Bulletin of the American Physical Society
58th Annual Meeting of the APS Division of Plasma Physics
Volume 61, Number 18
Monday–Friday, October 31–November 4 2016; San Jose, California
Session BO4: Equation of State & X-ray Radiation |
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Chair: Guillaume Loisel, Sandia National Laboratories Room: 230 A |
Monday, October 31, 2016 9:30AM - 9:42AM |
BO4.00001: Developing absolute shock wave equation of state measurements on the NIF Peter Celliers, D. E. Fratanduono, A. Lazicki, R. A. London, S. Brygoo, D. C. Swift, F. Coppari, M. Millot, J. L. Peterson, N. B. Meezan, A. Fernandez-Panella, D. J. Erskine, S. Ali, G. W. Collins The National Ignition Facility provides an unprecedented capability to generate ultra-high pressure planar shock waves (around 10 TPa) in solid samples. We are currently fielding impedance match equation of state (EOS) experiments to determine the shock Hugoniot of various samples relative to EOS standards, such as aluminum and quartz. However, the equations of state of the standards at multi-TPa shock pressures are not yet well-established. Absolute techniques are needed to provide the data needed to establish the Hugoniots of the standards, and also to measure the state of a sample directly. We are pursuing several approaches using absolute techniques. These approaches will be discussed. [Preview Abstract] |
Monday, October 31, 2016 9:42AM - 9:54AM |
BO4.00002: Shock compression of D2 to 500 GPa along the principal Hugoniot A. Fernandez-PaƱella, D. Fratanduono, M. Millot, G. W. Collins, P. Celliers, M. Gregor, T. R. Boehly Impedance-match measurements along the principal Hugoniot of deuterium using an Al standard were carried out about 10 years ago at the OMEGA and the Z facilities. The data at the highest pressures (near 200 GPa) suggest a systematically softer response than current equation of state (EOS) models, although the measurement uncertainties are too large to confirm a disagreement with the models. More recent data sets from shock timing experiments on the National Ignition Facility for the inertial confinement fusion program, and a reanalysis of old OMEGA data to extract the sound speed suggest that the deuterium Hugoniot may indeed be softer than the models predict above 150 GPa. We have investigated this issue with recent experiments at the OMEGA laser facility, and we present new impedance-match data along the deuterium principal Hugoniot in the 250-500 GPa range obtained with higher measurement accuracy using quartz as the impedance match standard. This work was performed under the auspices of the U.S. Department of Energy by LLNL under contract DE-AC52-07NA27344. [Preview Abstract] |
Monday, October 31, 2016 9:54AM - 10:06AM |
BO4.00003: Observation of Solid--Solid Phase Transitions in Ramp-Compressed Aluminum D.N. Polsin, T.R. Boehly, J.A. Delettrez, M.C. Gregor, C.A. McCoy, B. Henderson, D.E. Fratanduono, R. Smith, R. Kraus, J.H. Eggert, R. Collins, F. Coppari, P.M. Celliers We present results of experiments using x-ray diffraction to study the crystalline structure of solid aluminum compressed up to 500 GPa. Aluminum is of interest because it is frequently used as a standard material in high-pressure compression experiments. At ambient pressure and temperature, Al is a face-centered cubic close-packed crystal and has been observed to transform to hexagonal close-packed (hcp) when compressed to $\sim 200\mbox{\thinspace GPa}$ in a diamond anvil cell. It is predicted to transform from hcp to body-centered cubic when compressed to $\sim 315\mbox{\thinspace GPa.}$ Laser-driven ramp waves will be used to compress Al to various constant-pressure states. The goal is to investigate the Al phase diagram along its isentrope, i.e., at temperatures $\sim 1000\mbox{\thinspace K}$ and pressures ranging from 200 to 500 GPa. X-ray diffraction will be used to measure the crystalline structure of the compressed Al and observe the transformations that occur at various pressures. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944. [Preview Abstract] |
Monday, October 31, 2016 10:06AM - 10:18AM |
BO4.00004: Design and analysis of x-ray driven shock wave equation-of-state experiments on the National Ignition Facility R. A. London, A. Lazicki, P. M. Celliers, D. J. Erskine, D. E. Fratanduono, N. B. Meezan, J. L. Peterson The equation-of-state (EOS) is important for describing and predicting material properties in the field of high energy density physics. Especially important is the EOS of materials compressed and heated from ambient conditions by shockwaves. For most materials, experimental data at high pressures, much above 10 Mbar, is sparse. The large energy and power of the National Ignition Facility readily enable EOS experiments in a new regime, at pressures on order of 100 Mbar. We describe a platform for EOS measurements using planar shockwaves driven by x rays within a hohlraum target. The EOS is determined by an impedance matching method, using a reference material of known EOS. For transparent materials, the shock velocity is measured directly by optical interferometry, while for opaque materials, the measurement is done by timing the entrance and exit of the shock and correcting for time variations with an adjacent transparent reference. We describe the computational design and analysis of experiments. Predicted shock velocities and transit times are used to set the target layer thicknesses and interferometer timing. Data from several NIF shots are compared to post-shot calculations. New, high pressure EOS data is presented for several materials. [Preview Abstract] |
Monday, October 31, 2016 10:18AM - 10:30AM |
BO4.00005: X-ray diffraction measurements of polycrystalline diamond near the Hugoniot elastic limit under shock compression M. J. MacDonald, E. E. McBride, P. Sun, M. Gauthier, E. J. Gamboa, D. Kraus, W. Schumaker, J. Vorberger, E. Galtier, T. B. van Driel, X. Zhou, E. Granados, I. Nam, R. P. Drake, S. H. Glenzer, L. B. Fletcher Direct measurements of the crystal structure under dynamic compression can be made using angularly resolved x-ray scattering at the MEC instrument at LCLS. Diffraction from several lattice planes using the x-ray beam at LCLS enabled time resolved measurements of elastic and plastic waves in polycrystalline diamond near the Hugoniot elastic limit. The behavior of diamond in these conditions is important to the understanding of the early stages of compression in inertial confinement fusion targets, meteorite impact events, and planetary interiors. Data were analyzed in the Reuss limit as described in a recent publication [M. J. MacDonald et al., J. Appl. Phys. 119, 215902 (2016)] to model the stresses near the Hugoniot elastic limit. This material is based upon work supported by the NSF under Grant No. 2013155705. This work was supported by the DOE Office of Science, FES under FWP 100182, by the NNSA-DS and SC-OFES Joint Program in HED Laboratory Plasmas, Grant No. DE-NA0002956, and used resources of the NERSC under Contract No. DE-AC02-05CH11231. [Preview Abstract] |
Monday, October 31, 2016 10:30AM - 10:42AM |
BO4.00006: Dissociation along the principal Hugoniot of plastic ablator materials Gael Huser, Pierre Colin-Lalu, Vanina Recoules, Gwenael Salin, Norimasa Ozaki, Kohei Miyanishi, Takayoshi Sano, Yuuichi Sakawa, Erik Brambrink, Tommaso Vinci, Bolis Riccardo Plastic materials are used as ablators in Inertial Confinement Fusion capsules for the National Ignition Facility and Laser M\'{e}gajoule. First-principles ab initio simulations of Glow discharge polymer hydrocarbon (GDP-CH) as well as Si-doped GDP-CH principal Hugoniot curves up to 8 Mbar were performed using the quantum molecular dynamics (QMD) code Abinit and showed that atomic bond dissociation increases the compressibility, which is not taken into account by average-atom models. Results from these simulations are used to parameterize a quantum semi-empirical model in order to generate a tabulated Equation of State (EOS) that includes dissociation. Hugoniot measurements obtained from experiments conducted at LULI2000 and GEKKOXII laser facilities confirm QMD simulations as well as EOS modeling. Our model also applies to reanalyzed data of other plastic materials and its influence on shock timing is evaluated using hydrodynamic simulation. [Preview Abstract] |
Monday, October 31, 2016 10:42AM - 10:54AM |
BO4.00007: Hugoniot Measurements of Silicon Shock Compressed to 25 Mbar B. Henderson, D.N. Polsin, T.R. Boehly, M.C. Gregor, S.X. Hu, G.W. Collins, J.R. Rygg, D.E. Fratanduono, P.M. Celliers We present results of laser-driven shock experiments that compressed silicon samples to 25 Mbar. Impedance matching to a quartz reference provided Hugoniot data. Since silicon is opaque, a quartz witness was placed adjacent to the silicon samples; this afforded the use of the unsteady wave correction\footnote{ D. E. Fratanduono \textit{et al}., J. Appl. Phys. \textbf{116}, 033517 (2014).\par \par } to increase the precision of the transit-time measurements of shock velocity. Results are compared both \textit{SESAME} tables and to quantum molecular dynamics calculations. This material is based upon work supported by the Department Of Energy National Nuclear Security Administration under Award Number DE{\-}NA0001944. [Preview Abstract] |
Monday, October 31, 2016 10:54AM - 11:06AM |
BO4.00008: Transverse Diffraction at the LCLS: Shock-Compressed Silicon E. E. McBride, A. Krygier, M.. Harmand, Z.. Konopkova, H.-P. Liermann, A. Schropp, S. Toleikis, A. Pelka, M. Roedel, C. Spindloe, R. F. Smith, E. Galtier, H. J. Lee, B. Nagler, Th. Tschentscher, J. S. Wark, A. Higginbotham Despite being the subject of numerous shock compression studies, the behavior of silicon under dynamic loading is vigorously debated [1-4]. The few studies that combine shock compression and X-ray diffraction have exclusively focused on ``normal'' X-ray geometry whereby X-rays are collected along the shock propagation direction, consequently sampling numerous strain states at once, greatly complicating both phase identification and studies of phase transition kinetics. Here, we present a novel setup performing in situ X-ray diffraction studies perpendicular to the shock propagation direction at the Matter at Extreme Conditions end station at LCLS. Combining the extremely bright microfocussed X-ray beam with a nanosecond drive laser, we unambiguously determine the character of each wave for the first time. [1] Graham et al., JPCS, 27, 9 (1966) [2] Turneaure {\&} Gupta, APL, 90, 051905 (2007) [3] Colburn et al., JAP, 43, 5007 (1972) [4] Gust {\&} Royce, JAP, 42, 1897 (1971) [Preview Abstract] |
Monday, October 31, 2016 11:06AM - 11:18AM |
BO4.00009: Measuring Ionization in Highly Compressed, Near-Degenerate Plasmas Tilo Doeppner, D. Kraus, P. Neumayer, B. Bachmann, G.W. Collins, L. Divol, A. Kritcher, O.L. Landen, A. Pak, C. Weber, L. Fletcher, S.H. Glenzer, R.W. Falcone, A. Saunders, D. Chapman, R. Baggott, D.O. Gericke, A. Yi A precise knowledge of ionization at given temperature and density is required to accurately model compressibility and heat capacity of materials at extreme conditions. We use x-ray Thomson scattering to characterize the plasma conditions in plastic and beryllium capsules near stagnation in implosion experiments at the National Ignition Facility. We expect the capsules to be compressed to more than 20x and electron densities approaching 10$^{25}$ cm$^{-3}$, corresponding to a Fermi energy of 170 eV. Zinc He$_{\alpha}$ x-rays (9 keV) scattering at 120$^{\circ}$ off the plasma yields high sensitivity to K-shell ionization, while at the same time constraining density and temperature. We will discuss recent results in the context of ionization potential depression at these extreme conditions. [Preview Abstract] |
Monday, October 31, 2016 11:18AM - 11:30AM |
BO4.00010: A platform for detecting material melting from shock compression using the NIF x-ray diffraction diagnostic TARDIS Christopher Wehrenberg, Richard Kraus, Dave Braun, Ryan Rygg, Federica Coppari, Amy Lazicki, James McNaney, Jon Eggert A series of experiments were performed on NIF to develop a platform to detect material melting during shock compression using x-ray diffraction. The unique pulse shaping on NIF can be utilized to directly-drive a steady shock into an ablator and material sample while simultaneously creating an x-ray source to probe the material state. Sharp diffraction lines are observed when the material is in the solid state, while broad diffuse lines are seen when in the liquid state, providing an unambiguous signal for shock driven melting. Several shots were performed in which a shock of 50-80 GPa was driven into a Pb sample while a Ge foil was used as an x-ray source probe. Laser conditions were varied to create a suitable x-ray source that provides a short, bright burst of He-alpha emission from the Ge while maintaining a low background level on the image plates contained in the TARDIS diagnostic. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344. [Preview Abstract] |
Monday, October 31, 2016 11:30AM - 11:42AM |
BO4.00011: Picosecond Streaked K-Shell Spectroscopy of Near Solid-Density Aluminum Plasmas C.R. Stillman, P.M. Nilson, S.T. Ivancic, C. Mileham, D.H. Froula, I.E. Golovkin The thermal x-ray emission from rapidly heated solid targets containing a buried-aluminum layer was measured. The targets were driven by high-contrast 1$\omega $ or 2$\omega $ laser pulses at focused intensities up to $1\mbox{\thinspace }\times \mbox{\thinspace }10^{19}\mbox{\thinspace }{\mbox{W}} \mathord{\left/ {\vphantom {{\mbox{W}} {\mbox{cm}^{2}}}} \right. \kern-\nulldelimiterspace} {\mbox{cm}^{2}}.$ A streaked x-ray spectrometer recorded the Al He$_{\alpha }$ and lithium-like satellite lines with 2-ps temporal resolution and moderate resolving power $\left( {E \mathord{\left/ {\vphantom {E {\Delta E\approx 700}}} \right. \kern-\nulldelimiterspace} {\Delta E\approx 700}} \right).$ Time-integrated measurements over the same spectral range were used to correct the streaked data for variations in photocathode sensitivity. Line widths and intensity ratios from the streaked data were interpreted using a collisional radiative atomic model to provide the average plasma conditions in the buried layer as a function of time. It was observed that the resonance line tends toward lower photon energies at high electron densities. The measured shifts will be compared to predicted shifts from Stark-operator calculations at the inferred plasma conditions. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944, the office of Fusion Energy Sciences Award Number DE-SC0012317, and the Stewardship Science Graduate Fellowship Grant Number DE-NA0002135. [Preview Abstract] |
Monday, October 31, 2016 11:42AM - 11:54AM |
BO4.00012: Line Emission and X-ray Line Polarization of Multiply Ionized Mo Ions E.E. Petkov, A.S. Safronova, V.L. Kantsyrev, V.V. Shlyaptseva, A. Stafford, U.I. Safronova, I.K. Shrestha, K.A. Schultz, R. Childers, M.C. Cooper, P. Beiersdorfer, N. Hell, G.V. Brown We present a comprehensive experimental and theoretical study of the line emission from multiply ionized Mo ions produced by two different sets of experiments: at LLNL EBIT and the pulsed power generator Zebra at UNR. Mo line emission and polarization measurements were accomplished at EBIT for the first time. In particular, benchmarking experiments at the LLNL EBIT with Mo ions produced at electron beam energies from 2.75 keV up to 15 keV allowed us to break down these very complicated spectra into spectra with only few ionization stages and to select processes that influence them as well as to measure line polarization. The EBIT data were recorded using the EBIT Calorimeter Spectrometer and a crystal spectrometer with a Ge crystal. X-ray Mo spectra and pinhole images were collected from Z-pinch plasmas produced from various wire loads. Non-LTE modeling, high-precision relativistic atomic and polarization data were used to analyze L-shell Mo spectra. The influence of different plasma processes including electron beams on Mo line radiation is summarized. [Preview Abstract] |
Monday, October 31, 2016 11:54AM - 12:06PM |
BO4.00013: X-ray heating of a neon photoionized plasma experiment at Z R Mancini, T Lockard, D Mayes, G Loisel, J Bailey, G Rochau, J Abdallah In experiments performed at the Z facility of Sandia National Laboratories a cm-scale cell filled with neon gas was driven by the burst of broadband x-rays emitted at the collapse of a wire-array z-pinch turning the gas into a photoionized plasma. Transmission spectroscopy of a narrowband portion of the x-ray flux was used to diagnose the plasma. The time-integrated data show a highly-ionized neon plasma with a rich line absorption spectrum that permits the extraction of the ionization distribution. Data analysis produced ground and low excited state areal densities and from the ratio of first-excited to ground state populations in Li-like neon a temperature of 19$\pm$ 4eV was extracted to characterize the x-ray heating of the plasma. To interpret this observation, we have performed modeling calculations of the spectral distribution of the x-ray drive, self-consistent modeling of electron and atomic kinetics, and radiation-hydrodynamic simulations. We found that to compute electron temperatures consistent with observation the details of the photon-energy distribution of the drive, x-ray attenuation through the cell window, and non-equilibrium collisional-radiative neon atomic kinetics need to be taken into account. This work was sponsored by DOE Office of Science Grant DE-SC0014451, and the Z Fundamental Science Program. [Preview Abstract] |
Monday, October 31, 2016 12:06PM - 12:18PM |
BO4.00014: L- and K-shell emission from X-FEL heated iron Philip Heimann, Stephanie Hansen, Guillaume Loisel, James Bailey, Eliseo Gamboa, Siegfried Glenzer, Roberto Mancini, Alison Saunders, Roger Falcone, Eric Galtier At the LCLS MEC instrument, a tightly focused X-ray FEL beam is used to isochorically heat thin iron samples. Two compound refractive lenses produce a focus estimated to be 0.5 microns (FWHM). The L-emission from the hot, solid-density samples is measured by RAP(001) crystal and grating spectrometers. In addition, the K-emission is observed by a Ge(111) crystal spectrometer. The L-shell emission from iron, which is initially photoionized by the X-ray FEL, tests recent measurements indicating higher-than-predicted broadening of the L-shell emission lines. Heating at 7 and 9.2 keV photon energies compares different heating mechanisms. [Preview Abstract] |
Monday, October 31, 2016 12:18PM - 12:30PM |
BO4.00015: Characterization of the ultrafast x-ray heating of iron foils Eliseo Gamboa, Guillaume Loisel, Philip Heimann, James Bailey, Roger Falcone, Eric Galtier, Siegfried Glenzer, Andy MacKinnon, Roberto Mancini, Alison Saunders, Stephanie Hansen We present experimental data showing the thermodynamic response of metal foils to intense x-ray irradiation. Thin (300 nm) iron foils were irradiated with up to 3 mJ of x-rays in a 9 keV, 40 fs free electron laser pulse generated by the Linac Coherent Light Source, Stanford University. The x-rays heat the foil uniformly, depositing several keV/atom to create a hot-dense state. We observed the non-collective x-ray scattering from the laser pulse, obtaining wavelength-resolved spectra that are sensitive to the temperature and charge distribution in the sample. The values inferred from the x-ray scattering are compared to predictions from atomic kinetics simulations as well as time-integrated measurements of the temperature from the soft x-ray bremsstrahlung emission. [Preview Abstract] |
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