Streamer–surface interaction in an atmospheric pressure dielectric barrier discharge in argon

Abstract

An atmospheric-pressure dielectric barrier discharge (DBD) in argon is investigated using a time-dependent and spatially two-dimensional fluid-Poisson model in axisymmetric geometry. The focus is on the streamer-surface interaction and the cathode-layer formation during the first discharge event in the single-filament DBD driven by sinusoidal voltage. A characteristic structure consisting of a volume streamer propagating just above the dielectric and simultaneous development of an additional surface discharge near the cathode is observed. The analysis of the electric field, electron production and loss rates, and surface charge density distribution shows that the radial deflection is driven by free electrons remaining in the volume from the Townsend pre-phase and guided by the radial component of the electric field. The surface discharge occurring between the deflected volume streamer acting as virtual anode and the dielectric surface is governed by ion induced secondary electron emission and the surface charges accumulated on the dielectric.

Formation mechanisms of striations in a filamentary dielectric barrier discharge in atmospheric-pressure argon

“…The discharge was initiated by the increased voltage amplitude, which leads to a strong discharge in the first half-period. The features of this particular discharge have been investigated recently [45]. After the occurrence of the first discharge event, two periods of the applied sinusoidal voltage were required to establish a quasi-periodic state.…”

“…The same time-dependent, spatially two-dimensional fluid-Poisson model as in [44,45] was used in the present study. It comprises the balance equations for the particle number densities of all considered species, the electron energy balance equation and Poisson's equation.…”

“…The used reaction-kinetic model for argon involves the species Ar, Ar * , Ar * 2 , Ar + , Ar + 2 and electrons [38,45]. Note that Ar * and Ar * 2 represent lumped excited atomic and molecular (excimer) states, containing all higher excited levels.…”

“…To this end, the present article investigates striated structures in a singlefilament DBD in pure argon at atmospheric-pressure by means of a well-established fluid-Poisson model. While the same model has been used in [44,45] to analyse the formation of the very first (non-striated) discharge channel and the streamersurface interaction in the DBD, it is used here to study the particle gain and loss processes as well as the electron energy budget under periodic conditions. In fact, this represents the first in-depth analysis of the formation mechanisms of striations in a filamentary DBD at atmospheric pressure.…”

Experimental study of transient surface charging during dielectric barrier discharges in air gap in needle-to-plane geometry

“…The electron avalanches and streamers can develop in the air gap under the high electric field. As the volume steamer approaches the surface, it is deflected, and the electric field distribution also changes with a significant increase in its radial component [59], such that the streamer expands over the surface and the radial development begins. Figure 6(b) shows the surface charge distributions before and after the arrival of the streamer on the dielectric surface.…”