Traces of cathode glow in atmospheric surface dielectric barrier discharge

Owing to the cathode layer properties in atmospheric surface dielectric barrier discharges (SDBDs), the discharges are sustained both for positive and negative voltage phase. There should be the cathode glow region where excited molecules or atoms are produced due to collision with the electrons before occurrence of electron-ion breeding in the cathode layer. Although a previous numerical study reported the generation of oxygen atoms, O(1D), O(3P), near an exposed electrode (EE) during the negative voltage phase, it is experimentally unattainable to verify the existence of the oxygen atoms because of the short length of the cathode layer with a thickness of approximately 20 μm at 1 atm in filamentary discharge mode. This work presents the experimental confirmation of trace(s) of O and N, which indicates the cathode glow, in a cathode layer in atmospheric SDBDs using ultra-fine surface polyimide as a dielectric in SDBD. Our results show that the cathode glow in atmospheric SDBD is located at approximately 5∼6 μm from EE in air.