Dynamics of apokamp-type atmospheric pressure plasma jets initiated in air by a repetitive pulsed discharge

This paper presents the research data on the dynamics of a repetitive pulsed discharge as a source of plasma jets in atmospheric pressure air and on the conditions under which the discharge produces apokamp–plasma jets ejected from the bending point of the discharge channel with no gas supply through the discharge region. The data suggest that the formation of apokamps requires the application of a large number of voltage pulses to sharp-ended electrodes at a repetition frequency of several to tens of kilohertz. Before an apokamp starts developing, the apokamp-initiating discharge passes through a spark stage and then becomes diffuse. Next, at the site of electric field amplification, the discharge channel gives rise to a bright branch from which plasma bullets escape with a velocity of ∼200 km/s. The images of different discharge and apokamp stages are presented.