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Comparative Study of Electron Bremsstrahlung in Various High ρ - T Potentials

Published online by Cambridge University Press:  12 April 2016

M. Lamoureux ,
R. Cauble ,
L. Kim ,
F. Perrot  and
R.H. Pratt
M. Lamoureux
Affiliation:
LSAI, University of Paris-Sud 91405 Orsay, France
R. Cauble
Affiliation:
Berkeley Research Associates Springfield, VA 22151, USA
L. Kim
Affiliation:
University of Pittsburgh Pittsburgh, PA 15260, USA
F. Perrot
Affiliation:
CEA Limeil 94190 Villeneuve St. Georges, France
R.H. Pratt
Affiliation:
University of Pittsburgh Pittsburgh, PA 15260, USA

Extract

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In order to calculate bremsstrahlung cross sections in plasmas, an atomic potential which includes the effects of the surrounding plasma is required. For the high ρ - T conditions we are considering (ne = 1025 cm−3, T = 500 ev), plasma correlative effects are important. In these strongly coupled plasmas, the Debye-Huckel potential is irrelevant and not considered here. The statistical Thomas-Fermi (TF) potential (Feynmann, Metropolis, and Teller, 1949) is known to be correct at very high densities but does not contain correlation information. A semiclassical treatment of correlations that accurately reproduces results of numerical simulations of strongly coupled plasmas is the hypernetted chain (HNC) approximation to the hierarchy of equations describing density distributions (Hansen and McDonald, 1981). The method generates many-body distributions using an analytic two-body interaction that successfully approximates quantum effects at short distances. These distributions are used in the Poisson equation to find the effective potential (Cauble, Blaha, and Davis, 1984). An alternative method (Gupta and Rajagopal, 1982) of including correlations is to treat them in a quantum mechanical manner, taking into account ion correlations as well as electron exchange and correlation; this is done in density functional theory (DFT), where electron wavefunctions and the effective potential which is used here are obtained self-consistently (Dharma-wardana and Perrot, 1982; Perrot and Dharma-wardana, 1984). Comparison of these methods can be found elsewhere (Cauble, Gupta, and Davis, 1984). These potentials for aluminum at 1025 cm−3 and 500 eV are displayed in Fig. 1.

Type
Session 6. Poster Papers
Information
International Astronomical Union Colloquium , Volume 86: Eighth International Colloquium on Ultraviolet and X-ray Spectroscopy of Astrophysical and Laboratory Plasmas , 1984 , pp. 187 - 190
Copyright
Copyright © Naval Research Laboratory 1984. Publication courtesy of the Naval Research Laboratory, Washington, DC.

References

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