Concentric-roll pattern in a dielectric barrier discharge in air

Concentric-roll pattern in a dielectric barrier discharge in air at pd value 29.3 hPa cm is observed in the presence of circular boundary and studied by an optical method for the first time. The weak correlation between microdischarges in concentric-roll patterns indicates that the concentric roll is a spatiotemporal chaos although the space integral of microdischarges is quasiperiodic in time. Spatiotemporal measurements of microdischarges suggest that the effective electric field near the boundary is weaker than that in the interior region. The bifurcation of concentric-roll patterns with the increase of voltage and selection of characteristic wavelength are also studied. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3466854]