直流大气压辉光放电高能电子密度的空间分布

Spatial Distribution of Electrons with High Energy in Atmospheric Pressure Glow Discharge Excited by DC Voltage

利用针阴极和水阳极,在6mm的空气隙产生了大气压空气辉光放电。该大气压辉光放电具有明显的负辉区、正柱区和阳极辉区等明亮的发光区。通过研究放电的电压电流特性,发现该放电处于亚辉光放电到正常辉光放电阶段。由于氮分子第二正带系337.1nm的光谱强度反映高能电子密度,对337.1nm谱线的强度进行了空间分辨测量。结果发现高能电子在针尖附近密度最大,而其他区域相差不多。随电压升高,高能电子密度减少。增大限流电阻,高能电子密度也减少。氧原子对杀菌消毒具有重要作用,利用发射光谱法对氧原子谱线强度的空间分布进行了测量,发现氧原子谱线强度与高能电子的空间分布及其随参数的变化关系一致。

Atmospheric pressure glow discharge excited by a DC voltage was realized in a 6mm air gap by using a needle-water electrode discharge device.The atompheric pressure glow discharge has characteristic regions such as a cathode fall,a negative glow,a Faraday dark space,apositive column and an anode glow.The discharge is a normal glow through analyzing its voltagecurrent curve.The emission intensity of 337.1nm spectral line from the second positive system of N2 was investigated because it can indicate the electron density with high energy.Results show that the maxima of high energy electrons appears in the vicinity of the needle tip,and it almost remains constant at other locations.The density of high energy electrons decreases with increasing the voltage.Similarly,it decreases with increasing the value of the ballast resistor.Oxygen atom is important for the sterilization and disinfection.The distribution of oxygen atom was also investigated by optical emission spectroscopy.It was found that the oxygen distribution is similar with the distribution of high energy electrons.These results are important for the application of atmospheric pressure glow discharge in environmental protection and biological treatment.