Bulletin of the American Physical Society
57th Annual Meeting of the APS Division of Plasma Physics
Volume 60, Number 19
Monday–Friday, November 16–20, 2015; Savannah, Georgia
Session CO4: Equation of State |
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Chair: Luke Shulenburger, Sandia National Laboratories Room: 105/106 |
Monday, November 16, 2015 2:00PM - 2:12PM |
CO4.00001: Extreme ultraviolet absorption measurements of low Z, low density, low temperature plasmas at the Orion Laser Facility Lauren Hobbs, Colin Brown, David Hoarty, Matthew Hill, Steven James, Peter Allan Experiments have been carried out to demonstrate a platform on the Orion laser to study the equation of state of low Z elements in a low density, low temperature regime (around mg/cc, 10s eV). In this regime equation of state models based on Thomas-Fermi ion cell predict significant departure from ideal-gas $+$ ionization predictions. In these experiments absorption measurements using point-projection backlighting aim to determine the change in ionisation as a function of material density at constant temperature to test model prediction. Initial work reported has shown that absorption data can be taken from X-ray heated samples with sufficient accuracy; short-pulse, high-contrast pulses can be used to explode the sample foil to the required low density, and a new XUV grating spectrometer has been commissioned and used for absorption measurements. [Preview Abstract] |
Monday, November 16, 2015 2:12PM - 2:24PM |
CO4.00002: Probing the Release of Shocked Material D.N. Polsin, T.R. Boehly, S. Ivancic, M.C. Gregor, C.A. McCoy, D.D. Meyerhofer, D.E. Fratanduono, P.M. Celliers The behavior of shocked material as it releases to lower pressures is important for equation-of-state experiments and inertial confinement fusion research. We present results of experiments that used a 10-ps, 263-nm probe beam to image the release plumes of various target material shocked to multi-megabar pressures by the OMEGA~EP laser. One-dimensional streaked x-ray radiography also provided a time-resolved trajectory of the release wave. Simultaneous VISAR (velocity interferometer system for any reflector) measurements provide the initial shocked state from which these materials release. Models for the optical properties of the released material is presented. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944. [Preview Abstract] |
Monday, November 16, 2015 2:24PM - 2:36PM |
CO4.00003: Probing Hotspot Conditions in Spherically Shock Compressed Matter Benjamin Bachmann, J. Nilsen, A. L. Kritcher, D. Swift, J. R. Rygg, G. W. Collins, L. Divol, R. W. Falcone, J. Gaffney, S. H. Glenzer, R. Hatarik, J. Hawreliak, S. Khan, D. Kraus, O. L. Landen, N. Masters, S. R. Nagel, T. Pardini, G. Zimmerman, T. Doeppner We present results of an approach to experimentally determine the conditions in the center of a CD$_{\mathrm{2}}$ sphere that has been compressed to petapascal pressures by spherically converging shocks. By measuring the hotspot size using penumbral imaging [1], hotspot temperature using two-color spectroscopy [2], the neutron yield from DD nuclear reactions and the x-ray burn width, we infer average hotspot densities of 43 g/cm$^{\mathrm{3}}$ at 1.6 keV temperature. These conditions correspond to pressures of 4.4 petapascal (44 Gbar) in an ideal gas and 3.5 petapascal from independently performed rad.-hydro. simulations. The experimentally determined neutron yield, temperature and density constrain the EOS in a regime that exceeds previously reported pressures obtained in carbon EOS measurements by three orders of magnitude [3]. The results show a path for constraining the EOS of matter at conditions that have been inaccessible with state-of-the-art experimental EOS techniques. [1] B. Bachmann \textit{et al.}, Rev. Sci. Instrum. 85, 11D606 (2014) [2] B. Bachmann \textit{et al}., J. Phys. D: Appl. Phys. 46, 125203 (2013) [3] R. F. Smith \textit{et al.}, Nature 511, 330-333 (2014) [Preview Abstract] |
Monday, November 16, 2015 2:36PM - 2:48PM |
CO4.00004: Shock compression of glow discharge polymer (GDP): density functional theory (DFT) simulations and experiments on Sandia's Z-machine Thomas R. Mattsson, K.R. Cochrane, T. Ao, R.W. Lemke, D.G. Flicker, M.E. Schoff, B.E. Blue, S. Hamel, M.C. Herrmann Glow discharge polymer (GDP) is used extensively as capsule/ablation material in inertial confinement fusion (ICF) capsules. Accurate knowledge of the equation of state (EOS) under shock and release is particularly important for high-fidelity design, analysis, and optimization of ICF experiments since the capsule material is subject to several converging shocks as well as release towards the cryogenic fuel. We performed Density Functional Theory (DFT) based quantum molecular dynamics (QMD) simulations, to gain knowledge of the behavior of GDP - including the effect of changes in chemical composition. The shock pressures calculated from DFT are compared experimental data taken on magnetically launched flyer plate impact experiments on at Sandia's Z-machine. Large GDP samples were grown in a planar geometry to improve the sample quality and maintained in a nitrogen atmosphere following manufacturing, thus allowing for a direct comparison to the DFT/QMD simulations. Sandia National Laboratories is a multi program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's NNSA under contract DE-AC04-94AL85000. [Preview Abstract] |
Monday, November 16, 2015 2:48PM - 3:00PM |
CO4.00005: High precision Hugoniot measurements of D2 near maximum compression John Benage, Marcus Knudson, Michael Desjarlais The Hugoniot response of liquid deuterium has been widely studied due to its general importance and to the significant discrepancy in the inferred shock response obtained from early experiments. With improvements in dynamic compression platforms and experimental standards these results have converged and show general agreement with several equation of state (EOS) models, including quantum molecular dynamics (QMD) calculations within the Generalized Gradient Approximation (GGA). This approach to modeling the EOS has also proven quite successful for other materials and is rapidly becoming a standard approach. However, small differences remain among predictions obtained using different local and semi-local density functionals; these small differences show up in the deuterium Hugoniot at $\sim$ 30-40 GPa near the region of maximum compression. Here we present experimental results focusing on that region of the Hugoniot and take advantage of advancements in the platform and standards, resulting in data with significantly higher precision than that obtained in previous studies. These new data may prove to distinguish between the subtle differences predicted by the various density functionals. Results of these experiments will be presented along with comparison to various QMD calculations. [Preview Abstract] |
Monday, November 16, 2015 3:00PM - 3:12PM |
CO4.00006: Dynamic Ultra-Bright X-ray Laser Scattering from Isochorically Heated Cryogenic Hydrogen Luke Fletcher Recent x-ray scattering experiments performed at the MEC end-station of the LCLS, have demonstrated novel plasma measurements of the electron temperature, pressure, and density by simultaneous high-resolution angularly and spectrally resolved x-ray scattering from shock-compressed materials in the warm dense regime. Such measurements provide the structural properties relating the microscopic quantities in terms of thermodynamic properties using first-principles calculations. These studies have led us on a path where we create conditions with increasing temperatures and pressures to explore the high-energy density phase space. Specifically, we have begun experiments on hot and dense hydrogen plasmas producing energetic proton beams that find applications in fusion research and astrophysical phenomena. For our experiments with the 25 TW short pulse laser we apply repetition rates and pulse widths with a good match to the LCLS x-ray beam capabilities allowing pump-probe experiments with ultrahigh temporal resolution with very high data throughput with shot rates of up to 5 Hz. In this talk we will discuss our recent measurements that have resolved the ultrafast structural response of hydrogen to intense heating. [Preview Abstract] |
Monday, November 16, 2015 3:12PM - 3:24PM |
CO4.00007: Magnetic Compression of Low Adiabat Liquid Deuterium Filled Cylindrical Liners to Gbar Pressures* Matthew Martin, Patrick Knapp, Daniel Dolan We report on experiments where cylindrical beryllium liners filled with liquid deuterium were compressed to extreme pressure and density with current pulse shaping. ALEGRA MHD simulation, in conjunction with the BERTHA transmission line model of Z accelerator, was utilized to design a shaped current pulse that minimized both the stagnation adiabat of the liquid deuterium and the confining beryllium shell. In one set of experiments the pressure at stagnation is inferred to be $\sim$ 100 Mbar using penetrating radiography. A peak liner convergence ratio (initial radius over final radius) of 7.6 was measured resulting in an average deuterium density of 10 g/cm$^3$ and areal density of 0.45 g/cm$^2$. The stagnation shock propagating radially outward through the liner wall was directly measured with a strength of $\sim$ 120 Mbar. In a second set of experiments the liner was imploded to a peak convergence of 19 resulting in a density of 55 g/cm$^3$ and areal density of 0.5 g/cm$^2$. The pressure at stagnation in this experiment is estimated to be $\sim$ 2 Gbar. This platform enables the study of high-pressure, high-density, implosion deceleration, and stagnation dynamics at spatial scales that are readily diagnosable (radius $\sim$ 0.1mm - 0.4mm). \\[4pt] *Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. [Preview Abstract] |
Monday, November 16, 2015 3:24PM - 3:36PM |
CO4.00008: Equation-of-State Measurements of Resorcinol Formaldehyde Foam Using Imaging X-Ray Thomson Spectrometer Patrick Belancourt, W. Theobald, P.A. Keiter, T.J.B. Collins, M.J. Bonino, P. Kozlowski, R.P. Drake Understanding the equation of state of materials under shocked conditions is important for laboratory astrophysics and high-energy-density physics experiments. This talk will focus on experiments dedicated to developing a platform for measuring the equation of state of shocked foams on OMEGA EP. The foam used in the development of this platform is resorcinol formaldehyde foam with an initial density of 0.34 g/cc. One OMEGA EP beam drives a shock into the foam, while the remaining three beams irradiate a nickel foil to create the x-ray backlighter. The primary diagnostic for this platform, the imaging x-ray Thomson spectrometer (IXTS), spectrally resolves the scattered x-ray beam while imaging in one spatial dimension. The IXTS is ideally suited to measure plasma conditions upstream, downstream and at the shock front in the foam. Preliminary results from these experiments will be shown. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944, the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas DE-NA0001840, and by the National Laser User Facility Program DE-NA0000850. [Preview Abstract] |
Monday, November 16, 2015 3:36PM - 3:48PM |
CO4.00009: Measurements of elastic and plastic waves in polycrystalline diamond under shock compression Michael MacDonald, Luke Fletcher, Jan Vorberger, Maxence Gauthier, Eliseo Gamboa, Alessandra Ravasio, Hae Ja Lee, Eric Galtier, Zhijiang Chen, Dominik Kraus, Ben Barbrel, R Paul Drake, Siegfried Glenzer Direct measurements of the crystal structure of materials under dynamic compression can be obtained using angularly resolved x-ray scattering at the MEC end station of the LCLS facility. In this experiment the 40 fs LCLS x-ray beam enabled time resolved measurements of elastic and plastic waves in polycrystalline diamond, the behavior of which are important to understand for the early stages of compression in inertial confinement fusion targets and planetary interiors. In this experiment two 527 nm optical lasers focused to $4 \times 10^{14}$ W/cm${}^2$ were used to compress 20 and 40 $\mu$m polycrystalline diamond foils. Compression and lattice deformation measurements were made directly from angularly resolved x-ray scattering and compared to DFT simulations. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. 2013155705, DOE Office of Science, Fusion Energy Science under FWP 100182, by DOE/NNSA under grant number DE-NA0001840, and was performed at the MEC instrument of LCLS under contract No. SF00515. The target work was supported by a Laboratory Directed Research and Development grant. [Preview Abstract] |
Monday, November 16, 2015 3:48PM - 4:00PM |
CO4.00010: The Release Behavior of Diamond Shocked to 20 Mbar M.C. Gregor, C.A. McCoy, D.N. Polsin, T.R. Boehly, D.D. Meyerhofer, D.E. Fratanduono, P.M. Celliers, G.W. Collins High-density carbon (HDC) is used as an ablator for inertial confinement fusion experiments at the National Ignition Facility (NIF). Both its Hugoniot and release behaviors are needed for ignition target designs. The OMEGA laser was used to shock HDC to 10 to 20 Mbar; it was then released into materials with known Hugoniots (quartz, CH, silica foam, and liquid deuterium). The impedance-matching technique with these references provides data that constrains the HDC release models. This technique was applied to both the single-crystal diamond and the NIF ablator---ultra-nanocrystalline diamond (UNCD). This study provided the first data for the UNCD Hugoniot and models for the release isentropes of both types of HDC using a Mie--Gr\"{u}neisen equation of state. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944. [Preview Abstract] |
Monday, November 16, 2015 4:00PM - 4:12PM |
CO4.00011: Measurements of Sound Velocity and Gr\"{u}neisen Parameter in CH and MgO Shocked to Mbar Pressures C.A. McCoy, M.C. Gregor, D.N. Polsin, T.R. Boehly, D.D. Meyerhofer, D.E. Fratanduono, P.M. Celliers We present sound velocity measurements using an unsteady wave analysis to relate acoustic perturbations in a sample to those in a standard with known sound velocity and Gr\"{u}neisen parameter. The contraction and dilation of perturbations in the shock velocities in each material provide information on the sound velocity. Experiments measured the sound velocity and Gr\"{u}neisen parameter in shocked CH and MgO (periclase) relative to a quartz standard. Hugoniot measurements were also made for MgO shocked to the fluid state; a modified $U_{\mbox{s}} -u_{\mbox{p}} $ relation is presented. The results are compared to \textit{SESAME} and LEOS tables for CH and MgO. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944. [Preview Abstract] |
Monday, November 16, 2015 4:12PM - 4:24PM |
CO4.00012: Dynamic Shock Compression of Copper to Multi-Megabar Pressure T.A. Haill, M.D. Furnish, L.L. Twyeffort, C.L. Arrington, R.W. Lemke, M.D. Knudson, J.-P. Davis Copper is an important material for a variety of shock and high energy density applications and experiments. Copper is used as a standard reference material to determine the EOS properties of other materials. The high conductivity of copper makes it useful as an MHD driver layer in high current dynamic materials experiments on Sandia National Laboratories Z machine. Composite aluminum/copper flyer plates increase the dwell time in plate impact experiments by taking advantage of the slower wave speeds in copper. This presentation reports on recent efforts to reinstate a composite Al/Cu flyer capability on Z and to extend the range of equation-of-state shock compression data through the use of hyper-velocity composite flyers and symmetric planar impact with copper targets. We will present results from multi-dimensional ALEGRA MHD simulations, as well as experimental designs and methods of composite flyer fabrication. [Preview Abstract] |
Monday, November 16, 2015 4:24PM - 4:36PM |
CO4.00013: Shock wave equation of state experiments at multi-TPa pressures on NIF P.M. Celliers, D.E. Fratanduono, J.L. Peterson, N.B. Meezan, A.J. MacKinnon, D.G. Braun, M. Millot, J. Fry, K.J. Boehm, P.A. Sterne, G.W. Collins, A. Nikroo, P. Fitzsimmons The National Ignition Facility provides an unprecedented capability to generate steady, planar, ultra-high pressure shock waves (up to 10 TPa or more) in solid samples. Building on successful laser shock equation of state experiments performed on a variety of other laser facilities, we have designed and fielded experiments to perform impedance match experiments on samples of C, Be, SiO$_2$ and CH, in the range of 3 to 7 TPa. The experiments use a line-imaging VISAR as the primary diagnostic to measure the shock velocity in an Al reference standard and in an array of the four samples. Initial tests with the line-imaging VISAR show that the NIF is capable of driving shocks that are steady to better than 2\% in velocity for several ns, with smooth planar breakout patterns over a 2 mm diameter spot. Hugoniot data points will be compared to current equation-of-state models for the various materials under study. [Preview Abstract] |
Monday, November 16, 2015 4:36PM - 4:48PM |
CO4.00014: Hugoniot measurements at near Gbar pressures at the NIF Andrea Kritcher, Damian Swift, Tilo Doeppner, Gilbert Collins, Benjamin Bachmann, Joe Nilsen, Dave Chapman, Alfredo Correa, Phil Sterne, Lorin Benedict, Jim Gaffney, Dominik Kraus, Roger Falcone, Siegfried Glenzer, Steve Rothman Laboratory measurements of the Equation of State (EOS) of matter at high pressure are of great importance in the understanding and accurate modeling of matter at extreme conditions. For example, at hundreds of Mbars - Gbar pressures atomic shell effects may come into play, which can change the predicted compressibility at given pressure due to pressure and temperature ionization. In this work we present measurements of the strong shock hugoniot, at pressures up to 720 Mbar for CH and 630 Mbar for High Density Carbon (HDC, or diamond) at the National Ignition Facility (NIF). Spherically convergent shocks are launched into solid CH or diamond samples, using a hohlraum radiation drive. X-ray radiography is applied to measure the shock speed and infer the mass density profile, enabling determining of the shock pressure and Hugoniot equation of state. *This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48. Supported by LDRD 08-ERI-003. [Preview Abstract] |
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