A5050842011- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Nuclear Physics and Applications
- Laser-Matter Interactions and Applications
- High-pressure geophysics and materials
- Magnetic confinement fusion research
- Quantum, superfluid, helium dynamics
- Combustion and Detonation Processes
- Fusion materials and technologies
- Atomic and Subatomic Physics Research
- Gas Dynamics and Kinetic Theory
- Nuclear Materials and Properties
- High-Energy Particle Collisions Research
- Ion-surface interactions and analysis
- Advanced Chemical Physics Studies
- Laser Design and Applications
- Particle physics theoretical and experimental studies
- Parallel Computing and Optimization Techniques
- Advanced Optical Sensing Technologies
- Computational Fluid Dynamics and Aerodynamics
- Solar and Space Plasma Dynamics
- Energetic Materials and Combustion
- Astro and Planetary Science
- Aluminum Alloy Microstructure Properties
- X-ray Spectroscopy and Fluorescence Analysis
Lawrence Livermore National Laboratory
2013-2024
University of Maryland, College Park
2019
Massachusetts Institute of Technology
2000-2016
General Atomics (United States)
2016
Applied Energetics (United States)
2016
Fusion Academy
2016
Fusion (United States)
2016
University of Houston
2003-2005
University of California, Berkeley
2000-2003
Villanova University
2003
We present the first measurement of pseudorapidity densities primary charged particles near midrapidity in Au+Au collisions at sqrt[s(NN)] = 56 and 130 GeV. For most central collisions, we find charged-particle density to be dN/deta|(|eta|<1) 408+/-12(stat)+/-30(syst) GeV 555+/-12(stat)+/-35(syst) GeV, values that are higher than any previously observed nuclear collisions. Compared proton-antiproton our data show an increase per participant by more 40% energy.
Spectroscopic experiments on molecules embedded in free clusters of liquid helium reveal a number unusual features deriving from the unique quantum behavior this nanoscale matrix environment. The apparent rotation small bosonic He4 is one experimentally most well documented these features. In Focus article, we set phenomenon context experimental and theoretical advances field over last ten years, describe microscopic insight which it has provided into nature dynamic consequences solvation...
A detailed simulation-based model of the June 2011 National Ignition Campaign cryogenic DT experiments is presented. The based on integrated hohlraum-capsule simulations that utilize best available models for hohlraum wall, ablator, and equations state opacities. calculated radiation drive was adjusted by changing input laser power to match experimentally measured shock speeds, merger times, peak implosion velocity, bangtime. crossbeam energy transfer tuned time-dependent symmetry. Mid-mode...
The goal of an inertially confined, igniting plasma on the National Ignition Facility (NIF) [M. L. Spaeth, Fusion Sci. Technol. 69, 25 (2016)] remains elusive. However, there is a growing understanding factors that appear to be limiting current implosion performance. And with this understanding, question naturally arises: What conditions will ultimately required achieve ignition, either by continuing improve quality implosions, or hydrodynamically scaling those implosions larger driver...
The inertial confinement fusion program relies upon detailed simulations with (ICF) codes to design targets and interpret the experimental results. These treat as much physics from essential principles is practical, including laser deposition, cross beam energy transfer, x-ray production transport, nonlocal thermal equilibrium kinetics, hydrodynamic instabilities, thermonuclear burn, transport of reaction products. Improvements in radiation code capabilities vast increases computing power...
Summary form only given. The goal of the Grid Application Development Software (GrADS) project is to provide programming tools and an execution environment ease program development for grid. We present recent extensions GrADS software framework: 1. A new approach scheduling workflow computations, applied a 3D image reconstruction application; 2. simple stop/migrate/restart rescheduling grid applications, QR 3. process-swapping rescheduling, N-body simulation. Experiments validating these...
Although computer simulation has played a central role in the study of nucleation and growth since earliest molecular dynamics simulations almost 50 years ago, confusion surrounding effect finite size on such limited their applicability. Modeling solidification molten tantalum Blue Gene/L computer, we report here first atomistic that verifies independence from finite-size effects during entire process, up to onset coarsening. We show scaling theory explains observed maximal grain sizes for...
Three models for nonlocal electron thermal transport are here compared against Vlasov-Fokker-Planck (VFP) codes to assess their accuracy in situations relevant both inertial fusion hohlraums and tokamak scrape-off layers. The tested (i) a moment-based approach using an eigenvector integral closure (EIC) originally developed by Ji, Held Sovinec; (ii) the non-Fourier Landau-fluid (NFLF) model of Dimits, Joseph Umansky; (iii) Schurtz, Nicola\"i Busquet's multigroup diffusion (SNB). We find that...
This article constructs a fractal interpolation function, also referred to as $\alpha$-fractal using Suzuki-type generalized $\varphi$-contraction mappings (STGPC). The STGPC is generalization of mappings. process constructing functions the detailed, and examples are given. FIF has broad applications in data analysis, finance price prediction. We have included case study analyzing volatility spinach Azadpur vegetable market New Delhi. analysis gives unique perspective on understanding...
This paper summarizes the results of detailed, capsule-only simulations a set high foot implosion experiments conducted on National Ignition Facility (NIF). These span range ablator thicknesses, laser powers, and energies, modeling these as is important to assess whether simulation model can reproduce trends seen experimentally parameters were varied. Two-dimensional (2D) have been run including number effects—both nominal off-nominal—such hohlraum radiation asymmetries, surface roughness,...
A series of indirectly driven capsule implosions has been performed on the National Ignition Facility to assess relative contributions ablation-front instability growth vs. fuel compression implosion performance. Laser pulse shapes for both low and high-foot pulses were modified vary adiabat, separately controllably. Three principal conclusions are drawn from this study: (1) It is shown that reducing in low-foot results a substantial (3-10X) increase neutron yield with no loss compression....
Computer simulations of high energy density science experiments are computationally challenging, consisting multiple physics calculations including radiation transport, hydrodynamics, atomic physics, nuclear reactions, laser–plasma interactions, and more. To simulate inertial confinement fusion (ICF) at fidelity, each these should be as detailed possible. However, this quickly becomes too expensive even for modern supercomputers, thus many simplifying assumptions made to reduce the required...
Implosions of Hohlraum-driven double shell targets as an alternative inertial confinement fusion concept are underway at the National Ignition Facility. The system relies on a series energy transfer processes starting from thermal x-ray absorption by outer shell, followed collisional kinetic to heavy metal inner and finally, conversion internal deuterium-tritium fuel. During each these stages, low-mode asymmetries can act reduce ideal efficiency degrading performance. Mechanisms, such hard...
Simulating solidification in metals at high pressure: The drive to petascale computing, Frederick H Streitz, James N Glosli, Mehul V Patel, Bor Chan, Robert K Yates, Bronis R de Supinski, Sexton, John A Gunnels
Steady progress is being made in inertial confinement fusion experiments at the National Ignition Facility (NIF). Nonetheless, substantial further still needed to reach ultimate goal of ignition. Closing remaining gap will require either improving quality current implosions, increasing implosion scale (and correspondingly energy delivered by NIF), or some combination two. But how much an improvement required ignition? To reliably answer this question, accurate understanding and past first...
We have found that radiation-hydrodynamic calculations use the high flux model assumptions [1] can accurately predict radiation drive produced by a laser-heated hohlraum under certain conditions, but not over broad range of parameters (pulse energy, gas fill density, case-to-capsule ratio). In particular, is accurate for ∼7 ns long laser pulses used to implode capsules with density carbon (HDC) ablators in hohlraums helium densities 0-0.6 mg/cc. By systematically varying from 0 1.6 mg/cc we...
We report the preparation and characterization of self-assembled monolayers (SAMs) derived from adsorption partially fluorinated hexadecanethiols (CF3(CF2)n-1(CH2)mSH; n = 2, 4, 6, 8; + m 16) onto surface gold. The quality SAMs, as measured by electrochemical impedance spectroscopy, was found to be sensitive solvent used SAMs prepared in dichloromethane exhibited higher resistances lower capacitances than those liquid CO2. extent fluorination observed influence wettability, structure,...
The effects of including rotational degrees freedom on helium solvation densities in molecule-doped clusters are investigated for a variety molecules. Helium and cluster energetics calculated with diffusion Monte Carlo methods. rotationally induced changes the density distributions examined quantified theoretical estimator applicable to molecules arbitrary symmetry. This analysis leads discussion adiabatic following molecular rotation solvating environment. We make detailed comparative study...
Tailored, high-flux, multi-keV x-ray sources are desirable for studying interactions with matter various civilian, space and military applications. For this study, we focus on designing an efficient laser-driven non-local thermodynamic equilibrium 3–5 keV source from photon-energy-matched Ar K-shell Ag L-shell targets at sub-critical densities (∼nc/10) to ensure supersonic, volumetric laser heating minimal losses kinetic energy, thermal x rays laser-plasma instabilities. Using Hydra, a...
A new set of capabilities has been implemented in the HYDRA 2D/3D multiphysics inertial confinement fusion simulation code. These include a Monte Carlo particle transport library. It models neutrons, gamma rays and light ions, as well products they generate from nuclear coulomb collisions. allows accurate simulations diagnostic signatures capsule implosions. We apply it to here 3D National Ignition Facility (NIF) ignition which full solid angle. This contains severely rough ablator...