Using the Stark Broadening of the H_α, H_β and H_γ Lines for the Measurement of Electron Density and Temperature in a Plasma at Atmospheric Pressure

Abstract

For a microwave plasma at atmospheric pressure the use of the Stark broadening of the H_α, H_β and H_γ lines to determine the electron density and temperature is reported. Knowing the values of these plasma parameters is important because the electrons (density) and their energy (temperature) control the internal kinetics in the discharge. We found that the use of the Gigosos–Cardeñoso model permitted us to obtain the same value of the electron density from the Stark broadening of the three Balmer lines. The dependence of the Stark broadening on the electron density and temperature for H_α, H_β and H_γ lines has permitted the application of an intersection method to try finding the values of the electron density and temperature simultaneously. The results have shown the possibility of estimating the electron density with an uncertainty of under 10% by using this intersection method, without knowing the accurate value of the electron temperature. In the case of the electron temperature the uncertainty was 40%, which seems to indicate that this method is not appropriate for the determination of this plasma parameter.