Optical Observation of Nitrogen Propagation in Argon Plasma

While the gas flow patterns in reactors can be visualized using models, it has proven that it is difficult to measure them. This paper shows that the gas flow pattern for pulsed injection of nitrogen gas into argon plasma can be readily seen in the optical emission intensity. As N₂ enters the Ar plasma, N₂ molecules cause increased optical emission intensity by the Penning effect. This allows one to measure the N₂ propagation. In this paper, we present the pictures with the measurement details and analysis.