A5029666761- High-pressure geophysics and materials
- Atomic and Molecular Physics
- Advanced Chemical Physics Studies
- Laser-induced spectroscopy and plasma
- Theoretical and Computational Physics
- Astro and Planetary Science
- Dust and Plasma Wave Phenomena
- Plasma Diagnostics and Applications
- Quantum, superfluid, helium dynamics
- Nuclear physics research studies
- Phase Equilibria and Thermodynamics
- Muon and positron interactions and applications
- Cold Atom Physics and Bose-Einstein Condensates
- Machine Learning in Materials Science
- X-ray Spectroscopy and Fluorescence Analysis
- Diamond and Carbon-based Materials Research
- Material Dynamics and Properties
- Physics of Superconductivity and Magnetism
- Solar and Space Plasma Dynamics
- Force Microscopy Techniques and Applications
- Mass Spectrometry Techniques and Applications
- Astrophysics and Star Formation Studies
- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- nanoparticles nucleation surface interactions
Los Alamos National Laboratory
2016-2025
Computational Physics (United States)
2023
The University of Texas at Austin
2022
Pacific Northwest National Laboratory
2022
University of Rochester
2022
Energetics (United States)
2022
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2010
CEA DAM Île-de-France
2010
Queen's University Belfast
2005-2008
The results of a numerical implementation the recent average atom model including ion-ion correlations Starrett and Saumon [Phys. Rev. E 85, 026403 (2012)] are presented. solution is obtained by coupling an to two-component plasma electrons ions. two models solved self-consistently given in form pair distribution functions. Ion-ion functions for hydrogen, carbon, aluminum, iron compared quantum Thomas-Fermi molecular dynamics simulations as well path-integral Monte Carlo calculations good...
The aim of this paper is to provide experimental data on various expanded elements in the warm dense matter regime. experiments were done facility “enceinte à plasma isochore” and are evaluated through a thorough comparison with ab initio calculations, average-atom codes, chemical models. This allows for evaluation temperatures that not accessible measurements permits building useful tables gathering energy, pressure, conductivity, temperatures. We summarize performed aluminum (0.1 0.3...
We present a theoretical model that allows fast and accurate evaluation of ionic transport properties realistic plasmas spanning from warm dense to hot dilute conditions, including mixtures. This is achieved by combining recent kinetic theory based on effective interaction potentials with for the equilibrium radial density distribution an average atom integral equations fluids. The should find broad use in applications where nonideal plasma conditions are traversed, inertial confinement...
The Kubo-Greenwood formulation for calculation of optical conductivities with an average atom model is extended to calculate thermal conductivities. method applied species and conditions interest inertial confinement fusion. For the mixed studied, partial pressure mixing rule used. Results including pressures, dc, are compared ab initio calculations. Agreement pressures good, both pure species. conductivities, it found that ad hoc renormalization line broadening, described in text, gives...
We present calculations of x-ray scattering spectra based on ionic and electronic structure factors that are computed from a new model for warm dense matter. In this model, which has no free parameters, the is determined consistently with bound states. The spectrum thus fully by plasma temperature, density nuclear charge, experimental parameters. combined matter theory validated against an experiment room-temperature, solid beryllium. It then applied to experiments beryllium aluminum....
An approach to simulating warm and hot dense matter that combines density-functional-theory-based calculations of the electronic structure classical molecular dynamics simulations with pair interaction potentials is presented. The method, which we call pseudoatom dynamics, can be applied single-component or multicomponent plasmas. It gives equation state self-diffusion coefficients an accuracy comparable orbital-free but computationally much more efficient.
Accurate modeling of warm and hot dense matter is challenging in part due to the multitude excited states that must be considered. Here, we present a variational framework models these states. In this an state defined by set effective one-electron occupation factors, corresponding energy one-body with exchange correlation term. The applied atom-in-plasma model (a generalization so-called average atom model). Comparisons density functional theory based generally reveal good agreement...
ABSTRACT Under the extreme conditions found in small stars, where electron degeneracy and Coulomb coupling are significant, accurate modeling of Thomson scattering is crucial for determining opacity, a primary quantity stellar energy transport. We use hypernetted‐chain calculations, incorporating quantum pseudopotentials electron‐exchange effects to obtain electron–electron static structure factor calculate transport cross‐section prevailing interior stars. These results compared those from...
An average atom model for dense ionized fluids that includes ion correlations is presented. The assumes spherical symmetry and based on density functional theory, the integral equations uniform fluids, a variational principle applied to grand potential. Starting from theory mixture of classical ions quantum mechanical electrons, an approximate potential developed, with external field being created by central nucleus fixed at origin. Minimization this respect electron densities carried out,...
In Starrett and Saumon [Phys. Rev. E 87, 013104 (2013)] a model for the calculation of electronic ionic structures warm hot dense matter was described validated. that structure one "atom" in plasma is determined using density functional theory based average-atom (AA) model, by coupling AA to integral equations governing fluid structure. That plasmas with nuclear species only. Here we extend it treat many species, i.e. mixtures, apply carbon-hydrogen mixture relevant inertial confinement...
We present an approximation for calculating the equation of state (EOS) warm and hot dense matter that is built on previously published pseudoatom molecular dynamics (PAMD) model plasmas [Starrett et al., Phys. Rev. E 91, 013104 (2015)]. While EOS calculation with PAMD was limited to orbital-free density functional theory (DFT), new presented here allows a Kohn-Sham DFT treatment electrons. The resulting thus includes quantum mechanical electrons self-consistent ionic structure, while...
We present a new model of electron transport in warm and hot dense plasmas which combines the quantum Landau-Fokker-Planck equation with concept mean-force scattering. obtain electrical thermal conductivities across several orders magnitude temperature, from matter conditions to hot, nondegenerate plasma conditions, including challenging crossover regime between two. The small-angle approximation characteristic Fokker-Planck collision theories is mitigated good effect by construction...
We present experimental results on pressure and resistivity expanded nickel at a density of $0.1\text{ }\text{g}/{\text{cm}}^{3}$ temperature few eV. These data, corresponding to the warm dense matter regime, are used benchmark different theoretical approaches. A comparison is presented between fully three-dimensional quantum molecular dynamics (QMD) methods, based functional theory, with average atom that essentially one dimensional. In this regime evaluation thermodynamic properties as...
Dense plasmas occur in stars, giant planets, and inertial fusion experiments. Accurate modeling of the electronic structure these allows for prediction material properties that can turn be used to simulate astrophysical objects terrestrial But them remains a challenge. Here we explore Korringa-Kohn-Rostoker Green's function (KKR-GF) method this purpose. We find it is able predict equation state good agreement with other state-of-the-art methods, where they are accurate viable. In addition,...
Abstract The diffusion of elements is a key process in understanding the unusual surface composition white dwarfs and their spectral evolution. coefficients Paquette et al. have been widely used to model dwarfs. We perform new calculations interdiffusion ionic thermal with (1) more advanced that uses recent modification calculation collision integrals suitable for partially ionized, degenerate, moderately coupled plasma (2) classical molecular dynamics. are evaluated silicon calcium dwarf...
In a dense plasma environment, the energy levels of an ion shift relative to isolated values. This is reflected in optical spectrum and can be measured in, for example, emission experiments. this work we use recently developed method modeling electronic states warm matter predict these level energies. model excited state energies are calculated directly by enforcing constrained one-electron occupation factors, thus allowing calculation specific transition ionization includes effects...
The impulse approximation is used to calculate cross sections for fragmentation of $\mathrm{Ps}(1s)$ in collision with He, Ne, Ar, Kr, and Xe. Triple, double, single, total are evaluated. Reasonably good agreement found the measurements Armitage et al. [Phys. Rev. Lett. 89, 173402 (2002)] on $\mathrm{Ps}(1s)+\mathrm{He}(1^{1}S)$ scattering. These absolute comprise Ps ionization section differential respect longitudinal energy ejected positron. Characteristics free electron positron...