The Free-Free Opacity in Warm, Dense, and Weakly Ionized Helium
Abstract
We investigate the ionization and the opacity of warm, dense helium under conditions found in the atmospheres of cool white dwarf stars. Our particular interest is in densities up to and temperatures from 1000K to 10000K. For these physical conditions various approaches for modeling the ionization equilibrium predict ionization fractions that differ by orders of magnitudes. Furthermore, estimates of the density at which helium pressure-ionizes vary from to . In this context, the value of the electron-atom inverse bremsstrahlung absorption is highly uncertain. We present new results obtained from a non-ideal chemical model for the ionization equilibrium, from Quantum Molecular Dynamics (QMD) simulations, and from the analysis of experimental data to better understand the ionization fraction in fluid helium in the weak ionization limit.
Cite
@article{arxiv.cond-mat/0511400,
title = {The Free-Free Opacity in Warm, Dense, and Weakly Ionized Helium},
author = {P. M. Kowalski and S. Mazevet and D. Saumon},
journal= {arXiv preprint arXiv:cond-mat/0511400},
year = {2009}
}
Comments
4 pages, 3 figures, 1 table. Accepted for publication in the Proceedings of the 14th APS Topical Conference on Shock Compression of Condensed Matter, Baltimore, MD