Stark broadening tables for the helium I 492.2 line

Application to weakly coupled plasma diagnostics^⋆

¹ Departamento de ÓpticaUniversidad de Valladolid, 44071 Valladolid, Spain
e-mail: gigosos@coyanza.opt.cie.uva.es
² Departamento de Física Aplicada, Universidad de Valladolid, 44071 Valladolid, Spain
e-mail: manuelgd@termo.uva.es

Received: 28 February 2012
Accepted: 23 April 2012

Abstract

Context. We studied the Stark broadening of the He I 492.2 nm line, which is sometimes used for plasma diagnostics or to obtain information on different stellar parameters.

Aims. The final aim of this study is to obtain tables of lines shapes as well as the relationships between different line parameters and the plasma electron density, temperature, or composition. The tables of profiles and the mathematical expressions obtained will be used in plasma diagnostics.

Methods. We performed computer simulations and used a physical model that considers a weakly coupled plasma. Our computer simulations naturally take into account ion dynamical effects, which has permitted us to study the influence on the line shapes of imbalances in the plasma caused by different electron and gas temperatures.

Results. Our computer simulations considered electron densities between 10¹⁹ and 10²⁴ m^-3, electron temperatures between 5000 and 40 000 K, and plasmas of different compositions. The dependences obtained in the simulations for the line width, the ratio of intensities between the allowed and the forbidden components, or the distances between those components’ peaks on the plasma conditions are shown and compared with experimental data. Numerical expressions for the line width and for the peak distances against the electron density were obtained from the simulation results and can be applied to obtain the electron density from experimental results. Full line profile tables are also supplied for use in plasma diagnostics.