不同电极间距下纳秒脉冲表面介质阻挡放电分布特性

电极间距是表面介质阻挡放电(SDBD)的一个重要结构参数。通过实验研究和仿真计算,研究电极间距对纳秒脉冲SDBD等离子体分布特性的影响,并从理论上分析类弥散和离散通道两种等离子体分布的形成机制。实验研究表明,电极间距是造成两种典型特性及不同等离子体分布的关键结构参数。通过对放电区域外电场的仿真计算发现,不同电极间距下外电场分布形态和数值的差异,是形成两种不同等离子体分布模式的直接原因。结合气体放电基本理论,分析认为:等离子体类弥散分布是由于流注前向发展和横向激发电离同时在起作用,而离散通道分布是因为流注通道以前向发展为主、横向电离作用较弱;两种等离子体分布模式形成的根本原因在于电场随时间的增大率和随空间的减小率以及流注通道的发展速度之间的匹配。

Distribution Characteristics of Nanosecond-Pulsed Surface Dielectric Barrier Discharge at Different Electrode Gaps

Electrode gap is an important geometric parameter in surface dielectric barrier discharge (SDBD).Based on experimental studies and simulations,the influence of electrode gaps on the distribution characteristics of nanosecond-pulsed SDBD is studied,and the mechanisms of two plasma distributions (quasi-diffuse mode and separated-channel mode) are analyzed theoretically.Experimental results show that electrode gap is the key geometric parameter accounting for the two typical discharge characteristics and different plasma distributions.Simulations of external electric fields of discharge areas present that the direct reasons of two plasma distributions are the morphological and numerical differences of external electric fields at different gaps.Combined with gas discharge theory,it is deduced that the quasi-diffuse distribution is due to that the streamers forward-expanding and spanwise-exciting ionization act simultaneously,while the separated-channel distribution is mainly because the streamer forward expanding is dominant and span-wide ionization is relatively weak.The main mechanisms are the match of the changing rate of electric field with time and space,and the expanding velocity of streamer channels.