Integral equation model for warm and hot dense mixtures

Starrett, C. E.; Saumon, D.; Daligault, Jérôme; Hamel, Sébastien

doi:10.1103/physreve.90.033110

Cited by 33 publications

(44 citation statements)

References 39 publications

(81 reference statements)

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“…As the electrons are confined to the WS sphere in IS-AA models, they cannot display pre-peaks due to transient covalent bonding as found in liquid carbon, hydrogen and other low-Z WDMs. This was confirmed by Starrett et al [55] for carbon for their AA model. The bonding occurs by an enhanced electron density in the inter-ionic region between two WS spheres, and this is not allowed in IS models.…”

Section: Details Of the Npa Model Andzsupporting

confidence: 76%

Isochoric, isobaric, and ultrafast conductivities of aluminum, lithium, and carbon in the warm dense matter regime

et al. 2017

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We study the conductivities σ of (i) the equilibrium isochoric state (σis), (ii) the equilibrium isobaric state (σ ib ), and also the (iii) non-equilibrium ultrafast matter (UFM) state (σ uf ) with the ion temperature Ti less than the the electron temperature Te. Aluminum, lithium and carbon are considered, being increasingly complex warm dense matter (WDM) systems, with carbon having transient covalent bonds. First-principles calculations, i.e., neutral-pseudoatom (NPA) calculations and density-functional theory (DFT) with molecular-dynamics (MD) simulations, are compared where possible with experimental data to characterize σic, σ ib and σ uf . The NPA σ ib are closest to the available experimental data when compared to results from DFT+MD, where simulations of about 64-125 atoms are typically used. The published conductivities for Li are reviewed and the value at a temperature of 4.5 eV is examined using supporting X-ray Thomson scattering calculations. A physical picture of the variations of σ with temperature and density applicable to these materials is given. The insensitivity of σ to Te below 10 eV for carbon, compared to Al and Li, is clarified.

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Section: Details Of the Npa Model Andzsupporting

confidence: 76%

Isochoric, isobaric, and ultrafast conductivities of aluminum, lithium, and carbon in the warm dense matter regime

et al. 2017

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“…2 Here we write the expression for plasmas with one nuclear species, the expression for mixtures is given in reference [24]. 3 For all PAMD and OFMD calculations carried out for this paper we have used the Dirac exchange functional [25] (see also [23]).…”

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confidence: 99%

Pseudoatom molecular dynamics

2015

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A new approach to simulating warm and hot dense matter that combines density functional theory based calculations of the electronic structure to classical molecular dynamics simulations with pair interaction potentials is presented. The new method, which we call pseudoatom molecular dynamics (PAMD), can be applied to single or multi-component plasmas. It gives equation of state and selfdiffusion coefficients with an accuracy comparable to ab-initio simulations but is computationally much more efficient.PACS numbers: 51.20.+d, 51.30.+i, 52.25.Kn, 52.65.Yy The challenge of accurately modeling dense plasmas over a wide range of conditions represents an unsolved problem lying at the heart of many important phenomena such as inertial confinement fusion [1], exoplanets and white dwarfs [2,3]. The production of large scale and accurate tabulations of data such as equation of state and transport coefficients as a function of density and temperature is a formidable task, requiring a consistent quantum mechanical treatment of the many-electron problem together with a classical treatment of the nuclear motion. The atoms in the plasma may have bound states or be fully ionized, the electrons may be fully degenerate or approaching their classical limit. The nuclear fluid can range from weakly through to strongly coupled. A consistent, reliable and accurate treatment across all these physical regimes with an approach that remains computationally tractable remains as an open problem.Plasmas of interest are typically one to thousands of times solid density, and have temperatures from about 1eV (∼10kK) to thousands of eV. The difficulty of creating and controlling such plasmas in the laboratory explains the lack of experimental data to guide theoretical development, though ongoing campaigns at National Ignition Facility [4] and elsewhere (eg.[5]), and recent advances in X-ray scattering techniques [6] are beginning to shed light on this problem.From a simulations perspective, powerful and complex tools exist that can provide benchmark calculations. In the lower temperature regime (a few eV) one such tool is Kohn-Sham (KS) density functional theory molecular dynamics (DFT-MD) (eg. [7]). Electrons are treated quantum mechanically through KS-DFT and ions are propagated with classical MD. The simulations are very computationally expensive and this cost scales poorly with temperature, limiting the method to lower temperatures. In practice KS-DFT-MD also relies on a pseudopotential approximation, which reduces the computational overhead by limiting the number of actively modeled electrons, through an ad hoc modification of the electron- (r), n ext e (r) and n P A e (r), as described in the text. Also shown is the bound state (or ion) contribution (n ion e (r)) to n P A e (r) and the valence electron contribution n scr e (r). The double peak structure in n ion e (r) reflects the bound state shell structure in the aluminum ion, while the oscillations in the valence contribution n scr e (r) are the well known Friedel oscillations, whic...

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“…The quantum Ornstein-Zernike (QOZ) equations [32] for a mixture of quantal electrons and N classical ion species were derived in reference [21]…”

Section: B Quantum Ornstein-zernike Equationsmentioning

confidence: 99%

Model for the electrical conductivity in dense plasma mixtures

Starrett

Shaffer

Saumon

et al. 2020

High Energy Density Physics

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A new model for the electrical conductivity of dense plasmas with a mixture of ion species, containing no adjustable parameters, is presented. The model takes the temperature, mass density and relative abundances of the species as input. It takes into account partial ionization, ionic structure, and core-valence orthogonality, and uses quantum mechanical calculations of cross sections. Comparison to an existing high fidelity but computationally expensive method reveals good agreement. The new model is computationally efficient and can reach high temperatures. A new mixing rule is also presented that gives reasonably accurate conductivities for high temperature plasma mixtures.

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Integral equation model for warm and hot dense mixtures

Cited by 33 publications

References 39 publications

Isochoric, isobaric, and ultrafast conductivities of aluminum, lithium, and carbon in the warm dense matter regime

Isochoric, isobaric, and ultrafast conductivities of aluminum, lithium, and carbon in the warm dense matter regime

Pseudoatom molecular dynamics

Model for the electrical conductivity in dense plasma mixtures

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