子密度均在1015·cm-3的量级。研究还发现，功率对微等离子体射流电子密度影响不大。利用气体击穿理论，对以上结论进行了定性分析。

Investigation on the Electron Density of a Micro-Plasma Jet Operated at Atmospheric Pressure

In the present paper, a micro-hollow cathode discharge setup was used to generate micro-plasma jet in flowing mixture of Ar and N₂ at atmospheric pressure. The characteristics of the micro-plasma jet were investigated by means of optical method and electrical one. It has been found that breakdown occurs in the gas between the two electrodes when the input power of electric source is increased to a certain value. Plasma appears along the gas flow direction when the mixed gas flows from the aperture of the micro-hollow cathode, and the length of plasma reaches 4 mm. The discharge current is quasi-continuous, and the duration of discharge pulse is about 0.1 μs. Electron density was studied by using Einstein equation and Stark broadening of spectral lines from the emission spectrum respectively. It was found that the results of electron density calculated by the two methods are consistent with the order of 1015·cm-3. It was also found that the electron density is almost independent of power. A qualitative explanation to the phenomenon is given based on the gas discharge theory.