Gas dynamics of the high-frequency corona discharge

This paper investigates the evolution of a single-electrode high-frequency corona discharge operating in pulsed mode in air at pressures ranging from 1 to 4 atm and the gas dynamics of the heated cavern formed during the discharge process. Analysis of schlieren images reveals that the discharge cavern experiences a sinuous instability developing over a timescale of tens of microseconds. Subsequent subharmonic generation creates a turbulent region characterized by macroscopic eddies, which influence the shape of the discharge. The deformation of the discharge channel results in the branching of the main filament, akin to the formation of “apokamp” observed in pulsed-periodic nanosecond discharges. A quantitative characterization of the instability is provided, and potential mechanisms driving the flow are discussed.