Self-pulsating streamer corona discharge under DC voltage

Streamer coronae in atmospheric pressure air produced using DC voltage present a self-pulsating behavior with current pulse widths on the order of hundreds of nanoseconds and pulsation frequencies on the order of kilohertz. These burst pulsations are controlled mostly by the electrostatics. For constant applied voltage, the burst is terminated by the near-electrode accumulation of space charge and the period between bursts is driven by the timescale for charge dispersion and electric field recovery. This differs from when using pulsed DC voltage: the streamer burst is ignited and quenched by the duration of the nanosecond-duration voltage pulses. In this contribution we explore the self-pulsating characteristics of streamer corona discharges under DC voltage. First, we exploit recent advancements in laser diagnostics to measure the electric field evolution during a streamer corona burst and its afterglow, using the electric field induced second harmonic generation (E-FISH) technique. Second, we explore the impact of enhancing charge transport through wind addition. Whereas wind velocity has a negligible impact at the timescale for streamer propagation, it significantly affects the transport of space charge and hence the pulse train behavior.