TWO DIMENSIONAL HYDRODYNAMIC AND KINETIC DESCRIPTION OF A DIELECTRIC BARRIER DISCHARGE (DBD) IN NITROGEN AT ATMOSPHERIC PRESSURE

A two dimensional, axial symmetric, computational model [1] of a filament formation in a Dielectric Barrier Discharge (DBD) for short gaps (1mm-2mm) in Nitrogen at atmospheric pressure is proposed. Special attention is drawn on the interaction of the filament with the dielectric material. It is shown that with the appropriate selection of boundary conditions and the inclusion of a suitable secondary electron emission mechanism from the dielectric it is possible to model the behavior of the discharge near the cathode. The model reproduces the radial expansion of the channel on the dielectric's surface and reveals a non uniform charging of the dielectric. Furthermore, the hydrodynamic description is coupled with a kinetic one, in order to calculate the spatiotemporal evolution of excited species produced during the micro-discharge development phase and which can intervene to surface treatment applications. Special attention is drawn on the N-2(C-3 Pi(u)) and N-2(+)(B-2 Pi(u)) excited states which are responsible for the emission of the second positive and the first negative system of Nitrogen. Thus the luminous activity during the discharge phase can be modeled and compared with experimental results.