Spectroscopic study of a stationary surface-wave sustained argon plasma column at atmospheric pressure

A spectroscopic study of an argon surface wave plasma column at atmospheric pressure under steady-state conditions shows that we are dealing with a two-temperature (2T) discharge whose excitation kinetics are controlled by electron collisions (electron excitation kinetic plasma). A partial local Saha equilibrium in the excitation space is reached from which the 4s and 4p levels are excluded. The absorbed high frequency (HF) power per electron for the maintenance of the discharge (the parameter θ) was found to be a magnitude increasing with the electron density, contrary to what occurs at low pressure. Modifying the work conditions, such as gas flow and HF power, we obtained plasmas that are similar in structure when the end of the plasma is used as a reference position.