CALCULATED PLASMA PARAMETERS AND EXCITATION SPECTRA OF HIGH-PRESSURE HELIUM DISCHARGES

Abstract

A collisional-radiative model was used to study the kinetics of an atmospheric pressure helium discharge. The electron kinetics was obtained from a two-term solution of the Boltzmann equation with electron–electron collisions included. The distribution of the helium electronic excited states was compared to measured values and used to calculate excitation temperatures. The results show that a unique value of the excitation temperature cannot be used to characterize the whole electronic states distribution, because the plasma is not in local thermodynamical equilibrium under the conditions considered. Other calculated discharge parameters, such as the electron temperature, the maintenance electric field, the density of metastable atoms in the 2 3 S state, and the ion densities are presented and compared to experimental data when available.