Biomedical subjects

G Faussurier

Publications and source records attributed to G Faussurier.

4 recordsLinked to original sources

PubMed2002

Combined pressure and electrical-resistivity measurements of warm dense aluminum and titanium plasmas.

Electrical resistivity, pressure, and internal energy variation of warm dense correlated titanium (density 0.2 g/cm(3)) and aluminum (density 0.1 g/cm(3)) plasmas are measured using a homogeneous and thermally equilibrated media produced inside an isochoric closed-vessel plasma. These data are compared to detailed calculations based on the density functional theory. In the studied temperature range (15,000-30,000 K), it appears that both exchange-correlation and ion-ion interaction treatments are of great importance to calculate accurate theoretical values.

Journal Article↗

PubMed2001

Generalization of super-transition-array methods to hot dense plasmas by using optimum independent particle reference systems.

The computation of superconfiguration partition functions relies upon independent electron statistics, with electron-electron contributions included as an average first-order correction factor. The decomposition into a first-order correction and reference independent electron system has degrees of freedom not exploited by current methods. We present a derivation for the conventional choice of decomposition and propose a different method for obtaining an optimal decomposition for each superconfiguration. This constitutes an alternative procedure to recomputing self-consistent fields for the refinement of superconfiguration partition functions. Numerical results are presented and discussed.

Journal Article↗

PubMed2001

Nonlocal thermodynamic equilibrium self-consistent average-atom model for plasma physics.

A time-dependent collisional-radiative average-atom model is presented to study statistical properties of highly charged ion plasmas in off-equilibrium conditions. The time evolution of electron populations and the electron covariance matrix is obtained as approximate solutions of a master equation. Atomic structure is described either with a screened-hydrogenic model including l splitting, or by calculating one-electron states in a self-consistent average-atom potential. Collisional and radiative excitation/deexcitation and ionization/recombination rates, as well as autoionization and dielectronic recombination rates, are formulated within the average-configuration framework. Local thermodynamic equilibrium is obtained as a specific steady-state solution. The influence of atomic structure and the role of autoionization and dielectronic recombination processes are studied by calculating steady-state average ionization and ionization variance of hot plasmas with or without radiation field.

Journal Article↗

PubMed1999

Superconfiguration accounting approach versus average-atom model in local-thermodynamic-equilibrium highly ionized plasmas.

Statistical methods of describing and simulating complex ionized plasmas requires the development of reliable and computationally tractable models. In that spirit, we propose the screened-hydrogenic average atom, augmented with corrections resulting from fluctuations of the occupation probabilities around the mean-field equilibrium, as an approximation to calculate the grand potential and related statistical properties. Our main objective is to check the validity of this approach by comparing its predictions with those given by the superconfiguration accounting method. The latter is well-suited to this purpose. In effect, this method makes it possible to go beyond the mean-field model by using nonperturbative, analytic, and systematic techniques. Besides, it allows us to establish the relationship between the detailed configuration accounting and the average-atom methods. To our knowledge, this is the first time that the superconfiguration description has been used in this context. Finally, this study is also the occasion for presenting a powerful technique from analytic number theory to calculate superconfiguration averaged quantities.

Journal Article↗