A. V. Hamza
A5008404499- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Ion-surface interactions and analysis
- High-pressure geophysics and materials
- Diamond and Carbon-based Materials Research
- Laser-Matter Interactions and Applications
- Electron and X-Ray Spectroscopy Techniques
- Atomic and Molecular Physics
- Metal and Thin Film Mechanics
- Nanoporous metals and alloys
- Catalytic Processes in Materials Science
- Advanced Chemical Physics Studies
- Fusion materials and technologies
- Nuclear Physics and Applications
- Integrated Circuits and Semiconductor Failure Analysis
- Fullerene Chemistry and Applications
- Combustion and Detonation Processes
- Microstructure and mechanical properties
- Nuclear Materials and Properties
- Graphene research and applications
- Electrocatalysts for Energy Conversion
- Mass Spectrometry Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Energetic Materials and Combustion
- nanoparticles nucleation surface interactions
Lawrence Livermore National Laboratory
2012-2024
Heriot-Watt University
2024
General Atomics (United States)
2006-2018
Schafer Corporation (United States)
2018
Los Alamos National Laboratory
2012-2017
University of Rochester
2012-2017
Energetics (United States)
2012-2017
University of Nevada, Reno
2017
Computational Sciences (United States)
2017
Prism Computational Sciences (United States)
2017
Point design targets have been specified for the initial ignition campaign on National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 443, 2841 (2004)]. The contain D-T fusion fuel in an ablator of either CH with Ge doping, or Be Cu. These shells are imploded a U Au hohlraum peak radiation temperature set between 270 300 eV. Considerations determining point include laser-plasma interactions, hydrodynamic instabilities, laser operations, target fabrication....
Indirect-drive hohlraum experiments at the National Ignition Facility have demonstrated symmetric capsule implosions unprecedented laser drive energies of 0.7 megajoule. One hundred and ninety-two simultaneously fired beams heat ignition-emulate hohlraums to radiation temperatures 3.3 million kelvin, compressing 1.8-millimeter-diameter capsules by soft x-rays produced hohlraum. Self-generated plasma optics gratings on either end tune power distribution in hohlraum, which produces a x-ray as...
The National Ignition Facility (NIF) at Lawrence Livermore Laboratory includes a precision laser system now capable of delivering 1.8 MJ 500 TW 0.35-μm light to target. NIF has been operational since March 2009. A variety experiments have completed in support NIF's mission areas: national security, fundamental science, and inertial fusion energy. capabilities infrastructure are place its missions with nearly 60 X-ray, optical, nuclear diagnostic systems. primary goal the Campaign (NIC) on...
We study the evolution of lattice defects in single-crystal ZnO bombarded with 60-keV ${}^{28}\mathrm{Si}$ and 300-keV ${}^{197}\mathrm{Au}$ ions at 77 300 K. To characterize ion-beam-produced structural defects, we use a combination Rutherford backscattering/channeling (RBS/C) spectrometry, cross-sectional transmission electron microscopy (XTEM), x-ray photoelectron spectroscopy, atomic force microscopy. Results show that exhibits strong dynamic annealing, even high-dose bombardment heavy...
Colloidal solutions of metal nanoparticles are currently among the most studied substrates for sensors based on surface-enhanced Raman scattering (SERS). However, such often suffer from not being cost-effective, reusable, or stable. Here, we develop nanoporous Au as a highly active, tunable, stable, biocompatible, and reusable SERS substrate. Nanoporous is prepared by facile process free corrosion AgAu alloys followed annealing. Results show that nanofoams with average pore widths ∼250nm...
A new compression technique, which enables the study of solids into TPa regime, is described and used to ramp (or quasi-isentropically) compress diamond a peak pressure 1400 GPa. Diamond stress versus density data are reported 800 GPa suggest that phase stable has significant material strength up at least this level. Data presented here highest pressures by more than factor 5 highest-pressure solid equation-of-state ever reported.
Ignition requires precisely controlled, high convergence implosions to assemble a dense shell of deuterium-tritium (DT) fuel with ρR>∼1 g/cm2 surrounding 10 keV hot spot ρR ∼ 0.3 g/cm2. A working definition ignition has been yield ∼1 MJ. At this the α-particle energy deposited in would have ∼200 kJ, which is already ∼10 × more than kinetic typical implosion. The National Campaign includes low dudded layers study and optimize hydrodynamic assembly diagnostics rich environment. mixture...
Capsule performance optimization campaigns will be conducted at the National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, 228 (2004)] to substantially increase probability of ignition. The experimentally correct for residual uncertainties in implosion hohlraum physics used our radiation-hydrodynamic computational models using a variety ignition capsule surrogates before proceeding cryogenic-layered implosions experiments. quantitative goals technique...
Mixing of plastic ablator material, doped with Cu and Ge dopants, deep into the hot spot ignition-scale inertial confinement fusion implosions by hydrodynamic instabilities is diagnosed x-ray spectroscopy on National Ignition Facility. The amount hot-spot mix mass determined from absolute brightness emergent K-shell emission. dopants placed at different radial locations in show ablation-front instability primarily responsible for mix. Low neutron yields between 34(-13,+50) ng 4000(-2970,+17...
High Density Carbon (HDC) is a leading candidate as an ablator material for Inertial Confinement Fusion (ICF) capsules in x-ray (indirect) drive implosions. HDC has higher density (3.5 g/cc) than plastic (CH, 1 g/cc), which results thinner with larger inner radius given capsule scale. This leads to absorption and shorter laser pulses compared equivalent CH designs. paper will describe series of experiments carried out examine the feasibility using both gas filled hohlraums lower density,...
Measurements have been made of the in-flight dynamics imploding capsules indirectly driven by laser energies 1–1.7 MJ at National Ignition Facility [Miller et al., Nucl. Fusion 44, 228 (2004)]. These experiments were part Campaign [Landen Phys. Plasmas 18, 051002 (2011)] to iteratively optimize inputs required achieve thermonuclear ignition in laboratory. Using gated or streaked hard x-ray radiography, a suite ablator performance parameters, including time-resolved radius, velocity, mass,...
Capsule implosions on the National Ignition Facility (NIF) [Lindl et al., Phys. Plasmas 11, 339 (2004)] are underway with goal of compressing deuterium-tritium (DT) fuel to a sufficiently high areal density (ρR) sustain self-propagating burn wave required for fusion power gain greater than unity. These driven carefully tailored sequence four shock waves that must be timed very precision in order keep DT low adiabat. Initial experiments measure strength and relative timing these shocks have...
Recent experiments on the National Ignition Facility [M. J. Edwards et al., Phys. Plasmas 20, 070501 (2013)] demonstrate that utilizing a near-vacuum hohlraum (low pressure gas-filled) is viable option for high convergence cryogenic deuterium-tritium (DT) layered capsule implosions. This made possible by using dense ablator (high-density carbon), which shortens drive duration needed to achieve convergence: measured 40% higher efficiency than typical gas-filled hohlraums, requires less laser...
Ignition of an inertial confinement fusion (ICF) target depends on the formation a central hot spot with sufficient temperature and areal density. Radiative conductive losses from can be enhanced by hydrodynamic instabilities. The concentric spherical layers current National Facility (NIF) ignition targets consist plastic ablator surrounding thin shell cryogenic thermonuclear fuel (i.e., hydrogen isotopes), vapor filling interior volume [S. W. Haan et al., Phys. Plasmas 18, 051001 (2011)]....
Porosity generally embrittles ceramics. In contrast to such expectations, this report demonstrates that an effective fracture strain of nanoporous silica aerogels increases with increasing porosity. At ultralow relative densities <0.5%, monoliths start exhibiting super-compressible deformation strains >50%. This is attributed consequences increase in the aspect ratio ligaments decreasing density.
Ignition experiments have shown an anomalous susceptibility to hydrodynamic instability growth. To help understand these results, the first growth measurements in indirectly driven implosions on National Facility were performed at ignition conditions with peak radiation temperatures up ∼300 eV. Plastic capsules two-dimensional preimposed, sinusoidal outer surface modulations of initial wavelengths 240 (corresponding a Legendre mode number 30), 120 (mode 60), and 80 μm 90) imploded by using...