Atome moyen variationnel dans les plasmas quantiques

Abstract : Calculations of the radiative properties of dense plasmas are usually based on the concept of an atom in a plasma. Such a concept is often used in average-atom models which constitute a good starting point for more sophisticated statistical approaches. Average-atom models are also directly useful in the calculation of the equation of state and of some transport coefficients. Since Feynman, Metropolis and Teller application of the Thomas-Fermi model to dense plasmas, all attempts to construct a quantum extension of the model have led to some thermodynamic inconsistencies. This work concerns a variational Average-Atom model of dense plasmas. Contrary to other models, this one gives access to the thermodynamic equilibrium and respects the virial theorem. In order to resolve the model's equations, a numerical code called VAAQP (Variational Average-Atom in Quantum Plasmas) was written. In particular, it allows us to calculate the equation of state. After a description of other models, we outline the variational model formalism in the framework of the Thomas-Fermi theory, of the non-relativistic quantum mechanics, and of the relativistic quantum mechanics. It is then shown that the variational model fulfills the virial theorem and the thermodynamic inconsistencies of the other models are explained. The numerical methods which constitute the basis of the VAAQP code are described. Applications of the variational model to equation of state computations are presented and compared to results from other models, such as INFERNO. Comparisons to experiments on the Hugoniot shock adiabats are also shown.
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Contributor : Robin Piron <>
Submitted on : Wednesday, January 13, 2010 - 9:07:38 AM
Last modification on : Wednesday, January 23, 2019 - 2:39:05 PM
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Robin Piron. Atome moyen variationnel dans les plasmas quantiques. Physique [physics]. Commissariat à l'Energie Atomique, 2009. Français. ⟨tel-00446558⟩

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