纳秒脉冲下CO₂/He气体均匀放电特性

Non-thermal plasma is very promising in the CO₂ conversion application and it has become a worldwide research hotspot. However, the discharge in CO₂ always transits into arc or filament mode when microwave or dielectric barrier discharge is adopted. It is difficult to regulate the electrical parameters of discharge, which limits the in-depth study of the conversion mechanism. We proposed a method to obtain a uniform CO₂/He discharge with plate-to-plate bare electrodes excited by nanosecond pulsed voltage. The ignition voltage and stable discharge voltage were obtained. It was found that the stable discharge voltage became higher when the CO₂ proportion was higher or the pulse repetition frequency (PRF) was lower. The discharge stability were investigated under different conditions using discharge images and optical emission spectra. Stable discharge exhibited glow discharge mode during the dominant discharge, followed by multiple afterglows similar to the Townsend discharge. Furthermore, spectral line intensity ratio r(O₂/He) and the relative intensity of CO band CO(B¹∑→A¹∏) are analyzed respectively. The discharge has shown memory effect in repetitive nanosecond pulsed discharge.