Simulation of the Streamer Propagation in a Small Region with Monte Carlo Photoionization

Abstract

The results of a centimeter-scale study of the streamer development in air are presented. The numerical simulation is performed using the open-source Afivo-streamer code. Photoionization, which significantly contributes to streamer branching, is taken into account using a Monte Carlo approach. The pressure varies in the range of 500–1000 mbar, and the background electric field is 6–15 kV/cm. The streamer development dynamics is studied for a single seed and two spatially separated seeds located parallel to each other with a vertical offset. Electron density distributions show that the increase in pressure and background field leads to rapid and complex branching, increase in the electron density in streamer channels, and merging of adjacent structures. The distributions of the \({\text{N}}_{2}^{ + }\) ion density, electric field are plotted for the case with two seeds, and cross slices are performed in the region of channel merging. This has made it possible to establish that the electron density maxima correspond to the electric field minima. The simulation results are consistent with experimental data obtained for an extended high-voltage atmospheric discharge.