3D Imaging of the Single Microdischarge Development in Coplanar Barrier Discharges in Synthetic Air at Atmospheric Pressure

The evolution of the luminosity of the coplanar barrier discharge in the single-filament mode was studied by the technique of cross-correlation spectroscopy and intensified high-speed CCD camera. For the first time 3D-spatially and temporally resolved investigations of the luminosity of second positive (at 337.1 nm) and first negative (at 391.5 nm) system of molecular nitrogen in this discharge type were realized. Although the coplanar barrier discharge is sometimes referred to as a pure surface discharge, it shows clear 3D structure. From these experimental data, the propagation of the cathode-directed ionizing wave in the space above the gap is clearly seen. Also, a second ionizing wave propagating towards anode later on has been detected, too. The diffuse spots created by impact of ionizing waves onto the dielectrics and their propagation on the dielectric surface is described. The results for the coplanar barrier discharge are compared with corresponding experimental results obtained for the volume barrier discharge and basic similarities are pointed out. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim