Study on the polarity effect in an atmospheric pressure glow discharge driven by resonant power supply

In recent years, atmospheric pressure glow discharge has become an active research area for many scholars because of its broad industrial application prospects. However, much of the research is focused more on how to acquire this type of discharge or how to use it in some fields; there is a lack of clear and universally accepted theories. In this paper, we described the polarity effect in the process of atmospheric pressure glow discharge driven by a resonant power supply, from the standpoint of the differences in electric field direction in the pin-to-plate gap. We also discussed the characteristics of the discharge waveform, the characteristics of discharge images and the light-intensity distribution on the centerline of the discharge channel. Also studied were the polarity effect of unipolar discharge and the influence of different output-voltage amplitudes on the polarity effect. We found that both positive and negative discharges looked like a typical glow discharge. The voltage and current waveforms of unipolar discharge have a rapidly rising slope, and there is strong ionization near the anode. In the process of a unipolar discharge, there is an obvious gamma discharge stage, and the alpha mode discharge has an obvious high-slope stage, whereas the slope of this process of a negative discharge is more gradual, and the polarity effects of positive and negative unipolar discharges become less and less obvious with the increase in the output-voltage amplitude of power supply.