A5067419292- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- High-pressure geophysics and materials
- Combustion and Detonation Processes
- Fusion materials and technologies
- Nuclear Physics and Applications
- Particle Dynamics in Fluid Flows
- Energetic Materials and Combustion
- Cold Fusion and Nuclear Reactions
- Magnetic confinement fusion research
- Fluid Dynamics and Turbulent Flows
- Computational Fluid Dynamics and Aerodynamics
- Micro and Nano Robotics
- Nuclear Materials and Properties
- Nuclear reactor physics and engineering
- Engineering and Material Science Research
- Microfluidic and Bio-sensing Technologies
- Laser Design and Applications
- Polymer Foaming and Composites
- Molecular Communication and Nanonetworks
- Astro and Planetary Science
- Radioactive contamination and transfer
- Atomic and Molecular Physics
- Plasma and Flow Control in Aerodynamics
Los Alamos National Laboratory
2016-2025
Computational Physics (United States)
2019-2024
Lawrence Livermore National Laboratory
2017-2022
University of Rochester
2019-2022
Energetics (United States)
2019-2022
ORCID
2021
University of Michigan
2008-2019
Oncor (United States)
2019
Imperial College London
2019
Massachusetts Institute of Technology
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...
The viscosity of a suspension swimming bacteria is investigated analytically and numerically. We propose simple model that allows for efficient computation large number bacteria. Our calculations show long-range hydrodynamic interactions, intrinsic to self-locomoting objects in viscous fluid, result dramatic reduction the effective viscosity. In agreement with experiments on suspensions Bacillus subtilis, we related onset large-scale collective motion due interactions between swimmers....
We derive the effective viscosity of dilute suspensions swimming bacteria from microscopic details interaction an elongated body with background flow. An individual bacterium propels itself forward by rotating its flagella and reorients randomly tumbling. Due to bacterium's asymmetric shape, interactions a prescribed generic (such as planar shear or straining) flow cause preferentially align in directions which self-propulsion produces significant reduction viscosity, agreement recent...
In implicit large-eddy simulation (ILES), energy-containing large scales are resolved, and physics capturing numerics used to spatially filter out unresolved implicitly model subgrid scale effects. From an applied perspective, it is highly desirable estimate a characteristic Reynolds number (Re)---and therefore relevant effective viscosity---so that the impact of resolution on predicted flow quantities their macroscopic convergence can usefully be characterized. We argue in favor obtaining...
In this paper, we present the results of high-resolution simulations implosion high-convergence layered indirect-drive inertial confinement fusion capsules type fielded on National Ignition Facility using xRAGE radiation-hydrodynamics code. order to evaluate suitability model such experiments, benchmark simulation against available experimental data, including shock-timing, shock-velocity, and shell trajectory as well hydrodynamic instability growth rates. We discuss code improvements that...
Abstract The injection and mixing of contaminant mass into the fuel in inertial confinement fusion (ICF) implosions is a primary factor preventing ignition. ICF experiments have recently achieved an alpha-heating regime, which self-heating dominant source yield, by reducing susceptibility to instabilities that inject this mass. We report results unique separated reactants implosion studying pre-mixed as well detailed high-resolution three-dimensional simulations are good agreement with...
High-yield implosions on the National Ignition Facility rely maintaining low entropy in deuterium–tritium fuel, quantified by its adiabat, order to efficiently couple energy hot spot through high compression of fuel layer. We present very-high-resolution xRAGE simulation results that study impacts interfacial mixing and jetting materials due surface defects, defects internal interfaces, voids, engineering features layer compression. Defects voids are typically neglected implosion simulations...
High energy density physics (HEDP) and inertial confinement fusion (ICF) research typically relies on computational modeling using radiation-hydrodynamics codes in order to design experiments understand their results. These tools, turn, rely numerous charged particle transport relaxation coefficients account for laser absorption, viscous dissipation, mass transport, thermal conduction, electrical non-local ion (including product) electron magnetohydrodynamics, multi-ion-species...
Ignition on the National Facility (NIF) provides a novel opportunity to evaluate past data identify signatures of capsule failure mechanisms. We have used new simulations high-yield implosions as well some from studies in order unique different ignition mechanisms: jetting due presence voids or defects, fill tube, interfacial mixing instabilities plasma transport, radiative cooling contaminant hot spot, long-wavelength drive asymmetry, and preheat. Many these mechanisms exhibit trajectories...
The first cryogenic deuterium and deuterium-tritium liquid layer implosions at the National Ignition Facility (NIF) demonstrate D2 DT inertial confinement fusion (ICF) that can access a low-to-moderate hot-spot convergence ratio (12<CR<25). Previous ICF experiments NIF utilized high (CR>30) ice implosions. Although CR is desirable in an idealized 1D sense, it amplifies deleterious effects of asymmetries. To date, these asymmetries prevented achievement ignition are major cause...
We present results from the comparison of high-resolution three-dimensional (3D) simulations with data implosions inertial confinement fusion capsules separated reactants performed on OMEGA laser facility. Each capsule, referred to as a “CD Mixcap,” is filled tritium and has polystyrene (CH) shell deuterated (CD) layer whose burial depth varied. In these implosions, reactions between deuterium ions can occur only in presence atomic mix gas fill material. The feature accurate models for all...
We report on a high convergence ratio liquid layer capsule implosion performed the National Ignition Facility and contrast it to two previously reported layered implosions, in order better understand how design impacts hydrodynamic stability properties of implosions. Three implosions were with similar ratios, fuel entropy, in-flight aspect unablated shell mass; these qualities are important for determining stability. Nevertheless, while exhibited robustness asymmetries, including our recent...
Abstract Indirect drive converts high power laser light into x-rays using small high- Z cavities called hohlraums. X-rays generated at the hohlraum walls a capsule filled with deuterium–tritium (DT) fuel to fusion conditions. Recent experiments have produced yields exceeding 50 kJ where alpha heating provides ~3× increase in yield over PdV work. Closing gaps toward ignition is challenging, requiring optimization of target/implosions and extract maximum energy. The US program has...
We present a mathematical proof of Einstein's formula for the effective viscosity dilute suspension rigid neutrally buoyant spheres when are centered on vertices cubic lattice. keep size container finite in limit and consider boundary effects. is recovered as first-order asymptotic expansion volume fraction. To rigorously justify this expansion, we obtain an explicit upper lower bound viscosity. A found using energy methods reminiscent work Keller et al. An follows by obtaining estimate...
The authors present an improved strategy for performing simulations of inertial confinement fusion. commonly used beginning the simulation in two dimensions and later mapping it to three has significant shortcomings. demonstrate that introducing suitable nonuniform perturbations at time produces results good agreement with purely three-dimensional available experimental data.
We investigate a strategy for benchmarking Reynolds-averaged Navier–Stokes (RANS) models by comparing moments extracted from averaged large eddy simulation (LES) data and those predicted directly RANS. consider the Besnard–Harlow–Rauenzahn (BHR) RANS approach designed variable-density compressible flows, which has been previously applied to wide variety of turbulence problems interest. focus on model's ability predict relevant shock-driven material mixing. A prototypical inverse chevron...
We perform two-dimensional simulations of strongly–driven compressible Rayleigh–Taylor and Kelvin–Helmholtz instabilities with without plasma transport phenomena, modeling species diffusion, viscosity in order to determine their effects on the growth hydrodynamic instabilities. Simulations are performed hydrodynamically similar boxes varying sizes, ranging from 1 μm cm scale at which become important. Our results suggest that these noticeable when box size is approximately 100 μm, they...
The wetted foam capsule design for inertial confinement fusion capsules, which includes a layer with deuterium-tritium liquid, enables layered implosions wide range of hot-spot convergence ratios (CR) on the National Ignition Facility. We present full-scale that demonstrates high gain in one-dimensional simulations. In these simulations, increasing ratio leads to an improved yield due higher temperatures and increased fuel areal density. High-resolution two-dimensional simulations this are...
Hohlraums are hollow cylindrical cavities with high-Z material walls used to convert laser energy into uniform x-ray radiation drives for inertial confinement fusion capsule implosions and high density physics experiments. Credible computational modeling of hohlraums requires detailed coupling physics, hydrodynamics, transport, heat atomic physics. We report on improvements Los Alamos National Laboratory's xRAGE radiation-hydrodynamics code in order enable hohlraum modeling. xRAGE's Eulerian...
After decades of research, recent laser-driven inertial fusion experiments have demonstrated rapid progress toward achieving thermonuclear ignition using capsule designs with cryogenic fuel layers. The physics for these layered capsules involves a complex interplay between the dynamically forming hot spot and dense surrounding fuel. Using analytic theory numerical simulations, we demonstrate that mass ablation rate into depends sensitively upon temperature fuel, resulting in ablative inflows...
A multi-laboratory collaborative effort is currently exploring the feasibility of laser direct drive liquid deuterium–tritium (DT) wetted foam inertial confinement fusion concepts being considered for novel neutron sources on National Ignition Facility (NIF) laser. In contrast to indirect approach that recently demonstrated ignition in laboratory, these also offer potential multi-MJ yields but with less damaging drives, improved robustness target and imperfections, enhanced facility fielding...
Double shell targets are an alternative ignition platform for inertial confinement fusion. One design consideration double is the choice of inner material to help trap radiation emitted by hot fuel aid ignition. Materials such as molybdenum and tungsten interest layer targets. While has a lower density that could inhibit instability growth allow radiography code benchmarking, higher provide more compression confinement. These tradeoffs have been explored using optimized designs each...