Two-dimensional numerical study of a period-two dielectric-barrier discharge in atmospheric argon

A two-dimensional fluid simulation is performed on an atmospheric dielectric barrier discharge (DBD) in pure argon to explore the formation mechanism and spatiotemporal evolution of period-two DBD at atmospheric pressure. The results show that the formation of the period-two discharge is directly correlated to the spatial distribution of electron density. It is found that when under certain conditions, a local high electron density region occurs before a new discharge is ignited, and the discharge current varies in magnitude depending on whereabouts of the local high electron density region. When the local high electron density region appears near the momentary anode, it barely affects the discharge current. In contrast, when the high electron density region appears in the vicinity of the cathode, it reduces the discharge current greatly, since it restrains the growth of the electric field. The local high electron density region disappears completely before the two voltage cycles end, and thus the discharge exhibits the appearance of period-two state. The radial current and electron density distributions at different times indicate that different discharge events within one oscillation period of period-two discharge possess different radial behaviors. The causes for these radial behaviors are further analyzed and discussed in this paper. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3700176]