A Fundamental Study on Optical Emission Spectroscopy Measurement of Atmospheric Pressure Discharge Plasmas

研究了一种基于等离子体中氩原子激发态居群分布估计常压氩等离子体电子温度的方法。数值计算表明，由4p和5p能级填充决定的激发温度是电子温度和气体温度的函数，而当电子密度小于1012 cm-3时，其对电子密度的依赖性较弱，此时中性地原子与激发态的碰撞频率大于与电子的碰撞频率。我们发现Te和Tg两个温度都是必需的，激发态占比几乎与电子密度无关。如果我们通过其他方法（如OES测量旋转温度）确定近似气体温度，我们可以在CR模型中固定气体温度。因此，激发温度与电子温度是唯一相关的。用功率为150w的2.45 GHz微波对常压下氩等离子体进行了OES实验测量，得到电子温度约为（0.9±0.1）eV。

We studied a method to estimate electron temperature of atmospheric pressure argon plasma, based upon the population distribution of the excited populations of argon atoms in the plasma. Numerical calculations show that the excitation temperature determined by population of 4p and 5p levels is found to be a function of the electron temperature as well as the gas temperature, while its dependence on the electron density is rather weak when the electron density is less than 1012 cm-3, where the collision frequency of neutral ground atoms with the excited states is larger than that with electrons. We found that the two temperatures Te and Tg are both essential, and the ratio of excited state population is almost independent of the electron density. If we determine the approximate gas temperature by other methods like OES measurement of rotation temperature, we can fix the gas temperature in the CR model. Consequently, the excitation temperature is uniquely correlated with the electron temperature. We demonstrate experimental OES measurement of argon plasma at atmospheric pressure excited by 2.45 GHz microwave with its power 150 W and find the electron temperature about (0.9±0.1) eV.