Study of the dynamics of a barrier hollow-cathode discharge using a broadened Hα line

Abstract

Spatially and temporally resolved emission spectroscopy of an excessively broadened Balmer alpha line was used for characterization of low-pressure barrier hollow-cathode discharge. The line profile was divided into segments according to excitation mechanism for the separate monitoring of electrons and fast atom population (kinetic energy ∼200 eV). Kinetic energies of excited fast atoms were also analysed due to their connection to the hydrogen ions. It was found that the evolution of the electric field configuration and change in the gap potential, induced by space charge formation, is instantaneously reflected in line segment intensity and spatial distribution. These results concur with the known models of pre-breakdown and breakdown processes in a hollow cathode. Our results suggest the use of broadened Hα lines for monitoring of discharge breakdown and development. © 2014 IOP Publishing Ltd.