Measurement of electron temperature and density of atmospheric-pressure non-equilibrium argon plasma examined with optical emission spectroscopy

The electron temperature T-e and density N-e of atmospheric-pressure non-equilibrium dielectric barrier discharge argon (Ar) plasma are measured with optical emission spectroscopy. Continuum emission due to bremsstrahlung is applied to the analysis of the electron temperature and density with the spectrometric system in the visible wavelength range calibrated absolutely. The assumption of the Maxwellian electron energy distribution function (EEDF) results in T-e 0.29 eV and N-e 1.1 x 10(16) cm(-3), whereas the Druyvesteyn EEDF leads to the result T-e 0.79 eV and N-e 1.4 x 10(14) cm(-3). To confirm the validity of these values, several line intensities of the excited states of the Ar atom are observed experimentally and compared with the theoretical population densities calculated by the Ar collisional-radiative (CR) model that includes atomic collisional processes. It is confirmed that the order of the observed excited-state number densities agrees well with that calculated numerically by the CR model with the Druyvesteyn EEDF, while the Maxwellian EEDF gives poor results. (c) 2021 The Japan Society of Applied Physics

Automated summary

The electron temperature and density of atmospheric-pressure non-equilibrium dielectric barrier discharge argon plasma were measured using optical emission spectroscopy. The results show that the electron energy distribution function significantly affects the accuracy of the measurements, with the Druyvesteyn EEDF producing better results compared to the Maxwellian EEDF. Additionally, experimental observations of excited state line intensities of the Ar atom confirmed the validity of the values obtained from the CR model calculations.