A5060400300- Laser-Plasma Interactions and Diagnostics
- High-pressure geophysics and materials
- Nuclear Physics and Applications
- Laser-induced spectroscopy and plasma
- Fusion materials and technologies
- Combustion and Detonation Processes
- Particle Dynamics in Fluid Flows
- Magnetic confinement fusion research
- X-ray Spectroscopy and Fluorescence Analysis
- Geophysics and Sensor Technology
- Advanced X-ray Imaging Techniques
- Atomic and Molecular Physics
- Magnetic and Electromagnetic Effects
- Traumatic Ocular and Foreign Body Injuries
- Laser-Matter Interactions and Applications
- Characterization and Applications of Magnetic Nanoparticles
- Ion-surface interactions and analysis
- Laser Design and Applications
Lawrence Livermore National Laboratory
2013-2024
General Atomics (United States)
2018-2024
Schafer Corporation (United States)
2018
We present the development of an experimental platform that can collect four frames x-ray diffraction data along a single line sight during laser-driven, dynamic-compression experiments at National Ignition Facility. The is comprised diagnostic imager built around ultrafast sensors with 2-ns integration time, custom target assembly serves also to shield imager, and 10-ns duration, quasi-monochromatic source produced by laser-generated plasma. demonstrate performance for Pb ramp compressed...
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...
In indirectly driven Inertial Confinement Fusion implosions conducted on the National Ignition Facility (NIF), imploding capsule is supported in a laser-heated radiation enclosure (called “hohlraum”) by pair of very thin (∼15–45 nm) plastic films (referred to as “tent”). Even though thickness these tents small fraction that spherical ablator (∼165 μm), both numerical simulations well experiments indicate this support mechanism results large areal density (ρR) perturbation surface at contact...
Hydrodynamic instability growth of capsule support membranes (or “tents”) has been recognized as one the major contributors to performance degradation in high-compression plastic implosions at National Ignition Facility (NIF) [E. M. Campbell et al., AIP Conf. Proc. 429, 3 (1998)]. The capsules were supported by tents because nominal 10-μm diameter fill tubes not strong enough themselves indirect-drive on NIF. After it was that had a significant impact implosion's stability, new alternative...
AbstractAbstractCapsule ablators are precision hollow spheres used in inertial confinement fusion targets high-peak-power laser systems such as the National Ignition Facility. These capsules have high surface-quality requirements, and hence a full surface microscopic mapping system has been developed to characterize them. The capsule-fill-tube-assembly combines confocal surface-profiling microscope with nine-axis, high-precision stage provide quantitative three-dimensional data over entire...
An x-ray Fresnel diffractive radiography platform was designed for use at the National Ignition Facility. It will enable measurements of micron-scale changes in density gradients across an interface between isochorically heated warm dense matter materials, evolution which is driven primarily through thermal conductivity and mutual diffusion. We 4.75 keV Ti K-shell emission to heat a 1000 μm diameter plastic cylinder, with central 30 channel filled liquid D2, up 8 eV. This leads cylindrical...
We present the results of experiments to produce a 10 ns-long, quasi-monochromatic x-ray source. This effort is needed support time-resolved diffraction (XRDt) measurements phase transitions during laser-driven dynamic compression at National Ignition Facility. To record XRDt as they occur, we use high-speed (∼1 ns) gated hybrid CMOS detectors, which multiple frames data over timescale few tens ns. Consequently, make effective these imagers, needs source be narrow in energy and uniform time...
This study investigates methods to optimize quasi-monochromatic, ∼10 ns long x-ray sources (XRS) for time-resolved diffraction measurements of phase transitions during dynamic laser compression at the National Ignition Facility (NIF). To support this, we produce continuous and pulsed XRS by irradiating a Ge foil with NIF lasers achieve an intensity 2 × 1015 W/cm2, optimizing laser-to-x-ray conversion efficiency. Our source is dominated He-α line emission. We discuss maintain uniform ns,...
Because isolated contaminants on an inertial confinement fusion (ICF) ablator capsule can lead to undesirable instabilities during implosion, it is critical remove particles from the surface of plastic capsules prior target assembly. Current National Ignition Facility (NIF) specifications require that contain no larger than 30 μm3. We have developed a solvent-based cleaning process in which combination wetting and hydrodynamic forces used dislodge, entrain, NIF ICF ablators. The was...
We investigate the feasibility of producing x-ray sources over timescales relevant to support time-resolved diffraction (XRDt) measurements during laser-driven dynamic compression experiments at National Ignition Facility (NIF) [1] . XRDt probes atomic structure in-situ transformations extreme thermodynamic conditions. To record XRD phase transitions as they occur, we use high-speed (~1 ns) gated hybrid CMOS (hCMOS) imagers [2] , which provide multiple frames data a timescale few tens ns....