Discrepancies between Thomson-light-scattering results and those obtained from E/N measurements in a helium glow discharge
Institut für Experimentalphysik V, Ruhr-Universität
Bochum, 44780 Bochum, FRG
Accepted: 14 December 1995
Thomson-light-scattering techniques are applied for the diagnostics of the positive column of a glow discharge in helium. Already the first measurements revealed interesting discrepancies between mean electron energies and densities obtained by light scattering and a standard technique. The light scattering temperatures were considerably lower than those obtained via measurements of the reduced axial electric field, and their pressure dependence shows the discrepancies to increase with dropping pressure. As a possible explanation the dominating influence of associative ionisation (AI) is suggested, as has been done already by Chegotov (Phys. Rev. E, 50 (1994) 480).
PACS: 52.25.-b – Plasma properties / 52.70.-m – Plasma diagnostic techniques and instrumentation / 52.80.-s – Electric discharges
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