Numerical simulation for the production of chemically active species in primary and secondary streamers in atmospheric-pressure dry air

Abstract

Production of chemically active species in primary and secondary streamers is investigated using a two-dimensional axisymmetric numerical simulation model. The production processes of N2(v = 1), O(3P) and N(4S), which each have different threshold energies, are simulated using experimentally obtained pulsed voltages with peak values, Vpeak, of 18, 24 and 30 kV in dry air at atmospheric pressure. As Vpeak increases, the simulated length of the secondary streamer increases, although there is little change in the primary streamer characteristics. This means that the ratio of the secondary streamer phase to the primary streamer phase increases for increasing Vpeak. The simulated results show that as Vpeak increases, the energy efficiency of O(3P) production increases and that of N2(v = 1) production decreases. On the other hand, the energy efficiency of N(4S) production has reduced dependence on Vpeak. These characteristics can be explained by the spatiotemporal variations of the reduced electric field in the primary and secondary streamer.