We report on pattern formation phenomena in the filamentary dielectric barrier discharge between plane glass electrodes. It is for the first time that a three-dimensional (3D) self-organized glow pattern was both observed in an actual experiment and directly calculated in a full 3D discharge simulation in a quantitative manner. Specifically, we investigate the genesis of periodic patterns during the first breakdowns. Despite our simple drift-diffusion discharge model, the correspondence of experimental and numerical findings is surprisingly good.

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We investigate a laterally extended dielectric helium discharge system with plane electrodes. The system is operated in the glow mode and is known to exhibit a rich variety of self-organized lateral patterns in the current distribution, most of them being filamentary. It is known from theory that surface charges on the dielectrics play a major role for the emerging patterns. In this work we present a method to measure the spatial charge distribution on the dielectrics via the Pockels effect of a bismuth-silicon-oxide crystal. The experimental results of the surface-charge distribution measurements are in good agreement with previous numerical solutions of the corresponding transport equations.

Abstract. In a planar, laterally extended dielectric barrier discharge (DBD) system operated in glow mode, a filamentary discharge is observed. The filaments tend to move laterally and hence tend to cause collisions. Thereby, usually one collision partner becomes destroyed. In this paper, the collision process and especially the preceding time period is investigated. Beside the luminescence density of the filaments, the surface charge density accumulated between the single breakdowns of the DBD is observed via an optical measurement technique based on the linear electro-optical effect (pockels effect). A ring-like substructure of the surface charge distribution of a single filament is found, which correlates to the filament interaction behaviour. Furthermore, a preferred filament distance is found, suggesting the formation of a filamentary quasi-molecule.

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