Reverse Propagation of Atmospheric Pressure Plasma Jets

Bullet-like propagation of individual bright spots has been observed using photomultiplier tubes in helium atmospheric pressure plasma jets with dielectric barrier discharges. Under typical discharge conditions, such optical-emission spots in plasma jets (also known as plasma bullets'') are known to propagate in the direction of the applied electric field. Results of this study show that similar optical-emission spots can also propagate in the reverse direction under certain conditions. The direction and velocity of such a reverse propagating plasma bullet'' are found to resemble those of the electron drift velocity. (C) 2010 The Japan Society of Applied Physics