Spectroscopic diagnosis of an atmospheric-pressure waveguide-based microwave N2–Ar plasma torch

An atmospheric-pressure N 2 –Ar plasma is investigated by means of optical emission spectroscopic diagnosis concerning the variation of its fundamental parameters, electron density and plasma temperature, and concentrations of ionized molecular nitrogen, atomic nitrogen, and excited argon with the tuning variables, such as the input power and the ratio of N 2 in N 2 –Ar mixture gas, in the discharge region of the plasma torch. Moreover, qualitative discussions are delivered with respect to the mechanisms for nitrogen dissociation and influence of the Ar component on the N 2 plasma discharge at atmospheric pressure.