Student Excellence Award Finalist: Self organization of streamers in a surface DBD: evidence of collective breakdowns

Surface dielectric barrier discharges (DBD) are mainly investigated for airflow control. In this paper, surface processes controlling the filament development are studied. Recent results have shown that in a cylindrical DBD, most of the energy is transferred via few large amplitude current peaks called collective effects [1]. To get further in the study of this phenomenon, electrical measurements and CCD imaging have been performed on a surface discharge, were the plasma filaments are generated onto the dielectric surface. The plasma is generated via several nearby (but distinct) filaments occurring simultaneously, the current peak duration being a few tens of nanoseconds. The current peak amplitude is proportional to the number of filaments, with a value of about 40 mA/filament. The filament length depends on the applied and breakdown voltages, independently from the current amplitude. The self-organization of the streamer breakdown in adjacent patterns is due to the simultaneous triggering of individual filaments via a collective effect. We suggest that the origin of such a self triggering is due to the photo-desorption of electrons from the surface by a first filament. These electrons then initiate the neighbouring filaments, and all the filaments contribute to the whole charge transfer. [1] O. Guaitella et .al, Phys. D.: Appl. Phys. 39(2006)