Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session Y38: Materials in Extremes: Warm Dense MatterFocus

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Sponsoring Units: DCOMP GSCCM DMP Chair: Lorin Benedict, Lawrence Livermore National Laboratory Room: LACC 501A 
Friday, March 9, 2018 11:15AM  11:51AM 
Y38.00001: MaRIE: MatterRadiation Interactions in Extremes Capability and Fulfilling the Requirements of Future MultiScale Materials Modeling Invited Speaker: Cris Barnes , Curt Bronkhorst , Edward Kober , Richard Sheffield , Jack Shlachter DOE and NNSA have a mission need for flexible, reducedcost productbased solutions to materials through accelerated qualification, certification, and assessment. Development and especially lifecycle certification of such solutions requires predictive capability of material’s production and performance. The science challenge lies between the nanoscale and the integral device scale, at the middle or "mesoscale" where interfaces, defects, and microstructure determine the performance. What is the future of multiscale materials modeling, enabled by exascale and beyond computing, and how do we challenge that modeling to ensure it is effective? Experimental data of high fidelity and resolution in both time and space are necessary to discover the right mechanisms to model, validate and calibrate models in codes. Achieving this capability requires taking advantage of the ongoing revolution in coherent imaging of nonperiodic features and using scattering off periodic structures. These imaging techniques require a coherent xray source, brilliant and high repetition rate, with high energy to see into and through the mesoscale. The MatterRadiation Interactions in Extremes (MaRIE) Project is intended to deliver such capability through a veryhighenergy Xray free electron laser. 
Friday, March 9, 2018 11:51AM  12:03PM 
Y38.00002: Interfacial Mixing in Warm Dense Matter with a Multiphysics Kinetic Model Jeff Haack , Michael Murillo , Cory Hauck We have extended a recently developed multispecies, multitemperature BGK model [Haack et al., J. Stat. Phys., 168, (2017)] to include multiphysics capabilities that enable modeling of a wider range of physical conditions. We have included an atomic ionization model, accurate collision physics across coupling regimes, selfconsistent electric fields, and degeneracy in the electronic screening. We apply the model to a warm dense matter scenario in which the ablatorfuel interface of an inertial confinement fusion target is heated, similar to the recent molecular dynamics study in [Stanton et al., submitted to PRX], but for larger length and time scales and for much higher temperatures. We observe hydrogen from the ablator material jetting into the fuel during the early stages of the implosion and compare the relative size of various diffusion components that drive this process. We also examine kinetic effects, such as anisotropic distributions and velocity separation, in order to determine when this problem can be described with a hydrodynamic model. 
Friday, March 9, 2018 12:03PM  12:15PM 
Y38.00003: Copper Hugoniot and Release Measurements to 2.6 TPa on Z Michael Furnish , Thomas Haill We conducted three Hugoniot and release experiments on copper on the Z machine at Hugoniot stress levels of 0.34 and 2.6 TPa, using twolayer copper/aluminum impactors traveling at 8 and 27 km/s and Zquartz windows. Velocity histories were recorded for 4 samples of different thicknesses and 5 locations on the flyer plate (3 and 4 for the first two experiments). Onsample measurements provided Hugoniot points (via transit time) and partial release states (via Zquartz wavespeed). Fabrication of the impactor required thick plating and several diamondmachining steps. The lowerpressure test was planned as a 2.5 TPa test, but a failure on the Z machine degraded its performance; however, these results corroborated earlier Cu data in the same stress region. The second test suffered from significant flyer plate bowing, but the third did not. The Hugoniot data are compared with the Al'tshuler/Nellis nucleardriven data, other data from Z and elsewhere, and representative Sesame models. 
Friday, March 9, 2018 12:15PM  12:27PM 
Y38.00004: XRay absorption spectra of two temperatures warm dense copper Vanina Recoules , Noemie Jourdain , Ludovic Lecherbourg , Patrick Renaudin , Fabien Dorchies The time evolution of X Ray absorption spectra near L_{2,3} edge is measured in copper heated up to the warm dense matter regime by a femtosecond laser pulse. Measurement was performed using Eclipse laser and a tabletop station dedicated to Time Resolved XANES measurement at CELIA laboratory. The recorded spectra are successfully compared with spectra computed using ab initio quantum molecular dynamic calculations with ABINIT code. By a strong interplay between theory and experiment, we demonstrate that the observed preedge in the L_{3}edge reveals the time evolution of the electron temperature before equilibration. The modulation behind the edge are a signature of the ionic order as the copper goes from the solid to liquid. 
Friday, March 9, 2018 12:27PM  12:39PM 
Y38.00005: Stopping Power of Warm Dense Matter from TDDFTEhrenfest Molecular Dynamics Attila Cangi , Daniel Jensen , Andrew Baczewski Recent experimental advances enabled the precise measurement of the stopping power of fusion products in warm dense matter. We assess the ability of realtime timedependent density functional theory to reproduce these results. Our approach facilitates the prediction of the stopping power in future experiments from first principles and advances our empirical and phenomenological understanding of transport properties in this technologically challenging thermodynamic regime. 
Friday, March 9, 2018 12:39PM  12:51PM 
Y38.00006: Computing Optical Conductivities of Warm Dense Matter with TimeDependent Density Functional Theory Daniel Jensen , Andrew Baczewski , Attila Cangi , Stephanie Hansen In magnetized liner inertial fusion (MagLIF), matter is subjected to 1030 T magnetic fields that are then flux compressed to strengths greater than 1 kT [Slutz et al, Phys. Rev. Lett. 108, 025003 (2012)]. The determination of optical and transport properties for warm dense matter in such extreme fields is of vital importance to experimental design. We show how timedependent density functional theory can be used to extract optical conductivities in and beyond the linear response regime. Building on work studying scalar linear perturbations to warm dense matter [Baczewski et al., Phys. Rev. Lett. 116, 115004 (2016)], we present the necessary theoretical modifications as well as some preliminary results. 
Friday, March 9, 2018 12:51PM  1:03PM 
Y38.00007: Electronion spatiotemporal relaxation behavior of laser heated iron nanofoil studied by time resolved XANES and abinitio simulations Amalia fernandez , Tadashi Ogitsu , Alfredo Correa , Sebastien Hamel , Kyle Engelhorn , Ben Barbrel , David Prendergast , Sri Chaitanya Das Pemmaraju , Philip Heimann , Roger Falcone , Jon Eggert , Yuan Ping Thermophysical properties such as specific heat, electronphonon coupling, thermal conductivity under electronion nonequilibrium condition in warm dense matter regime (T ~ a few eV) are largely unknown mainly because of the lack of wellestablished experimental methods. In recent years, significant progresses have been made in both theoretical and experimental techniques that allow us to access to such information. In this presentation, we will discuss an experiment using time resolved XANES that allows us to extract sufficient information for constraining the thermophysical properties of our interest, where abinitio derived twotemperature model is used to simulate the spatiotemporal electronion relaxation behavior of nanometer thin iron foil that is exposed to femto second laser pulse, which in turn is used to simulate temporal behavior of XANES spectrum. Importance of the choices of geometrical design of target as well as corresponding laser fluece will also be discussed in detail. 
Friday, March 9, 2018 1:03PM  1:15PM 
Y38.00008: Transport properties of binary and ternary assymetric warm dense plasma mixtures modeled by orbitalfree DFT molecular dynamic Alexander White , Lee Collins , Joel Kress , Christopher Ticknor , Jean Clerouin , Philippe Arnault , Nicolas Desbiens We calculate concentration dependent transport properties of assymetric warm dense plasma mixtures at pressuretemperature equilibrium. Orbitalfree density functional theory based molecular dynamics (OFMD) simulations are used to accurately determine these transport properties from first principles. We compare our results to a more approximate pseudoion in jellium model. Results demonstrate that small concentrations of heavy elements have a drastic effect on light element transport. Crossover behavior from kinetic to correlated regimes is also shown. Hydrogen overcorrelation, due to the heavy element, translates into a strong enhancement of nuclear reactions which is evidenced by the calculation of the H factor using the Widom expansion. Additionally, results from simulations of ternary mixtures will be presented. 
Friday, March 9, 2018 1:15PM  1:27PM 
Y38.00009: A viscous quantum hydrodynamics model based on dynamic density functional theory Abdourahmane Diaw Dynamic density functional theory (DDFT) is emerging as a useful theoretical technique for modeling the dynamics of correlated systems. We extend DDFT to quantum systems for application to dense plasmas through a quantum hydrodynamics (QHD) approach. The DDFTbased QHD approach includes correlations in the the equation of state selfconsistently, satisfies sum rules and includes irreversibility arising from collisions. While QHD can be used generally to model nonequilibrium, heterogeneous plasmas, we employ the DDFTQHD framework to generate a model for the electronic dynamic structure factor, which offers an avenue for measuring hydrodynamic properties, such as transport coefficients via xray Thomson scattering. 
Friday, March 9, 2018 1:27PM  1:39PM 
Y38.00010: Reflectivity evolution of quasiequilibrium warm dense gold heated by the Lband X ray from the hohlraum Dongxiao Liu , Yuqiu Gu The evolution of reflectivity for quasiequilibrium warm dense gold in the metalnonmetal transition regime has been investigated by combining the experimental measurement and ab initio simulations. The expanded gold fluid is generated by the heating of the hard Xray (Lband) from the hohlraum. The reflectivity and expanding velocity of interface are diagnosed by the VISAR. The Lband fraction is adjusted in 1D radiation hydrodynamic simulations by Multi1D to match the expanding velocity of experimental measurement using MPQEOS and multi group Thermos opacity. Ab initio calculations have been performed based on the temperature and density points extracted from the Multi1D simulation. The evolution of reflectivity between the experimental measurement and the ab initio simulations has been compared. The reflectivity from simulations is lower than the experimental data. The probable reason for this difference is from energy shift due to the GGA exchange correlation functional used in the reflectivity calculations. 
Friday, March 9, 2018 1:39PM  1:51PM 
Y38.00011: FirstPrinciples Calculations of Xray Thomson Scattering Spectrum of Warm Dense Matter Chongjie Mo , Zhenguo Fu , Wei Kang , Ping Zhang , X.T. He Through the perturbation formula of timedependent density functional theory (TDDFT) broadly employed in the calculation of solids, we provide a firstprinciples calculation of the electronic dynamic structure factor in warm dense region. 
Friday, March 9, 2018 1:51PM  2:03PM 
Y38.00012: Prediction of a new class of group 14 inclusion compounds encapsulating noble gases Enshi Xu , Hanyu Liu , Yuanfei Bi , Timothy Strobel , Tianshu Li Group 14 elements (Si, Ge, Sn) exhibit a complex potential energy landscape and thus a vast array of allotropes emerge under extreme conditions. Employing density functional theory and molecular dynamics (MD) simulations, we predicted a new class of inclusiontype compounds of group 14 elements as host and noble gases (NG) as guest. The new compounds are structural analogs to the highpressure phases of methane hydrate, a.k.a. “filled ices”. The stability of the compounds quickly increases with both the size of host and guesthost interaction. In particular, some SnNG systems are predicted to be thermodynamically stable. Our MD simulations show the crystallization of these compounds is kinetically favorable from the liquid of host in the presence of NG, as NG is found to induce a local ordering of liquid that structurally matches the compounds. To strengthen our conclusion, we have also employed highlevel quantum chemistry calculations to examine the fundamental guesthost interaction, which allows further validating our predictions. Our study thus suggests a viable experimental route for synthesis under high pressure and high temperature. Experimental validation of our prediction is currently being carried out. 
Friday, March 9, 2018 2:03PM  2:15PM 
Y38.00013: Nonempirical Semilocal FreeEnergy Density Functional for Warm Dense Matter Valentin Karasiev , James Dufty , Sam Trickey Realizing the potential for predictive density functional calculations of warm dense matter 
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