Influence of Voltage Pulse Off-Time on the Discharge Characteristics in Surface-Launched Plasma Bullets

We have investigated propagation characteristics of surface-launched plasma bullets (SLPBs), which are vertically launched from dielectric surface. We conducted our experiments particularly focusing on the influence of voltage pulse-off time on the plasma bullets propagation characteristics by using an ICCD camera. Comparison of sequential images captured with the ICCD camera in different pulse off-times of 28 µs and 2 µs showed that SLPB's velocity and size increase as the pulse off-time becomes shorter as opposed to the bullet-propagation characteristics observed in conventional APPJs. These results indicate that the SLPBs may propagation scheme is somewhat different from those of conventional plasma bullets launched from a tube. The reason for our results may be related to the charge accumulation on the inner wall of the quartz tube and/or in the gas phase chemistry where the previous bullet propagated. Details will be discussed based on the ICCD images captured at both positive- and negative-pulse-rise edges.