Experiments and numerical simulation on the plasma bullets launched vertically from a dielectric surface

We have found that plasma bullets can be launched vertically from a plane surface of a dielectric plate, as opposed to the fact that conventional plasma bullets are mostly launched from a nozzle of a dielectric tube. We call such plasma bullets as Surface-Launched Plasma Bullets (SLPBs). This phenomenon has possibility to be applied to large area and/or large volume treatments by atmospheric-pressure plasma because the SLPBs propagates as sheet-like bullets. However, the SLPBs were available only for high voltage-rise rate greater than 30 kV/s. For understanding the reasons of this limitation, we are conducting numerical simulation of the SLPB propagation with different voltage-rise rates and discuss the reason of the limited availability of SLPBs from the viewpoint of trade-off between the rise rate in the local ionization rate and the loss of the local space charges near the dielectric surface at the very initial stage of launching the plasma bullet.