Mechanism of glow discharges in helium at atmospheric pressure based on voltage-current characteristics

Glow dielectric barrier discharges (DBD) were carried out under an 11.85 kHz voltage in helium at atmospheric pressure. Discharge current, voltage, and accumulated charges on dielectric surfaces were calculated, and discharge images were taken by an intensified charge-coupled device (ICCD) digital camera in an exposure time of ns orders. Based on voltage-current characteristics of the discharge gas gap, physical processes of discharges were discussed. The results show that the process of the first discharge current pulse for a glow DBD in helium at atmospheric pressure is from a none-self-sustained discharge via a Townsend one to a glow one. The process of the other discharge current pulses is to maintain the glow one, due to no ending of the glow discharge during the preceding discharge current pulse.