Publications

Results 101–125 of 2,290

Search results

Jump to search filters

Hugoniot, sound speed, and phase transitions of single-crystal sapphire for pressures 0.2-2.1 TPa

Physical Review B

McCoy, C.A.; Laros, James H.; Knudson, Marcus D.; Desjarlais, Michael P.; Duwal, Sakun D.; Root, Seth R.

Sapphire (Al2O3) is a major constituent of the Earth's mantle and has significant contributions to the field of high-pressure physics. Constraining its Hugoniot over a wide pressure range and identifying the location of shock-driven phase transitions allows for development of a multiphase equation of state and enables its use as an impedance-matching standard in shock physics experiments. Here, we present measurements of the principal Hugoniot and sound velocity from direct impact experiments using magnetically launched flyers on the Z machine at Sandia National Laboratories. The Hugoniot was constrained for pressures from 0.2-2.1 TPa and a four-segment piecewise linear shock-velocity-particle-velocity fit was determined. First-principles molecular dynamics simulations were conducted and agree well with the experimental Hugoniot. Sound-speed measurements identified the onset of melt between 450 and 530 GPa, and the Hugoniot fit refined the onset to 525±13 GPa. A phase diagram which incorporates literature diamond-anvil cell data and melting measurements is presented.

More Details
TYPE Conference Poster YEAR 2023
DOIOSTIScopus

Investigations of Farm-to-Farm Interactions and Blockage Effects from AWAKEN Using Large-Scale Numerical Simulations

Cheung, Lawrence C.; Blaylock, Myra L.; Brown, Kenneth B.; deVelder, Nathaniel d.; Herges, Thomas H.; Houck, Daniel; Laros, James H.; Maniaci, David C.; Sakievich, Philip S.; Brazell, Michael; Churchfield, Matthew; Hamilton, Nicholas; Rybchuk, Alex; Sprague, Michael; Thedin, Regis; Kaul, Colleen; Rai, Raj

Abstract not provided.

More Details
TYPE Conference Presenation YEAR 2023
DOIOSTI

Demonstration of improved laser preheat with a cryogenically cooled magnetized liner inertial fusion platform

Review of Scientific Instruments

Harvey-Thompson, Adam J.; Geissel, Matthias G.; Crabtree, Jerry A.; Weis, Matthew R.; Gomez, Matthew R.; Fein, Jeffrey R.; Laros, James H.; Ampleford, David A.; Awe, Thomas J.; Chandler, Gordon A.; Hansen, Stephanie B.; Jennings, Christopher A.; Knapp, Patrick K.; Kimmel, Mark W.; Mangan, Michael M.; Peterson, Kyle J.; Porter, John L.; Rochau, G.A.; Ruiz, Daniel E.; Hanson, Joseph C.; Harding, Eric H.; Perea, L.; Robertson, Grafton K.; Shores, Jonathon S.; Slutz, Stephen A.; Smith, G.E.; Speas, Christopher S.; Yager-Elorriaga, David A.; York, Adam Y.

We report on progress implementing and testing cryogenically cooled platforms for Magnetized Liner Inertial Fusion (MagLIF) experiments. Two cryogenically cooled experimental platforms were developed: an integrated platform fielded on the Z pulsed power generator that combines magnetization, laser preheat, and pulsed-power-driven fuel compression and a laser-only platform in a separate chamber that enables measurements of the laser preheat energy using shadowgraphy measurements. The laser-only experiments suggest that ∼89% ± 10% of the incident energy is coupled to the fuel in cooled targets across the energy range tested, significantly higher than previous warm experiments that achieved at most 67% coupling and in line with simulation predictions. The laser preheat configuration was applied to a cryogenically cooled integrated experiment that used a novel cryostat configuration that cooled the MagLIF liner from both ends. The integrated experiment, z3576, coupled 2.32 ± 0.25 kJ preheat energy to the fuel, the highest to-date, demonstrated excellent temperature control and nominal current delivery, and produced one of the highest pressure stagnations as determined by a Bayesian analysis of the data.

More Details
TYPE Journal Article YEAR 2023
DOIOSTIScopus

Data-driven assessment of magnetic charged particle confinement parameter scaling in magnetized liner inertial fusion experiments on Z

Physics of Plasmas

Laros, James H.; Mannion, Owen M.; Ruiz, Daniel E.; Jennings, Christopher A.; Knapp, Patrick K.; Gomez, Matthew R.; Harvey-Thompson, Adam J.; Weis, Matthew R.; Slutz, Stephen A.; Ampleford, David A.; Beckwith, Kristian B.

In magneto-inertial fusion, the ratio of the characteristic fuel length perpendicular to the applied magnetic field R to the α-particle Larmor radius Q α is a critical parameter setting the scale of electron thermal-conduction loss and charged burn-product confinement. Using a previously developed deep-learning-based Bayesian inference tool, we obtain the magnetic-field fuel-radius product B R ∝ R / Q α from an ensemble of 16 magnetized liner inertial fusion (MagLIF) experiments. Observations of the trends in BR are consistent with relative trade-offs between compression and flux loss as well as the impact of mix from 1D resistive radiation magneto-hydrodynamics simulations in all but two experiments, for which 3D effects are hypothesized to play a significant role. Finally, we explain the relationship between BR and the generalized Lawson parameter χ. Our results indicate the ability to improve performance in MagLIF through careful tuning of experimental inputs, while also highlighting key risks from mix and 3D effects that must be mitigated in scaling MagLIF to higher currents with a next-generation driver.

More Details
TYPE Journal Article YEAR 2023
DOIOSTIScopus
Results 101–125 of 2,290
Results 101–125 of 2,290