Greifswald 2009 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 18: Poster: Theorie/Modellierung
P 18.9: Poster
Mittwoch, 1. April 2009, 17:30–19:30, Foyer des IfP
Pressure broadening of Lyman-Lines in Dense Li2+ Plasmas — •Sonja Lorenzen1, August Wierling1, Heidi Reinholz1,2, and Gerd Röpke1 — 1Institut für Physik, Universität Rostock, 18051 Rostock, Germany — 2University of Western Australia, Nedlands, WA 6009, Australia
Pressure broadening of Lyman-lines of hydrogen-like lithium is studied using a quantum statistical approach to the line shape in dense plasmas. We report line widths (FWHM) and shifts for Lyman-α, -β, and -γ in a wide range of densities (ne=1024−1028 m−3) at temperatures relevant for laser-produced lithium plasmas (T=105 K). We discuss the effect of different ionic microfield distributions and estimate the influence of ion dynamics. Special care is taken to account for strong collisions. The results are applied to measured spectra of lithium irradiated by a nanosecond laser pulse of moderate intensities ( I ≈ 1011−1013 W/cm2), see G. Schriever et al. [Applied Optics 37, 1243 (1998), J. Appl. Phys. 83, 4566 (1998)]. By matching synthetic spectra to the experimental ones, density and temperature conditions are inferred assuming the model of a one-dimensional uniform plasma slab. Self-absorption is accounted for and found to be important for Lyman-α. In this way, experimental spectra are overall reproduced. To describe remaining deviations in the line wings, it is essential to use a multilayer model adapted to density and temperature profiles from hydrodynamic expansion codes.