Coaxial Diffuse Discharges Driven by Repetitive Nanosecond Pulses at Different Air Pressures

Images of diffuse discharges with a coaxial configuration in a 5-cm gap under different conditions are presented to illustrate the characteristics of large-area diffuse discharges. One ns-pulse generator with a rise time of 70 ns and a duration of 100 ns was used. Results show that the diffuse discharge is composed of plasma channels that start from bright spots on the inner electrode and expand in the direction to the outer electrode. The number of the bright spots increases with the decrease of gas pressure. Furthermore, comparing with the high repetition rate, the plasma channels are more likely to overlap with each other at low repetition rate.