High-Voltage Nanosecond Discharge: Dynamics of the Initial-Stage Breakdown in a Highly Inhomogeneous Electric Field

We present the results of simulation of the initial breakdown stage of a high-voltage nanosecond discharge (HVND) in air at atmospheric pressure in a gap with a sharply inhomogeneous electric-field distribution. The simulation was based on an established relation between the discharge-gap capacitance upon streamer formation, the experimentally detected dynamic displacement current, and the voltage across the gap. The dynamics of the streamer shape at the discharge stage was recorded with sub-nanosecond resolution using a four-channel ICCD camera, simultaneously with the electric characteristics of the discharge. The time dependences of the radius, position, and propagation velocity of the streamer front in both axial and radial directions at the initial breakdown stage are obtained.