Time-resolved study of the electron temperature and number density of argon metastable atoms in argon-based dielectric barrier discharges

A combination of optical emission spectroscopy and collisional-radiative modelling is used to determine the time-resolved electron temperature (assuming Maxwellian electron energy distribution function) and number density of Ar 1s states in atmospheric pressure Ar-based dielectric barrier discharges in presence of either NH3 or ethyl lactate. In both cases, T e values were higher early in the discharge cycle (around 0.8 eV), decreased down to about 0.35 eV with the rise of the discharge current, and then remained fairly constant during discharge extinction. The opposite behaviour was observed for Ar 1s states, with cycle-averaged values in the 1017 m−3 range. Based on these findings, a link was established between the discharge ionization kinetics (and thus the electron temperature) and the number density of Ar 1s state.