实验研究大气压多脉冲辉光放电的模式和机理

采用稍不平行电极进行大气压He气介质阻挡多脉冲辉光放电实验，通过增强电子耦合器件相机短时曝光照片，研究大气压多脉冲辉光放电在不同时刻的放电模式.通过气隙放电电流、表面电荷计算，理论分析了表面电荷、空间电荷、外加电压与气隙电场强度的关系，研究大气压辉光放电形成多脉冲的机理.实验结果表明，放电首先在间隙稍窄的电极左端开始；在第一个脉冲电流峰值，电极右端也开始放电；第一个电流脉冲经历了Townsend放电到辉光放电的过程；电流脉冲之间的时间内，间隙一直维持着微弱的辉光放电；随后的每个电流脉冲均是辉光放电.理论分析表明，大气压辉光放电的多个电流脉冲是表面电荷、空间电荷与外加电压共同演化的结果；除放电伊始出现Townsend放电外，同一半周期内的放电电流脉冲中不会再出现Townsend放电.

Experimental study on mode and mechanism of multi-pulse atmospheric-pressure glow discharges

Multi-pulse atmospheric-pressure glow discharges between two slightly unparallel electrodes were carried out in helium. The mode of discharge was investigated using an intensified charge-coupled device camera. The discharge current through gas gap and surface charge on the solid dielectric barrier were calculated. Based on analysis of surface charge on the solid barrier, space charges in gas gap, applied voltage across electrodes and field strength in gas gap, the formation mechanism of multi-pulse discharge was discussed. The discharge evolution pictures show that discharge is generated at the narrower side. At the other side, discharge is also generated at the first current peak. Physical process of the first pulse of atmospheric-pressure glow discharge in helium starts from a Townsend discharge leading to a glow discharge, and that of each subsequent current pulse is a glow discharge. Between two consecutive current pulses, a faint glow discharge is maintained in the gas gap. Theoretical analysis shows that multi-pulse discharge is a result of co-evolution of both surface charge as well as space charge and applied voltage, and the Townsend discharge does not appear during current pulse sequence of the same half cycle, except for discharge inception.