A5014330707- Laser-induced spectroscopy and plasma
- Laser-Plasma Interactions and Diagnostics
- Atomic and Molecular Physics
- High-pressure geophysics and materials
- Astro and Planetary Science
- X-ray Spectroscopy and Fluorescence Analysis
- Plasma Diagnostics and Applications
- Advanced Chemical Physics Studies
- Solar and Space Plasma Dynamics
- Laser-Matter Interactions and Applications
- Ion-surface interactions and analysis
- Stellar, planetary, and galactic studies
- Nuclear Physics and Applications
- Ionosphere and magnetosphere dynamics
- Electron and X-Ray Spectroscopy Techniques
- Combustion and Detonation Processes
- Magnetic confinement fusion research
- Geomagnetism and Paleomagnetism Studies
- Energetic Materials and Combustion
- Advanced X-ray and CT Imaging
- Mass Spectrometry Techniques and Applications
- Nuclear physics research studies
- Gas Dynamics and Kinetic Theory
- Planetary Science and Exploration
- Advanced X-ray Imaging Techniques
Los Alamos National Laboratory
2016-2025
University of Michigan
2021
Computational Physics (United States)
2013-2019
University of Nevada, Reno
2002-2015
P.N. Lebedev Physical Institute of the Russian Academy of Sciences
2009
Brigham Young University
2009
Max Planck Society
2002-2008
Max Planck Institute of Quantum Optics
2002-2008
Saint Peter's University
2004
The Los Alamos suite of relativistic atomic physics codes is a robust, mature platform that has been used to model highly charged ions in variety ways. includes capabilities for calculating data related fundamental structure, as well the processes photoexcitation, electron-impact excitation and ionization, photoionization autoionization within consistent framework. These can be basic nature, such cross sections collision strengths, which are useful making predictions compared with...
We present a new, publicly available, set of Los Alamos OPLIB opacity tables for the elements hydrogen through zinc. Our are computed using ATOMIC and plasma modeling code, make use atomic structure calculations that fine-structure detail all considered. equation-of-state (EOS) model, known as ChemEOS, is based on minimization free energy in chemical picture appears to be reasonable robust approach determining state populations over wide range temperatures densities. In this paper we discuss...
Context. As a result of the high-quality constraints available for Sun, we are able to carry out detailed combined analyses using neutrino, spectroscopic, and helioseismic observations. These studies lay ground future improvements key physical components solar stellar models because ingredients such as equation state, radiative opacities, or prescriptions macroscopic transport processes chemicals then used study other stars in Universe. Aims. We existing degeneracies recent high-metallicity...
Abstract We present a set of 1194 Type-1 Rosseland-mean opacity tables for four different metallicity mixtures. These new Los Alamos OPLIB atomic radiative are an order magnitude larger in number than any previous table release, and span regimes where have not existed. For example, the expands range to Z = 10 −6 0.2, which allows improved accuracy opacities at low high metallicity, increases density −4 0.1 enhance drawn from interpolations across neighboring metallicities, adds entries...
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...
Temporally, spatially, and spectrally resolved x-ray image data from direct-drive implosions on OMEGA were interpreted with the aid of radiation-hydrodynamic simulations. Neither clean calculations nor those using a turbulent mix model can explain fully observed migration shell-dopant material (titanium) into core. Shell-dopant was via time-dependent, spatially integrated spectra, images capsule resultant dopant emissions. The titanium emission centrally peaked in narrowband images. In...
We present narrow-band self-emission x-ray images from a titanium tracer layer placed at the fuel-shell interface in 60-laser-beam implosion experiments OMEGA facility. The are acquired during deceleration with inferred convergences of $\ensuremath{\sim}9--14.$ Novel here is that systematically observed asymmetry emission linked, using full sphere 3D modeling, to performance-limiting low mode drive.
We report direct experimental evidence of interspecies ion separation in direct-drive, inertial-confinement-fusion experiments on the OMEGA laser facility. These experiments, which used plastic capsules with D$_2$/Ar gas fill (1% Ar by atom), were designed specifically to reveal exploiting predicted, strong thermo-diffusion between species large mass and charge difference. Via detailed analyses imaging x-ray-spectroscopy data, we extract Ar-atom-fraction radial profiles at different times,...
It is known from experiments that the radiated x-ray energy appears to exceed calculated implosion kinetic and Spitzer resistive heating [C. Deeney et al., Phys. Rev. A 44, 6762 (1991)] but possible mechanisms of enhanced production are still being discussed. Enhanced plasma in small-diameter wire arrays with decreased was investigated, a review cylindrical 1--16 mm diameter on 1 MA Zebra generator presented this paper. The generation different diameters were compared find transition regime...
Abstract Since the observation of first brown dwarf in 1995, numerous studies have led to a better understanding structures these objects. Here we present method for studying material resistivity warm dense plasmas laboratory, which relate microphysics dwarfs through viscosity and electron collisions. use X-ray polarimetry determine sulphur-doped plastic target heated Brown Dwarf conditions by an ultra-intense laser. The is determined matching plasma physics model atomic calculations...
We present a modeling study of x-ray line polarization in plasmas driven by high-intensity, ultrashort duration pulsed lasers. Electron kinetics simulations these transient and nonequilibrium predict non-Maxwellian anisotropic electron distribution functions. Under conditions, the magnetic sublevels within fine structure levels can be unequally populated which leads to emission polarized lines. have developed time-dependent, collisional-radiative atomic model understand underlying processes...
We calculate x-ray line polarization degrees for cases with axial symmetry using a collisional-radiative magnetic-sublevel atomic kinetics model and the properties of multipole radiation fields. This approach is well suited problems where alignment determined by competition between many processes. benchmark this method against measurements performed at Livermore electron beam ion trap, we study 3-to-2 cascade effects on 2-to-1 lines in He-like Fe.
Heat transport in reduced-mass targets irradiated with a high intensity laser pulse was studied. Kα lines from partially ionized chlorine embedded the middle of triple-layered plastic target were measured to evaluate bulk electron temperature tracer region inside target. Two groups lines, one Cl+–Cl6+ (hereby called “cold Kα”), and other Cl9+ Cl10+ (“shifted Kα”) are observed different regions within Two-dimensional collisional particle-in-cell simulations show two distinct heating...
High-resolution laser diagnostics at the wavelength of 266 nm were applied for investigation Z pinches 1-MA generator. The internal structure stagnated was observed in unprecedented detail. A dense pinch with strong instabilities seen inside column trailing plasma. Kink instability, disruptions, and micropinches peak x-ray pulse later time. three-dimensional depends on initial wire-array configuration implosion scenario. Small-scale density perturbations found precursor plasma pinch....
Experiments were performed to develop a platform for the simultaneous measurement of mix and its effects on fusion burn. Two polar direct drive implosions all-plastic capsules conducted first time National Ignition Facility (NIF). To measure implosion trajectory symmetry, area image backlighting these was also employed NIF, an advance over previous 1-D slit imaging experiments, providing detailed symmetry data as they imploded. The low-mode asymmetry seen in resultant radiographs agreed with...
We report the first direct experimental evidence of interspecies ion separation in direct-drive inertial confinement fusion experiments performed at OMEGA laser facility via spectrally, temporally, and spatially resolved imaging x-ray-spectroscopy data [S. C. Hsu et al., Europhys. Lett. 115, 65001 (2016)]. These were designed based on expectation that thermo-diffusion would be strongest for species with a large mass charge difference. The targets spherical plastic shells filled D2 trace...
Dynamics of laser produced plasma in a strong magnetic field was studied using 1 MA pulsed power generator coupled to an intense, high-energy laser. A 2–2.5 MG generated on the surface rod load 0.8–1.2 mm diameter. sub-nanosecond pulse with intensity 3 × 1015 W cm−2 focused surface. Side-on diagnostics showed generation two collimated jets 1–3 long front and rear sides load. End-on reveal that takes form thin disc as propagates along lines. The disc-like expands radially across velocity 250...
The Sun is the most constrained and well-studied of all stars. As a consequence, physical ingredients entering solar models are used as reference to study other stars observed in Universe. However, our understanding structure still imperfect, illustrated by current debate on heavy element abundances Sun. We wish provide additional information carrying out structural inversions new quantity, proxy entropy plasma which properties very sensitive temperature gradient below convective zone. use...