Bulletin of the American Physical Society
18th Biennial Intl. Conference of the APS Topical Group on Shock Compression of Condensed Matter held in conjunction with the 24th Biennial Intl. Conference of the Intl. Association for the Advancement of High Pressure Science and Technology (AIRAPT)
Volume 58, Number 7
Sunday–Friday, July 7–12, 2013; Seattle, Washington
Session L2: HM High Energy Density Materials I |
Hide Abstracts |
Chair: Gilbert Collins, Lawrence Livermore National Laboratory Room: Grand Ballroom II |
Tuesday, July 9, 2013 3:30PM - 4:00PM |
L2.00001: Ramp Compression of materials to high-pressure low-temperature states Invited Speaker: Raymond Smith The thermodynamics of compression are typically examined under isothermal conditions or with shock waves, where compressions are limited by the achievable pressure or dissipative heating, respectively. A relatively new dynamic compression technique, ramp compression, enables the adiabatic compression of matter with reduced dissipative heating as compared to shock compression and potentially allows the exploration of solids to the extreme densities expected to exist in the deepest interiors of giant planets. Ramp compression is however unstable relative to a shock because sound velocities typically increase with pressure. Therefore, to ramp compress matter into the multi-Mbar pressure regime, the pressure-loading history must be gentle enough to avoid shock formation, while sufficiently intense to achieve high pressures, constraints that until now were out of reach for laboratory experiments. I will describe ramp compression experiments on the NIF laser in which the stress-density of diamond and Fe were determined to peak pressures of 50Mbar and 8Mbar, respectively. I will also present preliminary data from the new NIF x-ray diffraction platform. [Preview Abstract] |
Tuesday, July 9, 2013 4:00PM - 4:30PM |
L2.00002: Strongly Coupled Plasma Shock Compression Invited Speaker: Vladimir Fortov The behavior of matter at extremely high pressures is of high principal interest for understanding the structure and evolution of astrophysical objects and many energy, nuclear and chemical technologies. Dynamics methods of generation of extremely high pressures in dense plasma, based on the compression and nonreversible heating of matter in intensive shock waves and waves of adiabatic discharge, are considered. To generate shock waves in the megabar pressure range the cylindrical and spherical condensed high explosives, laser and corpuscular beams, high velocity impacts, and soft X-rays were used. The highly time-resolved diagnostics of the extreme states of plasma were carried out with differential laser indicators of velocity, fast acting electron-optical transducers, pyrometers, and high-speed spectrometers equipped with the electron-optical transmission lines. The experimental data obtained and the physical models of behavior of plasma at extremely high pressures, temperatures and deformation rates are discussed. These are the metallization and dielectrization of strongly compressed matter, high temperature thermodynamics and phase transitions, deformation of energy spectrum of compressed atoms and strength and elastic-plastic phenomena, kinetics of phase transitions. We analyzed the shear viscosity of matter as an indicator of particles correlations in a broad region of parameters from Plank's scale to laboratory conditions. Wide-range semi-empirical equations of state and models are constructed, which were used for multidimensional numerical simulation of pulsed high-energy processes. [Preview Abstract] |
Tuesday, July 9, 2013 4:30PM - 5:00PM |
L2.00003: Structure Measurements of Highly Compressed Aluminum using X-Ray Thomson Scattering Invited Speaker: Tammy Ma X-ray Thomson scattering (XRTS) is a powerful technique to characterize materials in the challenging warm dense matter regime. In addition, XRTS measurements enable the benchmarking of dense plasma models and provide validation for EOS. Spectrally, angularly, and temporally resolved XRTS has been used to probe highly compressed aluminum (3x solid density) with 18 keV x-rays. The measured elastic scattering feature shows a well-pronounced correlation characteristic of the warm dense matter state. For the first time, the measurements of the scattering are precise enough to distinguish between theoretical models for the ion structure and show that screening effects must be accounted for in order to fit the shape and absolute intensity of the data. This further demonstrates the capability of XRTS to resolve the ion-ion correlation for an accurate measurement of compression. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. [Preview Abstract] |
Tuesday, July 9, 2013 5:00PM - 5:15PM |
L2.00004: X-ray Thomson scattering of warm dense matter on the Z-accelerator Tommy Ao, Eric Harding, James Bailey, Michael Desjarlais, Stephanie Hansen, Raymond Lemke, Gregory Rochau, Daniel Sinars, Ian Smith, Marcus Knudson, Joseph Reneker, Matthew Kernaghan, Gianluca Gregori Experiments on the Z-accelerator have demonstrated the ability to produce warm dense matter (WDM) states with unprecedented uniformity, duration, and size. Significant progress to combine x-ray Thomson scattering (XRTS), a powerful diagnostic for WDM, with the extreme environments created at Z has been accomplished. The large Z current is used to magnetically launch Al flyers to impact CH$_{2}$ foam (0.12 g/cm$^{3})$. The uniformly-shocked CH$_{2}$ volume is 5-10 mm$^{3}$, and the steady shock phase lasts 10-100 ns, which are roughly 1500 {\&} 100 times larger, respectively, than typical laser shocked samples. The Z-Beamlet laser irradiates a 5 $\mu $m thick Mn foil near the load to generate 6.181 keV Mn-He-$\alpha $ x-rays that penetrate into the WDM state and scatter from it. A new high sensitivity x-ray scattering spherical spectrometer (XRS$^{3})$ with both high spatial ($\sim$75 $\mu $m) and spectral ($E/\Delta E$ $\sim$ 1500) resolution is fielded that enables benchmark quality data by simultaneously measuring x-rays scattered from shocked and ambient regions of the CH$_{2}$ foam, and the Mn x-ray source. [Preview Abstract] |
Tuesday, July 9, 2013 5:15PM - 5:30PM |
L2.00005: Cylindrically Convergent Implosions of Metal Liners for Driving an Isentropic Compression in Cryogenic Deuterium Marcus Weinwurm, Simon Bland, Jeremy Chittenden In order to take advantage of geometrical convergence, we investigated a method, where a Beryllium liner drives a cylindrical shockless compression in a cryogenic Deuterium fill. The metal liner acts as a current carrier as well as a pressure boundary to the fill. The required driving pressure was obtained through a fictitious flow (FF) simulation [Clark, D.S. and Tabak, M. (2007) Nuclear Fusion 47, 1147]. A current model, which can recreate the FF compression inside the liner by shaping the current pulse, is then introduced. This method allows efficient compression of Deuterium at low entropy, enabling the recreation of conditions present in the interior of gas giants and potentially the observation of a transition into a metallic state. Two-dimensional simulations show that thick liners remain robust to the growth of Rayleigh-Taylor instabilities, suggesting that cylindrical isentropic ramp compression is a promising scheme for extending Deuterium's experimentally measured Equation of State. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700