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New approximation for calculating free-free absorption in hot dense plasmas

Published online by Cambridge University Press:  09 March 2009

F. Perrot
F. Perrot
Affiliation:
Commissariat à l'Energie Atomique, Centre d'Etudes de Limeil-Valenton, 94195 Villeneuve St-Georges Cedex, France
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Abstract

We propose a model for calculating free-free absorption (inverse bremsstrahlung) in hot dense plasmas. This model writes the total Gaunt factor as the product of a static factor and a dynamic factor. The treatment of the static part is based on a relation between the absorption cross section and the elastic scattering cross section, which is exact for very low frequencies and becomes asymptotically correct when the Born approximation is valid. Generalizing this relation provides an expression of the absorption cross section Q(k, k′), which depends on the initial and final wave vectors k and k′, as an integral of a unique function S*(k). The calculation of nondiagonal matrix elements (k ≠ k′) is thus avoided. The analytic summation of the high angular momenta in the partial wave expansion of the cross section makes possible to apply the model in the limit of weak electron screening. The collective effects are accounted for in a dynamic Gaunt factor and in an index of refraction different from unity. Numerical results for the Gaunt factor in cesium are presented and discussed. An application to the mean opacities of carbon is also shown.

Type
Research Article
Information
Laser and Particle Beams , Volume 14 , Issue 4 , December 1996 , pp. 731 - 748
Copyright
Copyright © Cambridge University Press 1996

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References

REFERENCES

Armstrong, B.H. & Nicholls, R.W. 1972 Emission, Absorption and Transfer of Radiation in Heated Atmospheres (Pergamon, Oxford).Google Scholar
Ashkin, M. 1966 Phys. Rev. 141, 41.CrossRefGoogle Scholar
Camous, F. 1976 Centre d'Etudes de Limeil-Valenton Internal Report (unpublished).Google Scholar
Dawson, J. & Oberman, C. 1962 Phys. Fluids 5, 517.CrossRefGoogle Scholar
Evans, R. et al. 1973 The Properties of Liquid Metals (Wiley, New York).Google Scholar
Feng, I.J. et al. 1983 Phys. Rev. 27, 3209.CrossRefGoogle Scholar
Genot, E. 1988 Centre d'Etudes de Limeil-Valenton Internal Report (unpublished).Google Scholar
Gradsteyn, I.S. & Ryzhik, I.M. 1965 Table of Integrals, Series and Products (Academic, New York).Google Scholar
Griem, H. 1965 Plasma Spectroscopy (McGraw Hill, New York).Google Scholar
Grimaldi, F. et al. 1985 Phys. Rev. A 32, 1063.CrossRefGoogle Scholar
Johnston, T.W. & Dawson, J.M. 1973 Phys. Fluids 16, 722.CrossRefGoogle Scholar
Karzas, W.J. & Latter, R. 1961 The Astrophysical Journal (Suppl.) 55, 167.CrossRefGoogle Scholar
Kogan, V.I. & Kukushkin, A.B. 1984 Sov. Phys. JETP 60, 665.Google Scholar
Lamoureux, M. & Pratt, R.H. 1985 Radiative Properties of Hot Dense Matter, Davis, J. et al. , eds. (World Scientific, Singapore) p. 241.Google Scholar
March, N.H. & Tosi, M.P. 1984 Coulomb Liquids (Academic, London).Google Scholar
Perrot, F. & Dharma-Wardana, M.W.C. 1993 Phys. Rev. Lett. 71, 797.CrossRefGoogle Scholar
Pines, D. & Nozieres, P. 1966 The Theory of Quantum Liquids (Benjamin, New York).Google Scholar
Rickert, A. 1995 J. Quant. Spectrosc. Radiat. Transfer 54, 325.CrossRefGoogle Scholar
Rogers, F.J. & Iglesias, C.A. 1992 The Astrophysical Journal (Suppl.) 79, 507.CrossRefGoogle Scholar
Rozsnyai, B.F. 1979 J. Quant. Spectrosc. Radiat. Transfer 22, 337.CrossRefGoogle Scholar
Zangvill, A. & Liberman, D. 1984 Phys. Rev. B 17, L253.Google Scholar
Zangvill, A. & Soven, P. 1980 Phys. Rev. A 21, 1561.CrossRefGoogle Scholar