A5066926675- Laser-induced spectroscopy and plasma
- High-pressure geophysics and materials
- Atomic and Molecular Physics
- Advanced Chemical Physics Studies
- Dust and Plasma Wave Phenomena
- Laser-Plasma Interactions and Diagnostics
- nanoparticles nucleation surface interactions
- Laser-Matter Interactions and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Plasma Diagnostics and Applications
- Quantum, superfluid, helium dynamics
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Phase Equilibria and Thermodynamics
- Material Dynamics and Properties
- Ionosphere and magnetosphere dynamics
- Diamond and Carbon-based Materials Research
- Stellar, planetary, and galactic studies
- Gas Dynamics and Kinetic Theory
- Chemical and Physical Properties of Materials
- Mass Spectrometry Techniques and Applications
- Characterization and Applications of Magnetic Nanoparticles
- Energetic Materials and Combustion
- Advanced Thermodynamics and Statistical Mechanics
- Geological and Geophysical Studies
University of Rochester
2022-2025
Energetics (United States)
2022-2025
Los Alamos National Laboratory
2016-2023
Applied Energetics (United States)
2023
The University of Texas at Austin
2022
Pacific Northwest National Laboratory
2022
University of Iowa
2016-2019
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...
Inverse bremsstrahlung absorption was measured based on transmission through a finite-length plasma that thoroughly characterized using spatially resolved Thomson scattering. Expected then calculated the diagnosed conditions while varying model components. To match data, it is necessary to account for (i) Langdon effect; (ii) laser-frequency (rather than plasma-frequency) dependence in Coulomb logarithm, as typical of theories but not transport theories; and (iii) correction due ion...
Spectroscopic measurements of dense plasmas at billions atmospheres provide tests to our fundamental understanding how matter behaves extreme conditions. Developing reliable atomic physics models these conditions, benchmarked by experimental data, is crucial an improved radiation transport in both stars and inertial fusion targets. However, detailed spectroscopic conditions are rare, traditional collisional-radiative equilibrium models, based on isolated-atom calculations ad hoc continuum...
It was recently shown that the use of Coulomb logarithms appropriate for bremsstrahlung radiation (rather than transport processes) along with corrections Langdon effect and ion screening reproduced measurements collisional absorption in well-characterized underdense plasmas [D. Turnbull et al., Phys. Rev. Lett. 130, 145103 (2023)]. However, it recognized at time standard absorption-reduction factor from Langdon's seminal paper inconsistent are thermally averaged over a Maxwellian...
Heat transport across interfaces is a ubiquitous phenomenon with many unresolved aspects. In particular, it unknown if an interfacial thermal resistance (ITR) occurs in matter high-energy-density where free electrons dominate the heat conduction. Here, we report on first experimental evidence that significant barrier present between two different regions of matter: strongly heated tungsten wire and surrounding plastic layer stays relatively cold. We use diffraction-enhanced imaging to track...
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...
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...
Self-diffusion and interdiffusion coefficients of binary ionic mixtures are evaluated using the Effective Potential Theory (EPT), predictions compared with results molecular dynamics simulations. We find that EPT agrees from weak coupling well into strong regime, which is a similar range strengths as previously observed in comparisons one-component plasma. Within this range, typical relative errors approximately 20% worst-case 40% observed. also examine Darken model, approximates based on...
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,...
In the dynamic-shell (DS) concept [V. N. Goncharov et al., Novel Hot-Spot Ignition Designs for Inertial Confinement Fusion with Liquid-Deuterium-Tritium Spheres, Phys. Rev. Lett. 125, 065001 (2020).] laser-driven inertial confinement fusion deuterium-tritium fuel is initially in form of a homogeneous liquid inside wetted-foam spherical shell. This ignited using conventional implosion, which preceded by initial compression followed its expansion and dynamic formation high-density shell...
Nonlocal electron transport is important for understanding laser-target coupling laser-direct-drive (LDD) inertial confinement fusion (ICF) simulations. Current models the nonlocal mean free path in radiation-hydrodynamic codes are based on plasma-physics developed decades ago; improvements needed to accurately predict conduction LDD simulations of ICF target implosions. We utilized time-dependent density functional theory (TD-DFT) calculate stopping power (SP) so-called conduction-zone...
Using molecular dynamics simulations, we perform the first direct tests of three proposed models for pair correlation functions strongly coupled plasmas with species unequal temperature. The are all extensions Ornstein–Zernike/hypernetted-chain theory used to good success equilibrium plasmas. Each is evaluated at several coupling strengths, temperature ratios, and mass ratios a model plasma in which electrons positively charged. We show that by Seuferling et al. [Phys. Rev. A 40, 323 (1989)]...
The calculation of the optical properties hot dense plasmas with a model that has self-consistent plasma physics is grand challenge for high energy density science. Here we exploit recently developed electronic structure uses multiple scattering theory to solve Kohn-Sham functional equations plasmas. We calculate opacities in this regime, validate method, and apply it recent experimental measurements opacity Cr, Ni, Fe. Good agreement found quasicontinuum region Cr while approach cannot...
Accurate knowledge of the electronic transport properties warm dense matter is one main concerns research in high-energy-density physics. Three modern approaches with vastly different levels fidelity are reviewed and compared: Kubo–Greenwood (KG) approach based on density-functional-theory molecular dynamics simulations (QMD), quantum kinetic theory average-atom models, time-dependent density functional theory. Throughout, emphasis placed connection between static electrons (e.g., states)...
We describe an experimental concept at the National Ignition Facility for specifically tailored spherical implosions to compress hydrogen extreme densities (up ∼800× solid density, electron number density ne∼4×1025 cm−3) moderate temperatures (T∼200 eV), i.e., conditions, which are relevant interiors of red dwarf stars. The dense plasma will be probed by laser-generated x-ray radiation different photon energy determine opacity due collisional (free–free) absorption and Thomson scattering....
Warm dense matter is a material state in the region of parameter space connecting condensed to classical plasma physics. In this intermediate regime, we investigate significance non-adiabatic electron-ion interactions upon ion dynamics. To disentangle from adiabatic interactions, compare self-diffusion coefficient electron force field computational model with an adiabatic, molecular dynamics simulation. A pair potential developed through force-matching algorithm ensures only difference...
We present a model of the electron thermal conductivity laser-produced plasma. The model, supported by Vlasov-Fokker-Planck simulations, predicts that laser absorption reduces forcing electrons out Maxwell-Boltzmann equilibrium, which results in depletion both low-velocity bulk and high-velocity tail electrons. show approximately follow super-Gaussian distributions, but with distinct exponents each depend on intensity wavelength through parameter α=Zv_{E}^{2}/v_{T}^{2}. For value α=0.5, to...
The pressure and internal energy of an ultracold plasma in a state quasi-equilibrium are evaluated using classical molecular dynamics simulations. Coulomb collapse is avoided by modeling electron-ion interactions attractive potential with repulsive core. We present method to separate the contribution bound states, which form due recombination, from free charges when evaluating these thermodynamic variables. It found that independent choice core length-scale it sufficiently short-ranged....
A wide-range (0 to 1044.0 g/${\mathrm{cm}}^{3}$ and 0 ${10}^{9}$ K) equation-of-state (EOS) table for a ${\mathrm{CH}}_{1.72}{\mathrm{O}}_{0.37}{\mathrm{N}}_{0.086}$ quaternary compound has been constructed based on density-functional theory (DFT) molecular-dynamics (MD) calculations using combination of Kohn-Sham DFT MD, orbital-free numerical extrapolation. The first-principles EOS data are compared with predictions simple models, including the fully ionized ideal gas Fermi-degenerate...
Recently developed free-energy density functional theory (DFT)-based methodology for optical property calculations of warm dense matter has been applied studying L-shell opacity iron and chromium at T=182 eV. We use Mermin-Kohn-Sham with a ground-state fully-temperature-dependent generalized gradient approximation exchange-correlation (XC) functionals. It is demonstrated that the role XC such high-T negligible due to total free energy interacting systems being dominated by noninteracting...
Charge state distributions in hot, dense plasmas are a key ingredient the calculation of spectral quantities like opacity. However, they challenging to calculate, as models Saha–Boltzmann become unreliable for dense, quantum plasmas. Here, we present new variational model charge distribution, along with simple energy configurations that includes orbital relaxation effect. Comparison other methods reveals generally good agreement average atom-based calculations, breakdown method, and mixed...
Vlasov–Fokker–Planck simulation codes occupy an important niche in modeling laser-produced plasmas, since they are well suited to studying the effect of collisions on electron kinetic phenomena, especially energy transport. One most elements transport is absorption laser light by plasma; however, simulating this detail requires resolving oscillations light, whose characteristic timescale orders magnitude shorter than time needed study physics. For reason, used plasmas rely simplified models...