Spatially resolved surface-charge measurement in a planar dielectric-barrier discharge system

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.