Super-transition-arrays: A model for the spectral analysis of hot, dense plasma

Bar‐Shalom, A.; Oreg, J.; Wh, Goldstein; Shvarts, D.; Zigler, A.

doi:10.1103/physreva.40.3183

Cited by 370 publications

(256 citation statements)

References 15 publications

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“…For opacity models where the profiles near line center have been compromised (e.g. ; statistical line accounting methods [25,26]), the results suggest neglecting the highly excited spectator electron contributions in the width calculations.…”

Section: Discussionmentioning

confidence: 98%

Excited spectator electron effects on spectral line shapes

Iglesias

2010

High Energy Density Physics

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Excited spectator electron effects on Stark broadened spectral line shapes of transitions involving tightly bound electrons are investigated. It is shown that the interference terms in the electron impact broadening are essential to describe the overlapping lines generated by these configurations (e.g.; dielectronic satellite lines). The main impact is narrower spectral features and reduced far wing intensities compared to calculations neglecting the interference terms.

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Section: Discussionmentioning

confidence: 98%

Excited spectator electron effects on spectral line shapes

Iglesias

2010

High Energy Density Physics

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“…In other cases, transition arrays are represented by Gaussian profiles in the UTA (Unresolved Transition Array [22,23]) or SOSA (Spin-Orbit Split Array [24]) formalisms. If the Rydberg supershell contains at least one electron, then transitions starting from the super-configuration are taken into account by the Super Transition Array (STA) model [25]. The amount of detailed calculations performed in SCO-RCG is now largely dominant.…”

Section: Radiative Opacitymentioning

confidence: 99%

“…It enables one to replace many statistical transition arrays by small-scale DLA calculations. We have extended this approach to the STA formalism [25], consisting in omitting the Rydberg supershell in the computation, and adding its contribution to the widths of all lines. The contribution of the Rydberg supershell is included as a Gaussian "dressing function" [17].…”

Section: Radiative Opacitymentioning

confidence: 99%

Detailed Opacity Calculations for Astrophysical Applications

Pain

Gilleron

Comet

2017

Atoms

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Nowadays, several opacity codes are able to provide data for stellar structure models, but the computed opacities may show significant differences. In this work, we present state-of-the-art precise spectral opacity calculations, illustrated by stellar applications. The essential role of laboratory experiments to check the quality of the computed data is underlined. We review some X-ray and XUV laser and Z-pinch photo-absorption measurements as well as X-ray emission spectroscopy experiments involving hot dense plasmas produced by ultra-high-intensity laser irradiation. The measured spectra are systematically compared with the fine-structure opacity code SCO-RCG. The focus is on iron, due to its crucial role in understanding asteroseismic observations of β Cephei-type and Slowly Pulsating B stars, as well as of the Sun. For instance, in β Cephei-type stars, the iron-group opacity peak excites acoustic modes through the "kappa-mechanism". Particular attention is paid to the higher-than-predicted iron opacity measured at the Sandia Z-machine at solar interior conditions. We discuss some theoretical aspects such as density effects, photo-ionization, autoionization or the "filling-the-gap" effect of highly excited states.

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“…The problem is that, in hot plasmas, the number of configurations can be really huge. The super-configuration method [4] has been invented in order to remedy this problem. A configuration is made of orbitals with integer populations; in the same way, a super-configuration is made of super-orbitals with integer populations, a super-orbital being a group of orbitals which energies are close to each other.…”

Section: Canonical Ensemblementioning

confidence: 99%

“…A few years ago, Blenski et al [2,3] generalized the statistical HartreeFock approach to atoms in plasmas at finite temperature in the framework of the super-configuration approximation successfully applied in the STA (Super Transition Array) method [4]. In the following, such a theory will be refered to as "canonical statistical HF theory".…”

Section: Introductionmentioning

confidence: 99%

Koopmans' theorem in the statistical Hartree–Fock theory

Pain¹

2011

J. Phys. B: At. Mol. Opt. Phys.

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In this short paper, the validity of Koopmans' theorem in the Hartree-Fock theory at non-zero temperature (Hartree-Fock statistical theory) is investigated. It is shown that Koopmans' theorem does not apply in the grand-canonical ensemble, due to a missing contribution to the energy proportional to the interaction between two electrons belonging to the same orbital. Hartree-Fock statistical theory has also been applied in the canonical ensemble [Blenski et al., Phys. Rev. E 55, R4889 (1997)] for the purpose of photo-absorption calculations. In that case, the Hartree-Fock self-consistent-field equations are derived in the super-configuration approximation. It is shown that Koopmans' theorem does not hold in the canonical ensemble, but that a restricted version of the theorem can be obtained, by assuming that a particular quantity multiplying the interaction matrix element in the expression of the energy does not change during the removal of an electron.

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Super-transition-arrays: A model for the spectral analysis of hot, dense plasma

Cited by 370 publications

References 15 publications

Excited spectator electron effects on spectral line shapes

Excited spectator electron effects on spectral line shapes

Detailed Opacity Calculations for Astrophysical Applications

Koopmans' theorem in the statistical Hartree–Fock theory

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