Spectroscopic Characterization of Argon–Nitrogen Surface-Wave Discharges in Dielectric Tubes at Atmospheric Pressure

The influence of nitrogen addition (up to 10 %) to an argon surface-wave atmospheric-pressure discharge has been investigated by spectroscopic means. Nitrogen introduction results in a significant increase of gas temperature, from 2000 to 4000 K, and a drastic reduction of electron density, from 1014 to 1013 cm−3. These variations come along with the disappearance of the discharge contraction and the apparition of a diffuse, less bright zone (postdischarge) in the downstream zone. Modifications of the argon discharge kinetics leading to a significant decrease of the density of argon excited states due to the presence of nitrogen have been discussed to the light of the spectra emitted by the discharge and a simplified kinetic model, showing the relevance of argon species in Penning excitation and charge transfer reactions.