Measurement of the plasma electron density and temperature from Stark-broadened Hβ and Hγ emission profiles

Abstract

Optical emission spectroscopy of the hydrogen Balmer β and Balmer γ emission profiles in an N$_{2}$–H$_{2}$ mixture plasma is carried out to investigate their line shapes and intensities as functions of the discharge parameters such as gas composition (20–80% H2), input electrical power (200–400 W) and filling pressure (3–7 mbar). The Stark widths (full widths at half-maximum) of the Hβ and Hγ emission profiles, after unfolding the contribution originating from other broadening mechanisms, is used to determine the electron density and temperature. This method offers the possibility of determining the plasma electron density and temperature in a rapid and easy way that may be applicable for a large number of industrial applications.