A5013119318- High-pressure geophysics and materials
- Laser-induced spectroscopy and plasma
- Advanced Chemical Physics Studies
- Laser Material Processing Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Atomic and Molecular Physics
- Ion-surface interactions and analysis
- Advanced Materials Characterization Techniques
- Laser-Plasma Interactions and Diagnostics
- nanoparticles nucleation surface interactions
- Diamond and Carbon-based Materials Research
- Force Microscopy Techniques and Applications
- Surface and Thin Film Phenomena
- Electron and X-Ray Spectroscopy Techniques
- Geological and Geochemical Analysis
- Quantum, superfluid, helium dynamics
- Dust and Plasma Wave Phenomena
- Nuclear Physics and Applications
- X-ray Diffraction in Crystallography
- Thin-Film Transistor Technologies
- Laser-Matter Interactions and Applications
- Semiconductor materials and devices
- Laser-Ablation Synthesis of Nanoparticles
- Spectroscopy and Quantum Chemical Studies
- Advanced X-ray Imaging Techniques
CEA DAM Île-de-France
2015-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2015-2024
Université Paris-Saclay
2020-2024
CEA Paris-Saclay
2020-2024
Sandia National Laboratories
2024
European X-Ray Free-Electron Laser
2018
SLAC National Accelerator Laboratory
2018
Centre National de la Recherche Scientifique
2009-2014
Laboratoire pour l'utilisation des lasers intenses
2014
Université de Bordeaux
2009-2014
We report the results of second charged-particle transport coefficient code comparison workshop, which was held in Livermore, California on 24–27 July 2023. This workshop gathered theoretical, computational, and experimental scientists to assess state computational techniques for understanding coefficients relevant high-energy-density plasma science. Data electronic ionic coefficients, namely, direct current electrical conductivity, electron thermal ion shear viscosity, conductivity were...
The effect of intense ultrashort irradiation on interatomic forces, crystal stability, and possible melting transition the underlying lattice is not completely elucidated. By using ab initio linear response to compute phonon spectrum gold, silicon, aluminum, we found that silicon gold behave in opposite ways when increasing radiation intensity: whereas a weakening bond induces instability, undergoes sharp increase its temperature, while significantly smaller observed for aluminum electronic...
The electronic behavior of various solid metals (Al, Ni, Cu, Au, Ti, and W) under ultrashort laser irradiation is investigated by means density functional theory. Successive stages extreme nonequilibrium on picosecond time scale impact the excited material properties in terms optical coupling transport characteristics. As these are generally modelled based free-electron classical theory, number a key parameter. However, this parameter remains unclearly defined dependencies temperature not...
Studies of laser-heated materials on femtosecond timescales have shown that the interatomic potential can be perturbed at sufficiently high laser intensities. For gold, it has been postulated to undergo a strong stiffening leading an increase phonon energies, known as hardening. Despite efforts investigate this behavior, only measurements low absorbed energy density performed, for which interpretation experimental data remains ambiguous. By using in situ single-shot x-ray diffraction hard...
We present here a technique to compute electronic thermal conductivity of fluids using quantum-molecular dynamics and the formulation Chester-Tellung for Kubo-Greenwood formula. In order validate our implementation, electrical conductivities liquid aluminum were determined from $70\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ above melting point up $10\phantom{\rule{0.2em}{0ex}}000\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Results agree well with experimental data Al at...
Ab initio molecular dynamics is used to compute the thermal conductivity of hydrogen at $80\text{ }\text{ }\mathrm{g}\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$ and temperature up 800 eV. Pressures ionic structure are compared with orbital-free calculations. Thermal evaluated using Kubo-Greenwood formula models currently in hydrodynamical simulations inertial confinement fusion.
Using a chirped pulse probe technique, we have obtained single-shot measurements of temporal evolution ac conductivity at 1.55 eV (800 nm) during electron energy relaxation in nonequilibrium warm dense gold with densities up to $4.1\text{ }\text{ }\mathrm{MJ}/\mathrm{kg}$ ($8\ifmmode\times\else\texttimes\fi{}{10}^{10}\text{ }\mathrm{J}/{\mathrm{m}}^{3}$). The results uncover important changes that been masked an earlier experiment. Equally significant, they provide valuable tests ab initio...
We present an overview of some recent theoretical and experimental results obtained on the properties iron silica at conditions encountered in planetary interiors. The first part is concerned with development x-ray absorption near edge spectroscopy dynamical experiments using high-energy lasers as a tool to investigate phase transitions structural changes extreme pressure–temperature for these two key constituents. second focuses quasi-isentropic compression technique achieve anticipated...
We present a model to describe thermophysical and optical properties of two-temperature systems consisted heated electrons cold ions in solid lattice that occur during ultrafast heating experiments. Our is based on ab initio simulations within the framework density functional theory. The are obtained by evaluating Kubo-Greenwood formula. By applying material parameters our we able temperature relaxation process femtosecond-laser-heated gold its same theoretical framework. Recent...
The melting curve of gold has been measured up to 110 GPa using laser-heated diamond anvil cells and synchrotron x-ray diffraction techniques. Accurate pyrometry temperature measurements a homogeneous heating the sample were achieved by implementing assembly consisting two boron-doped cupped disks sandwiching sample. In investigated pressure range, fcc solid remains stable melting. A clear structural signature bulk is observed. Ab initio molecular dynamics simulations within two-phase...
Using ultrafast x-ray probing, we experimentally observed a progressive loss of ordering within solid-density aluminum as the temperature raises from 300 K to >10{4} K. The Al sample was isochorically heated by short ( approximately ps), laser-accelerated proton beam and probed broadband source around edge. short-range is detected through smoothing time-resolved absorption near-edge spectroscopy (XANES) structure. results are compared with two different theoretical models warm dense matter...
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...
Ab initio molecular dynamics is used to compute the thermal and electrical conductivities of hydrogen from 10 160 g cm–3 temperatures up 800 eV, i.e., thermodynamical conditions relevant inertial confinement fusion (ICF). The ionic structure obtained using simulations based on an orbital-free treatment for electrons. transport properties were computed ab in DFT/LDA approximation. are evaluated Kubo–Greenwood formulation. Particular attention paid convergence electronic with respect number...
The electronic structure evolution of highly compressed aluminum has been investigated using time resolved $K$ edge x-ray absorption spectroscopy. A long laser pulse (500 ps, ${I}_{L}\ensuremath{\approx}8\ifmmode\times\else\texttimes\fi{}{10}^{13}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$) was used to create a uniform shock. second ps (${I}_{L}\ensuremath{\approx}{10}^{17}\text{ generated an ultrashort broadband source near the Al edge. main target designed probe at reshocked conditions...
Taking advantage of the new opportunities provided by x-ray free electron laser (FEL) sources when coupled to a long pulse as available at Linear Coherent Light Source (LCLS), we have performed absorption near-edge spectroscopy (XANES) shock compressed iron up 420 GPa ($\ifmmode\pm\else\textpm\fi{}50$) and 10 800 K ($\ifmmode\pm\else\textpm\fi{}1390$). Visible diagnostics with hydrodynamic simulations were used infer thermodynamical conditions along Hugoniot release adiabat. A modification...
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...
A time and polarization resolved reflective interferometry measurement on femtosecond laser heated gold is presented. We deduced the electron momentum damping frequency, conduction density, finally temperature in $0.6--5\phantom{\rule{0.28em}{0ex}}\mathrm{eV}$ range out of equilibrium, solid density warm dense gold. This allows experimental determination electron-electron collision frequency variation with matter conditions. The comparison several models shows importance properly taking into...
We have performed orbital-free and quantum molecular dynamics simulations on plastic ablator along two isochores, namely 7 9 g cm${}^{\ensuremath{-}3}$, from 5 to 40 eV. These thermodynamic conditions correspond those encountered during inertial confinement fusion capsule implosion when hydrodynamic instabilities can take place. The coupling between approaches allowed us compute an exhaustive set of microscopic coefficients, i.e., equation-of-state, ionic diffusion thermal electrical...
We have probed, with time-resolved x-ray absorption near-edge spectroscopy (XANES), a femtosecond-laser-heated aluminum foil fluences up to 1 J/cm2. The spectra reveal loss of the short-range order in few picoseconds. This time scale is compared electron-ion equilibration time, calculated two-temperature model. Hydrodynamic simulations shed light on complex features that affect dynamics, including progressive density change from solid liquid (∼10 ps). In this range, quantum molecular...
We present simulations using finite-temperature density-functional-theory molecular-dynamics to calculate dynamic dielectric properties in warm dense aluminum. The comparison between exchange-correlation functionals the Perdew, Burke, Ernzerhof approximation, Strongly Constrained and Appropriately Normed Semilocal Density Functional, Heyd, Scuseria, (HSE) approximation indicates evident differences electron transition energies, dc conductivity, Lorenz number. HSE calculations show excellent...
We present an ab initio study of MgO at high temperature and pressure, around the phase transition between B1 B2 phases. By means molecular dynamic calculations, thermal evolution vibrational properties thermodynamic quantities is obtained. carefully compare our results with previous theoretical works on curve we analyze differences among them. show that anharmonic effects have been underestimated in quasiharmonic approximation their inclusion free energy strongly straightens up curve. Then,...
Using a combination of classical and ab-initio molecular dynamics simulations, we calculate the structure electrical conductivity warm dense gold during first picoseconds after short-pulse laser illumination. We find that ions remain in their initial fcc for several picoseconds, despite electron temperatures ranging from few to eV The conductivities calculated under these nonequilibrium conditions using latter assumption are remarkable agreement with recent measurements interacting thin films.