A5027419685- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- Nuclear Physics and Applications
- High-pressure geophysics and materials
- Ion-surface interactions and analysis
- Cold Fusion and Nuclear Reactions
- Combustion and Detonation Processes
- X-ray Spectroscopy and Fluorescence Analysis
- Fusion materials and technologies
- Magnetic confinement fusion research
- Energetic Materials and Combustion
- High-Velocity Impact and Material Behavior
- Superconducting Materials and Applications
- Solar and Space Plasma Dynamics
- Computational Fluid Dynamics and Aerodynamics
- Particle accelerators and beam dynamics
- Engineering and Material Science Research
- Optical Polarization and Ellipsometry
- Atomic and Molecular Physics
- Radiation Therapy and Dosimetry
- Electromagnetic Launch and Propulsion Technology
- Spectroscopy and Laser Applications
- Diamond and Carbon-based Materials Research
- Advanced X-ray Imaging Techniques
General Atomics (United States)
2018-2024
Lawrence Livermore National Laboratory
2011-2024
Compound parabolic concentrator (CPC) targets are utilized at the National Ignition Facility Advanced Radiographic Capability (NIF-ARC) laser to enhance acceleration of electrons and production high energy photons, for durations 10 ps energies up 2.4 kJ. A large enhancement mean electron (>2 ×) photon brightness (>10×) is found with CPC compared flat targets. Using multiple diagnostic techniques different spatial locations scaling by gold activation data, spectra characterized...
High-resolution, high-energy X-ray backlighters are very active area of research for radiography experiments at the National Ignition Facility (NIF) [Miller et al., Nucl. Fusion 44, S228 (2004)], in particular those aiming obtaining Compton-scattering produced radiographs from cold, dense fuel surrounding hot spot. We report on to generate and characterize point-projection-geometry using short pulses advanced radiographic capability (ARC) [Crane J. Phys. 244, 032003 (2010); Di Nicola Proc....
The implosion efficiency in inertial confinement fusion depends on the degree of stagnated fuel compression, density uniformity, sphericity, and minimum residual kinetic energy achieved. Compton scattering-mediated 50--200 keV x-ray radiographs indirect-drive cryogenic implosions at National Ignition Facility capture dynamic evolution as it goes through peak revealing low-mode 3D nonuniformities thicker with lower than simulated. By differencing two taken different times during same...
This study investigated discrepancies between measured and simulated x-ray drive in Inertial Confinement Fusion (ICF) hohlraums at the National Ignition Facility (NIF). Despite advances radiation-hydrodynamic simulations, a consistent "drive deficit" remains. Experimentally ICF capsule bang-times are systematically 400-700 ps later than simulations predict. The Build-A-Hohlraum (BAH) campaign explored potential causes for this discrepancy by varying hohlraum features, including laser...
We have developed an experimental platform at the National Ignition Facility that employs colliding planar shocks to produce warm dense matter with uniform conditions and enable high-precision equation of state measurements. The uses simultaneous x-ray Thomson scattering radiography measure density, electron temperature, ionization in matter. is designed create a large volume plasma (approximately 700×700×150μm3) pressures approaching 100 Mbar minimize distribution volume, significantly...
Magnetizing a cryogenic deuterium–tritium (DT)-layered inertial confinement fusion (ICF) implosion can improve performance by reducing thermal conduction and improving DT-alpha in the hot spot. A room-temperature, magnetized indirect-drive ICF platform at National Ignition Facility has been developed, using high-Z, high-resistivity AuTa4 alloy as hohlraum wall material. Experiments show 2.5× increase deuterium–deuterium (DD) neutron yield 0.8-keV hot-spot temperature with application of 12-T...
Picosecond-scale laser–matter interactions using compound parabolic concentrators have demonstrated strongly relativistic ponderomotive effects with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo>∼</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>10</mml:mn> </mml:mrow> <mml:mo>×</mml:mo> </mml:math> increase in x-ray source brightness, positron production and multi-MeV proton acceleration versus flat targets, a marginally intensity laser.
Large laser facilities have recently enabled material characterization at the pressures of Earth and Super-Earth cores. However, temperature compressed materials has been largely unknown, or solely relied on models simulations, due to lack diagnostics under these challenging conditions. Here, we report temperature, density, pressure, local structure copper determined from extended x-ray absorption fine velocimetry up 1 Terapascal. These results nearly double highest pressure which reported...
The predicted implosion performance of deuterium-tritium fuel capsules in indirect-drive inertial confinement fusion experiments relies on precise calculations the x-ray drive laser-heated cavities (hohlraums). This requires accurate, spectrally dependent simulations laser to conversion efficiencies and absorption losses hohlraum wall. A set National Ignition Facility have identified a cause for long-standing "drive deficit" as overprediction gold emission at ∼2.5 keV nonlocal thermodynamic...
Achieving a symmetric implosion in National Ignition Facility indirect drive targets requires understanding and control of dynamic changes to the laser power transport hohlraum. We developed new experimental platform simultaneously visualize wall-plasma motion hohlraum are using it investigate correlations these measurements with imploded capsule symmetry. In series experiments where we made one single parameter variation, show value this developing an This also provides way evaluate...
Graded metal pushered single shell (PSS) capsules are predicted to be a viable alternative low-Z capsule indirect drive inertial confinement fusion (ICF) implosions for achieving high yields [MacLaren et al., Phys. Plasmas 28, 122710 (2021)]. The first experiments with Be/Cr-graded PSS indicate that the implementation of principle design feature, graded density inner layer, has succeeded in producing stable implosion performance agreement predictions. With 50% Cr concentration pusher, have...
Laser-driven Hohlraums filled with gas at lower densities (&lt;0.6 mg/cc) have higher efficiency compared to original ≥ 0.96 mg/cc fill because of reduced backscatter losses [Hall et al., Phys. Plasmas 24, 052706 (2017)]. However, using low-density longer drive required for adiabat implosions, and hence potentially inertial confinement fusion gain designs, has been challenging since the Hohlraum wall blow-off is less tamped, thus altering laser beam absorption regions symmetry. A series...
The high fuel capsule compression required for indirect drive inertial confinement fusion requires careful control of the X-ray symmetry throughout laser pulse. When outer cone beams strike hohlraum wall, plasma ablated off wall expands into and can alter both inner beam propagations hence especially at final stage To quantitatively understand motion, we developed a new experimental technique which visualizes expansion stagnation plasma. Details experiment spectrally selective x-ray imaging...
To benchmark the accuracy of models and improve predictive capability future experiments, National Ignition Facility requires measurements physical conditions inside inertial confinement fusion hohlraums. The ion temperature bulk motion velocity gas-filled regions hohlraum can be obtained by replacing helium tamping gas in with deuterium-tritium (DT) measuring Doppler broadening shift neutron spectrum produced nuclear reactions hohlraum. understand spatial distribution production hohlraum,...
High-energy-density laser facilities and advances in dynamic compression techniques have expanded access to material states the Terapascal regime relevant inertial confinement fusion, planetary science, geophysics. However, experimentally determining temperature these extreme conditions has remained a difficult challenge. Extended X-ray Absorption Fine Structure (EXAFS), referring modulations x-ray absorption above an edge from photoelectrons’ interactions with neighboring atoms, proven be...
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A new pulse power system is being developed with the goal of generating up to 40T seed magnetic fields for increasing fusion yield indirect drive inertial confinement (ICF) experiments on National Ignition Facility. This pulser located outside target chamber and delivers a current through coaxial cable bundle custom flex-circuit strip-lines integrated into cryogenic positioner. At target, passes multi-turn solenoid wrapped around hohlraum insulated Kapton coating. 11.33 uF capacitor, charged...