Electron density and temperature measurement method by using emission spectroscopy in atmospheric pressure nonequilibrium nitrogen plasmas

Abstract

A novel spectroscopic method is proposed for the measurement of electron density and temperature in atmospheric pressure dielectric barrier discharges using nitrogen gas. Simplified collisional-radiative models for the electronic and the vibrational states yield two separate continuity equations as a function of the electron density and the temperature with the coefficients expressed in terms of rotational temperature, vibrational temperature, and emission intensity ratio between the first positive system and the second positive system of nitrogen molecules. The electron density and the temperature in nonequilibrium atmospheric pressure plasmas can be determined by solving the continuity equations with the coefficients estimated from the spectroscopic measurements. It was confirmed by applying to a high power dielectric barrier discharge, where the measured plasma parameters were in good agreement with the estimation by using the electron conductivity of the discharge.