Modelling of plasma bullet propagation along a helium jet in ambient air

The results of simulation of positive streamer propagation along a helium jet in ambient air are presented. A two-dimensional axially symmetric streamer model, accounting for variation of helium–air mixture composition in the jet, is used. The obtained distributions of plasma parameters have a ring-shaped structure, typical for plasma bullets. The calculated radial profiles of emitting nitrogen molecules agree with experimental data.