Diffusion in a Microwave Plasma in the Presence of Turbulent Flow

Microwave breakdown and diffusion in a weakly ionized microwave plasma was studied in the presence of turbulent flow of the neutral gas. Breakdown was produced by pulsed microwaves in helium, hydrogen, nitrogen, and argon in a tube placed along the E field of an S-band waveguide. The microwave power at breakdown (or at extinction) is a measure of the diffusion rate of the charged particles to the walls of the tube. This power was measured as a function of flow rate of the neutral gas. The minimum microwave breakdown power exhibits a sharp upward break when turbulent flow sets in.