Numerical study on pulsed-DC atmospheric-pressure plasma jet

A numerical and experimental study of plasma jet propagation in low temperature, atmospheric-pressure, helium jet in ambient air is presented. A self-consistent, multi-species, two-dimensional axially symmetric plasma model with detailed finite-rate chemistry of helium-air mixture composition is used to provide insights into the propagation of the plasma jet. The obtained simulation results suggest the sheath forms near the dielectric tube inner surface and shields the plasma channel from the tube surface. The strong electric field at the edge of dielectric field enhances the ionization in the air mixing layer, therefore the streamer head changes into the ring shape when the streamer runs out of the tube. The avalanche to streamer transition is the main mechanism of the streamer advancement. Penning ionization dominated the ionization reactions and increased the electric conductivity of plasma channel. The simulation results are supported by the experiment observations with the similar discharge conditions.