介质阻挡放电六边形斑图稳定过程的光谱研究

采用发射光谱法，首次研究了等离子体参数及激发状态对介质阻挡放电六边形斑图稳定性的影响。在氩气/空气混合气体的介质阻挡放电中，随着电压的升高，放电丝直径增大，六边形斑图逐渐稳定，同时放电颜色由紫色逐渐变为灰白色，说明其等离子体状态及参数可能发生了变化。测量了六边形斑图放电过程中氮分子谱线和氩原子谱线相对于氩原子763.51 nm的相对强度、分子振动温度和电子激发温度随外加电压的变化。结果发现：氮分子谱线相对强度随电压增加而降低，氩原子谱线相对强度却升高；分子振动温度与电子激发温度均随电压增加而增大。这些现象表明：随着电压增大，电子能量增加。由此，氩原子激发增多，放电丝直径增大，介质表面上沉积的壁电荷面积增大，放电丝之间的相互作用增强，六边形斑图趋于稳定。

Study on Stable Process of Hexagon Pattern in Dielectric Barrier Discharge by Optical Emission Spectra

The effect of plasma parameters and excited states on the stable process of the hexagon pattern in a dielectric barrier discharge was studied by using optical emission spectra. It was found that the diameter of the discharge filament increases, the pattern gets more stable, and the color of the pattern changes from purple to gray with the increase in the voltage in dielectric barrier discharge in argon and air mixture. It indicates that the plasma excited states and parameters may be changed. To this end, the relative intensity of N₂ and Ar spectral lines with respect to Ar Ⅰ 763.51 nm, the molecular vibration temperature, and the electron excitation temperature were measured with the change in the applied voltage. The results show that the relative intensity of N₂ spectral lines decreases and that of Ar spectral lines increases with the increase in the voltage. And both the molecular vibration temperature and the electron excitation temperature increase. These phenomena indicate that the electron energy increases with the increase in the voltage. The increase of the stimulated argon atoms excited by higher energy electron leads to the increase in the diameters of the discharge filaments. Correspondingly, the areas of the wall charges deposited on the dielectric increase, which results in the enhancement of the interactions between filaments, and therefore the hexagon pattern becomes stable.