Low-Current Plasmatron as a Source of Nitrogen Oxide Molecules

This paper describes a usage of a low-current coaxial plasmatron for generation of nitrogen oxide molecules. Glow-type discharge in vortex air flow is sustained at an average current from 0.05 to 0.2 A that corresponds to an average discharge power from 65 to 160 W. The diameter of an exit nozzle of the plasmatron is of 0.5 cm, and the air flow is varied from 0.2 to 1.5 g/s. In such conditions, the discharge burns in nonsteady-state regime, when a sustainment of a plasma jet/plume and a plasma column in the plasmatron nozzle is accompanied by the spontaneous glow-to-spark transitions. Due to the special design of the anode nozzle, an efficient interaction of the air flow with the plasma plume and plasma column is provided. Typical contents of nitric monoxide in the output gas are of about several grams per cubic meter, and the cost for formation of one molecule is from 50 to 35 eV.