Diffuse discharge, runaway electron, and x-ray in atmospheric pressure air in an inhomogeneous electrical field in repetitive pulsed modes

This letter reports on experimental studies of a pulsed discharge in an inhomogeneous electric field at a pressure of 1 atm for varying voltage pulse parameters. The amplitude of voltage pulses applied to point-to-plane and point-to-point gaps was 12–140 kV and the full width at half maximum was 1–40 ns. It is shown that in a wide range of experimental conditions, a diffuse discharge is ignited due to preionization of the gap by runaway electrons and x-rays. With all gaps, the runaway electrons are produced in response to electric field amplification near the electrodes and in the gap.