Development of a cathode-directed streamer discharge in air at different pressures: Experiment and comparison with direct numerical simulation

TLDR

The study investigates how discharge branching patterns change with pressure in cathode‑directed streamer discharges. The authors conduct experiments in synthetic air from 760 to 300 torr and compare the results with 2D hydrodynamic simulations of the discharge. Experimental results show that the electric field at the streamer head is largely pressure‑independent, while electron density drops by an order of magnitude and chemical production scales at least with the inverse square of pressure; measured anode current, streamer velocity, and channel diameter agree with the 2D hydrodynamic predictions.

Abstract

The results are given of an experimental investigation of a cathode-directed streamer discharge in synthetic air in the pressure range from 760 to 300 torr and their comparison with the results of direct numerical simulation in a 2D hydrodynamic approximation. The pattern of discharge branching upon variation of pressure is investigated experimentally. The results are given of comparison of the predicted and measured values of anode current, streamer propagation velocity, and channel diameter. It has been demonstrated that the electric field in the streamer head is hardly affected by the pressure decrease, while the electron concentration decreases with pressure by an order of magnitude. At the same time, production of chemical species in a cathode-directed streamer discharge varies at a rate of at least the second power of inverse pressure.