Measurements of the Stark Broadening of Two Neutral Helium Lines in a Plasma

Greig, J.R. and Lim, C.P. and Moo-Young, G.A. and Palumbo, G. and Griem, Hans R. (1968) Measurements of the Stark Broadening of Two Neutral Helium Lines in a Plasma. Physical Review, 172 (1). pp. 148-153. ISSN 0031-899X

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Official URL: https://doi.org/10.1103/PhysRev.172.148

Abstract

A detailed study has been made of the broadening of the lines λ3889 (width only) and λ5016 (shift and width) of neutral helium in the plasma produced in an electromagnetically driven T tube operating in helium-hydrogen gas mixtures. The electron density in the plasma was found from the broadening of Hβ, while the temperature was determined from the ratio of the intensity of Hβ to that of the underlying continuum. Temperatures were in the range 20 000-30 000°K; electron densities varied from 1016 to 6×1017 cm-3. The broadening of the line λ3889 was found to increase linearly with electron density; and it compared well with calculations based on the generalized impact theory, except for (constant) correction factors ranging from about 0.9 to 1.0 (depending on which of the various calculations is referred to). For the line λ5016, neither of the previous calculations, nor a correction discussed here, predicts either the width or the shift variations satisfactorily; all the calculations give significantly wider lines above electron densities of 1017 cm-3 than are found experimentally. Also, as the electron density increases, the calculated shifts all become increasingly larger than those found experimentally. However, at the low densities most deviations are small (20%). © 1968 The American Physical Society.

Item Type: Article
Additional Information: Lim, C.P. Department of Physics, University of Malaya, Kuala Lumpur, Malaysia.
Uncontrolled Keywords: Measurements; stark broadening; neutral helium lines; plasma
Subjects: Q Science > Q Science (General)
Q Science > QC Physics
Divisions: Faculty of Science > Dept of Physics
Depositing User: Ms. Juhaida Abd Rahim
Date Deposited: 02 Nov 2020 01:40
Last Modified: 02 Nov 2020 01:40
URI: http://eprints.um.edu.my/id/eprint/25594

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