基于气隙伏安特性研究大气压氦气辉光放电的模式和机理

Mode and Mechanism of Multi-Pulse Glow Discharges in Helium at Atmospheric Pressure Based on Voltage-Current Characteristics

进行了单脉冲和多脉冲辉光放电试验,通过拍摄放电空间的ICCD短时曝光图像,研究了大气压多脉冲辉光放电的模式;通过测量外加电压和回路电流,计算了气隙的放电电压、放电电流、介质表面电荷和气隙放电的伏安特性曲线,探讨了多脉冲辉光放电的物理过程,研究了伏安特性曲线诊断大气压介质阻挡放电模式的可行性。结果表明:外加电压及其造成的放电积聚在介质的表面电荷,使辉光放电具有多脉冲的电流波形,外加电压升高促进放电,表面电荷积累抑制放电,但是起主导作用的是外加电压升高抑制作用不会超过促进作用造成放电熄灭,脉冲之间辉光放电并未熄灭;伏安特性曲线只能诊断多脉冲辉光放电的第一个脉冲的放电模式,即具有正特性时为汤森放电,具有负特性时为辉光放电,对后续脉冲伏安特性曲线不能用来诊断放电模式。

Single pulse and multi-pulse glow discharges in helium at atmospheric pressure are carried out with dielectric barrier electrodes. By taking fast images of the discharges using an intensified charge couple device, the modes of discharges are investigated. Based on the measured current and the applied voltage, the discharge voltage across the gas gap, discharge current, accumulated charges on dielectric surface and the voltage-current characteristics are calculated. The application of voltage-current characteristics to discharge mode diagnosis is investigated, and physical mechanisms of discharges are discussed. The results show that the applied voltage and accumulated charges on dielectric surface due to discharge result in multiple current pulses, and the increase of applied voltage contributes to discharge, while accumulation of surface charges restrains to discharge. The contribution action of increasing applied voltage plays a master role, the restrain action of the accumulated charges can not surpass the contribution action, and thus the discharge does not extinguish among the pulses. The current-voltage characteristic, which is positive means the discharge is a Townsend discharge and negative means a glow one, can only diagnose the discharge mode of the first pulse. In the case of subsequent pulses, the characteristic can not diagnose the discharge mode.