A5002001418- Atomic and Molecular Physics
- Advanced Chemical Physics Studies
- Laser-induced spectroscopy and plasma
- High-pressure geophysics and materials
- X-ray Spectroscopy and Fluorescence Analysis
- Mass Spectrometry Techniques and Applications
- Stellar, planetary, and galactic studies
- Solar and Space Plasma Dynamics
- Laser-Plasma Interactions and Diagnostics
- Electron and X-Ray Spectroscopy Techniques
- Ion-surface interactions and analysis
- Astro and Planetary Science
- Dust and Plasma Wave Phenomena
- Astrophysics and Star Formation Studies
- Plasma Diagnostics and Applications
- Spectroscopy and Quantum Chemical Studies
- Advanced Thermodynamics and Statistical Mechanics
- Cold Atom Physics and Bose-Einstein Condensates
- Laser-Matter Interactions and Applications
- nanoparticles nucleation surface interactions
- Statistical Mechanics and Entropy
- Quantum, superfluid, helium dynamics
- Astronomical Observations and Instrumentation
- Laser Design and Applications
- Surface and Thin Film Phenomena
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2016-2025
CEA DAM Île-de-France
2016-2025
Université Paris-Saclay
2021-2025
CEA Paris-Saclay
2021-2025
Observatoire de Paris
2011-2012
Centre National de la Recherche Scientifique
1996-2012
Janssen (France)
2009-2012
Laboratoire Univers et Théories
2007-2009
Los Alamos National Laboratory
2008
Lawrence Livermore National Laboratory
2008
Theoretical opacities are required for calculating energy transport in plasmas. In particular, understanding stellar interiors, inertial fusion, and Z pinches depends on the of mid-atomic-number elements over a wide range temperatures. The 150–300 eV temperature is particularly interesting. opacity models complex experimental validation crucial. For example, solar presently disagree with helioseismology one possible explanation inadequate theoretical opacities. Testing these requires...
An opacity model (OPAS) combining detailed configuration and level accounting treatments has been developed to calculate radiative of plasmas in local thermodynamic equilibrium. The is presented used compute spectral opacities a solar mixture. Various density–temperature couples have considered from the center up vicinity radiative/convective zone interface. For given path, OPAS calculations are compared Opacity Project (OP) OPAL data. Rosseland mean values very good agreement over all while...
The first systematic study of opacity dependence on atomic number at stellar interior temperatures is used to evaluate discrepancies between measured and modeled iron [J. E. Bailey et al., Nature (London) 517, 56 (2015)NATUAS0028-083610.1038/nature14048]. High-temperature (>180 eV) chromium nickel opacities are with ±6%-10% uncertainty, using the same methods employed in previous experiments. 10%-20% experiment reproducibility demonstrates reliability. overall model-data disagreements...
The Sun is the most studied of all stars, and thus constitutes a benchmark for stellar models. However, our vision still incomplete, as illustrated by current debate on its chemical composition. problem reaches far beyond abundances intimately linked to microscopic macroscopic physical ingredients solar models such radiative opacity, which experimental results have been recently measured that await theoretical explanations. We present opacity profiles derived from helioseismic inferences...
Calculations of equation state, transport coefficients, and stopping power dense plasmas are presented. Theoretical results have been obtained using the first-principles average-atom model self-consistent approach for astrophysical laboratory (SCAALP) based on finite-temperature density-functional theory Gibbs–Bogolyubov inequality. Numerical results, comparisons with molecular dynamics, Monte Carlo simulations experiments presented discussed in high energy density physics domain including...
Opacity model differences with Fe opacity measurements at high temperature (T>180 eV) and electron density (n_{e}>3×10^{22} cm^{-3}) nearly solar interior conditions have remained unresolved [Bailey et al., Nature 517, 56 (2015)10.1038/nature14048 Nagayama Phys. Rev. Lett. 122, 235001 (2019)PRLTAO0031-900710.1103/PhysRevLett.122.235001]. Systematic errors from temporal gradients are one hypothesis for the discrepancy. Past data recorded on x-ray film provided spectral over a time determined...
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...
The OPAS opacity model has been used to calculate the radiative of stellar plasmas in local thermodynamic equilibrium. According recent chemical composition revision solar photosphere, opacities have computed for various hydrogen and metallic element mass fractions. Calculations performed toward interior modeling temperatures between , electron densities . We discuss possible sources uncertainty calculations. also compare Rosseland OPAL OP data.
This paper presents an improved analytical expression for the x-ray dynamic structure factor from a dense plasma which includes effects of weakly bound electrons. result can be applied to describe scattering low moderate Z plasmas, and it covers entire range conditions that found in inertial confinement fusion experiments, ideal degenerate up moderately coupled systems. The theory is used interpret experiments solid density carbon plasmas extract accurate measurements electron temperature,...
A set of materials—titanium, copper, and germanium—has been experimented with at the OMEGA laser facility [Boehly, Opt. Commun. 133, 495 (1997)] by irradiating thin foils a prepulse prior to main pulse variable delay, in order design efficient x-ray laser-sources for backlighting, material testing, code validation. This concept led increasing factors from 2 4 comparing cases without prepulse, experimental conditions. As result, high multi-keV conversion rates have obtained: 9% titanium...
We hereby present a model to describe the thermodynamic and transport properties of dense plasmas. The electronic ionic structures are determined self-consistently using finite-temperature density functional theory Gibbs-Bogolyubov inequality. main quantities, i.e., internal energy, pressure, entropy, sound speed, obtained by numerical differentiation plasma total Helmholtz free energy. Electronic electrical thermal conductivities calculated from Ziman approach. Ionic coefficients estimated...
Photoelectron data are reported for the first measurement of even-parity hollow lithium states produced by triple photoexcitation laser-excited atoms. Calculations using R-matrix approximation energy these and partial photoionization cross sections also reported. Experiment theory in excellent agreement on a relative scale.
Isochore measurements were performed in the warm dense matter regime. Pressure and internal energy variation of aluminum plasma (density 0.1 g/cm(3) 0.3 g/cm(3)) are measured using a homogeneous thermally equilibrated media produced inside an isochoric closed vessel range 20-50 MJ/kg. These data compared to detailed calculations obtained from ab initio quantum molecular dynamics, average atom model within framework density functional theory, standard theories. A dispersion between...
Photoelectron data for hollow lithium states obtained with unprecedented high spectral resolution and sensitivity are presented. A critical comparison is made the most recent theoretical results. Partial cross sections measured providing first definitive test of advanced ab initio calculations this highly excited four-body atomic system.
Understanding stellar interiors, inertial confinement fusion, and Z pinches depends on opacity models for mid-Z plasmas in the 100-300 eV temperature range. These are complex experimental validation is crucial. In this paper we describe diagnosis of first experiments to measure iron plasma at a high enough produce charge states electron configurations that exist solar interior. The dynamic Hohlraum x-ray source Sandia National Laboratories' facility was used both heat backlight Mg/Fe CH...
Absolute cross sections for the K-shell photoionization of C-like nitrogen ions were measured by employing ion-photon merged-beam technique at SOLEIL synchrotron radiation facility in Saint-Aubin, France. High-resolution spectroscopy with E/$\Delta$E $\approx$ 7,000 was achieved photon energy from 388 to 430 eV scanned a band pass 300 meV, and 399.4 402 range 60 meV. Experimental results are compared theoretical predictions made multi-configuration Dirac-Fock (MCDF) R-matrix methods. The...
Photoionization cross sections of halogen-like Kr+ and Xe+ ions have been measured in the photon energy range extending up to 15 eV above threshold. Two different devices were used, a merged-beam set-up an ion trap. Combination two techniques allows for extraction pure ground state ionization section on absolute scale. Multiconfiguration Dirac–Fock calculations reproduce magnitude direct photoionization well.
Measurements of absolute cross sections for the K-shell photoionization B-like atomic nitrogen ions were carried out utilizing ion–photon merged-beam technique at SOLEIL synchrotron radiation facility in Saint-Aubin, France. High-resolution spectroscopy with E/ΔE ≈13,500 was maximum resolution achieved. We have investigated two photon energy regions: 404–409 eV and 439–442 eV. Resonance peaks found experimental measured are compared theoretical estimates from multi-configuration Dirac–Fock,...
Electrical resistivity is shown to saturate in solid-density aluminum the warm dense matter regime. Calculations are done using average-atom model SCAALP and finite-temperature Ziman-Evans formula for electrical resistivity. The mean free path estimated Drude law. This present a minimum of order interatomic spacing.
Stellar seismology appears more and as a powerful tool for better determination of the fundamental properties solar-type stars. However, particular case Sun is still challenging. For about decade now, helioseismic sound-speed has continued to disagree with standard solar model (SSM) prediction, questioning reliability this model. One sources uncertainty could be in treatment transport radiation from core surface. In Letter, we use new OPAS opacity tables, recently available modeling, address...
Abstract We present absolute L-shell photoionisation cross sections for the S+, S2+, S3+ ions. The were obtained using monochromatised photon beam delivered by SOLEIL syn- chrotron source coupled with an ion extracted from electron cyclotron resonance (ECRIS) in merged dual-beam configuration. single, double and triple ionisation measured combined to generate total sections. For each of S2+ ions, energy regions corresponding excitation a 2p or 2s (∼ 175-230 eV) investigated. experimental...
ABSTRACT In this article, we examine different approaches for calculating low frequency opacities in the warm dense matter regime. The relevance of average‐atom approximation and models opacities, such as Ziman or Ziman–Evans is discussed results compared to ab initio simulations. We begin by recalling derivation resistivity from Kubo's linear response theory, using local solutions Lippmann–Schwinger equation. With help approximation, explicitly introduce an ionic structure factor into...