Excitation temperatures of atmospheric argon in dielectric barrier discharges

A method for the determination of excitation temperatures based on optical emission spectroscopy and Fermi-Dirac distribution was set up and experiments were performed on atmospheric argon dielectric barrier discharges. Local thermodynamic equilibrium was proved to exist in the discharge and the validity of Boltzmann distribution is discussed. The main aim of this paper is to obtain the temperatures of atmospheric Ar II as a function of the discharge voltage, discharge frequency, argon flow rate and the argon fraction. It was found that the excitation temperatures are in the range 3800-4950 K. Besides, an increase in the argon flow rate resulting in a slight growth of the temperature and the add-in of air leading to the decrease in temperature was observed.