A contribution to spectroscopic diagnostics and cathode sheath modeling of micro-hollow gas discharge in argon

摘要

In this paper, the hydrogen Balmer beta line shape from a micro-hollow gas discharge (MHGD) in argon with traces of hydrogen is used for simultaneous diagnostics of plasma and cathode sheath (CS) parameters. For this purpose, a simple model of relevant processes responsible for the line broadening is introduced and applied to the Balmer beta profile recorded from a MHGD generated in the microhole (diameter 100 fim at narrow side and 130 /an at wider side) of a gold-alumina-gold sandwich in the pressure range (100-900 mbar). The electron number density Ne in the range (0.4-4.5) x 1020 m~3 is determined from the width of the central part of the Balmer beta line profile, while, from the extended wings of the Balmer beta profile, induced by dc Stark effect, the next three parameters are determined: the average value Ea of electric field strength in the CS in the range (16-95 kV/cm), the electric field strength Eo at the cathode surface in the range (32-190 kV/cm), and the CS thickness zg in the range (18-70 fim). All four MHGD parameters, Nf, Ea, £o, and zg, compare reasonably well with results of the modeling experiment by M. J. Kushner [J. Phys. D: Appl. Phys. 38, 1633 (2005)]. The results for Ne are compared with other emission experiments.