Bulletin of the American Physical Society
63rd Annual Meeting of the APS Division of Plasma Physics
Volume 66, Number 13
Monday–Friday, November 8–12, 2021; Pittsburgh, PA
Session BO05: HED: Warm and Hot Dense MatterOn Demand
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Chair: Adam Sefkow, Rochester University Room: Rooms 306-307 |
Monday, November 8, 2021 9:30AM - 9:42AM |
BO05.00001: A Measurement of the Electron-Ion Equilibration Rate in Warm Dense Gold with High-Resolution Inelastic X-ray Scattering Thomas G White, Eric Galtier, Haeja Lee, Dimitri Khaghani, Sameen Yunus, Eric Cunningham, Jerome B Hastings, Siegfried Glenzer, Emma McBride, Luke Fletcher, Giulio Monaco, Ulf Zastrau, Karen Appel, Sebastian Goede, Lennart Wollenweber, Dirk Gericke, Gianluca Gregori, Bob Nagler When a high-intensity laser is incident on a solid target, the preferential and rapid heating of one subsystem over the other creates a highly non-equilibrium state[1,2]. These transient, high-energy-density plasmas are a precursor to warm dense matter (WDM) and serve as a testbed where we can validate quantum mechanical theories of electron-ion interactions. We have implemented a high-resolution (~50 meV) X-ray scattering platform[3], designed for use with free-electron lasers, with a resolution capable of measuring the quasi-elastic Rayleigh peak. The width of this peak, which is essentially governed by Doppler broadening, provides a direct measurement of the ions velocity distribution and corresponds to a model-independent ion temperature measurement. We have measured the rise of the ion temperature in laser-excited gold films during the first 25 ps after irradiation, during which the ions are rapidly heated to electronvolt temperatures. The extracted electron-ion equilibration rate is compared to several theoretical and computational models. |
Monday, November 8, 2021 9:42AM - 9:54AM |
BO05.00002: Direct imaging of the structural change in strongly excited liquid water Mianzhen Mo, Shujiang Liang, Chaobo Chen, Daniel Deponte, Mikhail Arefev, Christopher Crissman, Chandra Breanne Curry, Zhijiang Chen, Adrien Descamps, Maxence Gauthier, Michael Kozina, Ming-Fu Lin, J. Pedro F. Nunes, Xieyu Na, Benjamin K Ofori-Okai, Das Pemmaraju, Xiaozhe Shen, Jie Yang, Leonid Zhigilei, Xijie Wang, Siegfried Glenzer Understanding the structural properties of liquid water in warm dense conditions has numerous implications for areas including astrophysics, shock physics and solution-phase chemistry. Here we report the results of using femtosecond electron diffraction to directly image the structural change in warm dense water formed by strong optical excitation of liquid water. In this study, a 266 nm, 100 fs laser pulse was focused onto a liquid water sheet of ~650 nm thickness, reaching a maximum excitation energy density of ~5.4 MJ/kg. Structural change of the excited water was probed with time-resolved electron diffraction up to 500 ps after laser arrival. The diffraction data is converted to differential pair distribution function (DPDF) to resolve the dynamics of intermolecular O···O and O···H bonds of water. The DPDF results show that the structural change is dominated by OH(H3O+) radical-cation pairs within 0.5 ps, followed by a steady state up to 50 ps and a transition to phase explosion regime on a 100-ps time scale. |
Monday, November 8, 2021 9:54AM - 10:06AM |
BO05.00003: Developing x-ray Fresnel Diffractive-Refractive Radiography for Measuring Mutual Diffusion in Warm Dense Matter Cameron H Allen, Matthew Oliver, Laurent Divol, Andreas J Kemp, Otto L Landen, Yuan Ping, Markus Schoelmerich, Wolfgang R Theobald, Tilo Doeppner, Thomas G White The experimental measurement of evolving density gradients at the interface of two warm dense matter (WDM) species can inform us about dynamic transport properties and the equation of state. We have developed x-ray Fresnel diffractive-refractive radiography (FDR), which combines an ultra-small source size with an isochorically-heated buried wire sample, to create a high spatial resolution (~1µm) radiography platform for large laser facilities such as Omega and the NIF. The high spatial resolution allows for imaging of refractive and diffractive features at the interface1,2,3, and therefore precise measurement of the evolving interface as the materials expand after heating. We will discuss results from our recent OMEGA experiments using plastic-coated 4µm W wire targets, where we saw significant expansion of the W into plastic, resulting in shock propagation and distinct changes in the refraction/diffraction features at the interface. |
Monday, November 8, 2021 10:06AM - 10:18AM |
BO05.00004: Thermal Transport Study of warm dense CH and Be by Refraction-Enhanced X-ray Radiography with a Deep Neural Network analysis Sheng Jiang, Otto L Landen, Heather D Whitley, Sebastien Hamel, Richard A London, Philip A Sterne, Daniel S Clark, Stephanie B Hansen, Suxing Hu, Gilbert Collins, Yuan Ping Thermal transport properties of warm dense matter affect the evolution of many systems, ranging from geodynamo in the Earth's core, to hydrodynamic instability growth in inertial confinement fusion (ICF) capsules. We report thermal conductivity measurements of CH and Be in the warm dense matter regime using x-ray differential heating and time-resolved refraction-enhanced radiography. The experiments were performed at the Omega laser facility. A cylindrically curved interface between CH and Be was isochorically heated by x-rays. The subsequent evolution of the interface was recorded by x-ray radiography with refraction enhanced contrast. A novel technique with an untrained deep neural network has been developed to retrieve the detailed interface profiles. The phase information can be decoded from one single intensity measurement when we apply physics constraints to the result. Multiple transport phenomena including thermal diffusion and wave propagation were revealed. The sensitivity of this radiographic technique to density gradients allows simultaneous constraints on the density, temperature and thermal conductivity. |
Monday, November 8, 2021 10:18AM - 10:30AM |
BO05.00005: High conductivity warm dense water excited by free-electron lasers Zhijiang Chen, Xieyu Na, Chandra Breanne Curry, Shujia Liang, Martin French, Adrien Descamps, Daniel Deponte, Jake Koralek, Jongjin Kim, Shay Lebovitz, Motoaki Nakatsutsumi, Benjamin K Ofori-Okai, Ronald A Redmer, Christian Roedel, Maximilian Schörner, Slawomir Skruszewicz, Philipp Sperling, Sven Toleikis, Mianzhen Mo, Siegfried Glenzer In this study, we measured the transient optical reflection and transmission of ultra-thin water sheet uniformly heated by 13.6 nm free-electron laser (FEL) approaching highly conducting states at electron temperatures exceeding 20,000 K. The experiment probes the trajectory of water through the high-energy density phase space and provides insights into the changes of the refractive index, charge carrier densities, and the electrical conductivity at optical frequencies. Significant specular reflection is observed due to the critical electron density shielding, indicating that the carrier electrons density is much higher than the FEL ionized electrons. At electron temperatures below 15,000 K, the experimental results agree well with the density-functional-theory molecular-dynamics simulations. With increasing temperature the electron system approaches a Fermi distribution. The conductivities agree better with predictions from the Ziman theory of liquid metals. |
Monday, November 8, 2021 10:30AM - 10:42AM |
BO05.00006: Stagnating Plasma-Piston Ramp Compression: A New Way to Measure Thermal Conductivity of Materials under Extreme Conditions Tyler M Perez, Raymond F Smith, Connor Krill, Dayne Fratanduono, Yuan Ping, Jon H Eggert, June K Wicks The thermal conductivity of iron at core pressure-temperature conditions (135-360 GPa, 2500-5000 K) is a key parameter for quantifying heat transport within the Earth's interior. An accurate measurement of this value has direct relevance for our understanding of multiple planetary processes, such as differentiation and generation of a magnetic field. However, both theoretical and experimental studies on the thermal conductivity of iron at core conditions are limited and not in agreement. At the OMEGA laser at the Laboratory for Laser Energetics (LLE), we use a recently developed stagnating plasma piston compression technique to smoothly and quasi-isentropically compress an iron sample to outer core conditions while simultaneously sending a thermal pulse through the iron. The sample consists of three planar targets of different thicknesses arranged in a stair-step pattern. By using a streaked optical pyrometer (SOP), we obtain time-resolved thermal emission curves from each step thickness on the side opposite to the heat source. These emission curves can be compared to the outputs of a finite element heat diffusion code in order to constrain thermal conductivity. Initial results suggest a moderately high value for thermal conductivity compared to most other experimental studies. |
Monday, November 8, 2021 10:42AM - 10:54AM |
BO05.00007: At the Nexus of Modelling and XFEL Experimental Design to Study Diffusion at Warm Dense Conditions. Tomorr Haxhimali, Robert E Rudd, James N Glosli, Liam G Stanton, Catherine Burcklen, Julia Vogel, Michael P Surh, Stefan P Hau-Riege Transport processes in warm dense matter such as diffusion remain poorly understood with considerable scatter between models and the absence of experimental data. We present results of modelling of diffusive interface broadening between diffusion couple materials in plasma generated in x-ray free electron laser (XFEL) experiments. |
Monday, November 8, 2021 10:54AM - 11:06AM |
BO05.00008: Constraining Multiphysics codes from ambient to warm dense matter using new radiation driven expansion data Kyle Cochrane, Patrick F Knapp, Nichelle L Bennett, Kristian Beckwith In order to ensure radiation hydrodynamic simulations are predictive, codes must be benchmarked against well characterized experimental data, preferably in the regime future experiments will performed. Alegra is a multiphysics code used to design many different experiments on Sandia’s Z machine. Data from a new platform on Z where the time-dependent expansion of an x-ray heated, tamped foil is measured via x-ray radiography is used to constrain Alegra’s IMC radiation hydrodynamics capability from solid, ambient conditions to the warm dense matter regime. |
Monday, November 8, 2021 11:06AM - 11:18AM |
BO05.00009: Methane Shock Compressed to 400 GPa Grigoriy Tabak, Thomas R Boehly, Gerrit Bruhaug, Gilbert Collins, Linda E Hansen, Brian Henderson, Margaret F Huff, Heather M Pantell, J. Ryan Rygg, Mohamed Zaghoo, Nathan M Dasenbrock-Gammon, Ranga P Dias, Marius Millot, Suzanne J Ali, Peter M Celliers, Jon H Eggert, Dayne E Fratanduono, Sebastien Hamel, Amy E Lazicki, Damian C Swift, Stephanie Brygoo, Paul Loubeyre, Ryosuke Kodama, Kohei Miyanishi, Tetsuo Ogawa, Norimasa Ozaki, Takayoshi Sano, Raymond Jeanloz, Damien G Hicks Methane plays an important role in planetary physics and is a major constituent of giant planet atmospheres. Methane is predicted to have an intricate phase diagram at high pressures, including the conditions inside planet interiors. [1-3] We present shock-compression data to 400 GPa for methane. The methane samples were precompressed in a diamond-anvil cell to a range of liquid and solid densities to access a broad range of extreme conditions. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856. [1] M. Ross, Nature 292, 435 (1981). [2] M. Ross and F. Rogers, Phys. Rev. B 74, 024103 (2006). [3] G. Gao et al., J. Chem. Phys. 133, 144508 (2010). |
Monday, November 8, 2021 11:18AM - 11:30AM |
BO05.00010: Recent measurements of warm dense samples heated directly by electrons Joshua E Coleman, James P Colgan, Chris J Fontes, Peter Hakel, Jason E Koglin, Heidi E Morris, Nick B Ramey, Dustin T Offermann The use of relativistic electrons from conventional accelerators for the study of WDM is not common practice. However, the heating mechanism is isochoric and the energy can be deposited into large volumes (> 20 mg and 2.5 x 10-3 cm3) of high-Z materials. Recent measurements have been made on 100-μm-thick samples ranging from 13Al to 79Au. A spatially resolved air-wedge shearing interferometer and shadowgraph diagnostic has been fielded to provide measurements of electron density (up to 8 x 1019 cm-3) with ~50 μm precision. This is a key diagnostic for understanding models of dense plasmas and is one of the tools used to benchmark our hydrodynamics model. This diagnostic can also provide a rough measurement of velocity which can be compared to photonic Doppler velocimetry. We are also developing diagnostics to provide detailed temperature measurements through the vapor dome. A spectroscopic quality radiation transport model has been developed to interpret the radiation output we measure from these dense plasmas. Example measurements on all of these fronts will be presented in comparison to some of our models. |
Monday, November 8, 2021 11:30AM - 11:42AM |
BO05.00011: Xray Thomson Scattering and Emission Spectroscopy as a Measurement of Non-thermal Electrons in Hot Dense Plasmas YuanFeng Shi, Sam M Vinko, Justin S Wark, Shenyuan Ren, Hae Ja Lee, Bob Nagler, Oliver Humphries, Eric Galtier When intense x-rays, such as those produced by an x-ray FEL, interact with a solid target to produce a plasma [1,2], electrons are excited into the continuum via photo-excitation and Auger decay, providing a controlled source of electrons that are well-defined in energy, being a function of the atomic properties of the target and the energy of the FEL beam. Owing to the dense nature of the system, these electrons rapidly thermalise due to collisional effects [3,4], yet during the FEL pulse itself, a non-thermal component of the electron distribution function will persist. In principle, information concerning the collisional dynamics and the evolution of the electron distribution function could be gleaned from a diagnosis of this non-thermal component, providing important insight into several aspects of the physics of dense plasmas. We present here an analysis of how such measurement might be obtained via the use of a combination of x-ray Thomson scattering and emission spectroscopy. Initial results are compared with simulations from the CCFLY code, and appear promising for further studies. |
Monday, November 8, 2021 11:42AM - 11:54AM |
BO05.00012: The First NLTE Gold Buried Layer Experiment on the NIF Edward V Marley, Christine M Krauland, Marilyn B Schneider, Duane A Liedahl, Gregory E Kemp, Mark E Foord, Yechiel R Frank An experiment has been done at the NIF using a buried layer platform to study the radiative properties of non-local thermodynamic equilibrium (NLTE) gold plasma at an electron temperature of ∼3 keV and an electron density of ∼1021cm-3. The targets used consisted of a 625 μm diameter, 1900 Å, thick dot with a 1:4.5 atomic mix of gold and zinc in the center of a 2500 μm diameter, 10 μm thick beryllium tamper. Lasers heat the target from both sides for 3.0 ns. The size of the microdot vs time was measured side-on with x-ray imaging. The radiant x-ray power was measured with a low-resolution, absolutely calibrated x-ray spectrometer (DANTE). The electron temperature was inferred from the measured zinc K-shell emission. The ionization balance of the gold is inferred from the measured L-shell emission of the gold. A comparison of the zinc K-shell spectrum and gold L-shell spectrum to the atomic kinetics code SCRAM is presented. |
Monday, November 8, 2021 11:54AM - 12:06PM |
BO05.00013: Measurements and radiation transport of emitted and absorbed spectral lines within an expanded, dense aluminum plasma Nicholas Ramey, Joshua E Coleman, Heidi E Morris, Peter Hakel, Chris J Fontes, James P Colgan, Jason E Koglin, Ronald M Gilgenbach, Ryan D McBride Emission and absorption lines have been measured within an expanded, dense aluminum plasma plume produced by electron beam isochoric heating of 100-um-thick aluminum foils. The intense, monochromatic electron beam (20 MeV, 1.45 kA, 80-ns FWHM) deposits approximately 5 J in a sub-1-mm FWHM spot, heating and subsequently expanding the material through the warm dense plasma phase [1]. A spectroscopic-quality radiation transport model [2] has been developed using inputs from a radiation-hydrodynamics code [3] along with the LANL suite of atomic physics codes [4] to provide a complete simulation capability for matching the experimental spectra. The resulting model has been benchmarked by visible interferometer measurements. New simulations predicting the EUV spectrum (< 200 nm) of the dense aluminum plasma plume are presented, along with the design and current status of a grazing-incidence EUV spectrometer that will be deployed to make the experimental measurements. A comparison between aluminum Sesame [5] EOS 3715 and 3720 for the radiation-hydrodynamics model is also discussed. |
Monday, November 8, 2021 12:06PM - 12:18PM |
BO05.00014: Probing Extreme Atomic Physics at Petapascal Pressures Suxing X Hu, Philip M Nilson, Valentin Karasiev, Igor E Golovkin, Ming Gu, Timothy Walton, Stephanie B Hansen Petapascal (~1015 Pa = 10 Gbar) pressures can be routinely accessible by inertial confinement fusion implosions due to compressions of both shock and spherical convergence. New atomic physics phenomena, such as interspecies radiative transitions,[1] might show up in superdense plasmas under extremely high pressures. A better understanding of such extreme atomic physics can, in turn, help diagnose high-energy-density plasmas. For these purposes, we have initiated a series of combined experimental and theoretical campaigns on OMEGA to examine detailed atomic physics at superhigh pressures using stable Cu-doped CH shell implosions. Time-resolved, high-resolution spectroscopy has been used to simultaneously measure Ka and Kb emission/absorption of Cu in the stagnating shell during the hot-spot formation. These observations have been interpreted by radiation-hydrodynamic simulations coupled with both commonly used collisional-radiative (NLTE) models and our newly developed VERITAS model that is based on density functional theory and multi-band kinetic modeling. We will present quantitative comparisons between experiments and simulations, with the expectation to establish a unified physics picture of how atoms behave in extremely high pressures. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856 and US National Science Foundation PHY Grant No. 1802964. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525. [1] S. X. Hu et al., Nat. Commun. 11, 1989 (2020). |
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