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 NO7: High-Energy Density Hydrodynamics |
Hide Abstracts |
Chair: Harry Robey, Lawrence Livermore National Laboratory Room: 203 |
Wednesday, November 18, 2015 9:30AM - 9:42AM |
NO7.00001: Establishing the Transition to Turbulence in HED Shear Experiments on the NIF Kirk Flippo, F.W. Doss, J.L. Kline, L. Kot, T.S. Perry, B. Devolder, T.J. Murphy, E.N. Loomis, E.C. Merritt, D.W. Schmidt, D. Capelli, T. Cardenas, R.B. Randolph, F. Fierro, G. Rivera, C.M. Huntington, S.R. Nagel, S.A. MacLaren We report on hydrodynamic experiments performed at the NIF to investigate turbulent mixing in a High Energy Density (HED) r\'{e}gime using the LANL Shock/Shear platform. We investigate turbulence-driven mix from a counter-propagating shear-flow induced Kelvin- Helmholtz instability. Such flows may be present in an ICF capsule that has low-mode asymmetries and bulk mixing of the shell into the fuel. In the NIF LANL Shear experiment two shocks are generated at either end of cylinder, inside which CH foams act as a light fluid and the evolution of a tracer layer (a ``heavy fluid'') in the center plane is imaged using the Big Area Backlighter (BABL), a large area x-ray backlighter, developed for this project. Edge views of the tracer layer are studied to quantify growth of the mix layer into the foam. Additionally, plan views (90-degrees to the edge view) are imaged to look at the complex hydrodynamic behavior of the foil, revealing coherent structures like rollers and wigglers similar to those seen in dye marker pure fluid shear experiments, features that can be made to evolve quickly into a state of randomness when the foil is roughened. [Preview Abstract] |
Wednesday, November 18, 2015 9:42AM - 9:54AM |
NO7.00002: Mode growth experiments using single-mode initial conditions in a counter-propagating shear experiment on OMEGA E.C. Merritt, C.A. Di Stefano, F.W. Doss, K.A. Flippo, E.N. Loomis, J.L. Kline Counter-propagating (CP) shear experiments conducted on OMEGA are evaluating the effect of target initial conditions, specifically the characteristics of a tracer foil at the shear boundary, on shear instability evolution in the high-energy-density (HED) regime. Experiments are designed to both examine the dependence of the model initial turbulent parameters in turbulence models of k-$\varepsilon $ type on competing physical instability seed lengths as well as develop a path toward turbulent HED experiments. Previous experiments [1,2] focused on instability growth from multi-mode initial conditions due to the natural roughness of an un-perturbed tracer foil. Recent observation of emergent coherent structures in the NIF CP shear experiments [3] emphasize the need to understand the mode growth dynamics of this type of shear system, one with an initially stationary separation layer between the flows. To this end, we will present results of recent single-mode mode growth studies on OMEGA using sinusoidal tracer layers at several different wavelengths.\\[4pt] [1] Doss \textit{et al}., Phys. Plasmas \textbf{20}, 012707 (2013)\\[0pt] [2] Merritt \textit{et al}., Phys. Plasmas \textbf{22}, 062306 (2015)\\[0pt] [3] Doss \textit{et al}., Phys. Plasmas \textbf{22}, 056303 (2015). [Preview Abstract] |
Wednesday, November 18, 2015 9:54AM - 10:06AM |
NO7.00003: Design and simulation of high-energy-density shear experiments on OMEGA and the NIF F.W. Doss, B. DeVolder, C. Di Stefano, K.A. Flippo, J.L. Kline, L. Kot, E.N. Loomis, E.C. Merritt, T.S. Perry, S.A. MacLaren, P. Wang, Y.K. Zhou High-energy-density shear experiments have been performed by LANL at the OMEGA Laser Facility and National Ignition Facility (NIF). The experiments have been simulated using the LANL radiation-hydrocode RAGE and have been used to assess turbulence models' ability to function in the high-energy-density, inertial-fusion-relevant regime. Beginning with the basic configuration of two counter-oriented shock-driven flows of $>$~100~km/s, which initiate a strong shear instability across an initially solid density, 20~micron thick Al plate, variations of the experiment have been performed and are studied. These variations have included increasing the fluid density (by modifying the metal plate material from Al to Ti), imposing sinusoidal perturbations on the plate, and directly modifying the plate's intrinsic surface roughness. In addition to examining the shear-induced mixing, the simulations reveal other physics, such as how the interaction of our indirect-drive halfraums with a mated shock tube's ablator impedes a stagnation-driven shock. [Preview Abstract] |
Wednesday, November 18, 2015 10:06AM - 10:18AM |
NO7.00004: Evidence of foam interpenetration in unloading, shocked reservoirs at the National Ignition Facility Shon Prisbrey, Hye-Sook Park, Robin Benedetti, Peter Graham, Channing Huntington, James McNaney, Raymond Smith, Chris Wehrenberg, Cynthia Panas, Angela Cook, Michael Wilson, Bruce Remington, A. Arsenlis Shocked reservoirs that have unloaded across a gap can create a pressure profile upon stagnation. The pressure profile can be tailored to some degree by changing the initial thickness, density, and material components of the reservoir prior to shock loading. We have previously shown that the drive created by each component of the reservoir can be inferred from a velocity history measurement made at the back of a thin ($\sim$ 15 $\mu$m) drive plate placed at the stagnation side of the gap. Recent measurements of lower density, carbonized resorcinol formaldehyde foam indicates a density threshold below which individual foam layers no longer create a step in the velocity history but create a continuous increase in the velocity. We will present drive results from recent experiments on the National Ignition Facility and the required density profiles needed in simulation to match the experiment which indicate that substantial mixing/interpenetration is occurring during the shock loading of the lowest density foam layer. [Preview Abstract] |
Wednesday, November 18, 2015 10:18AM - 10:30AM |
NO7.00005: Development of a low-adiabat drive for material science experiments on NIF using release and recompression of low density organic foams Christopher Wehrenberg, Shon T. Prisbrey, Hye-Sook Park, L. Robin Benedetti, Channing Huntington, James McNaney, Ray Smith, Cynthia Panas, Angela Cook, Bruce Remington, Tom Arsenlis, Peter Graham A series of experiments were performed on NIF to develop a planar, 3-shock, low-adiabat drive for material science experiments. Physics samples (Ta, Pb, etc.) are loaded to 3-4 Mbar while staying well below the melt temperature. X-ray ablation from an indirect drive launches a strong ($\sim$ 50 Mbar), decaying shock through a precision fabricated ``reservoir,'' consisting of a CH ablator, followed by layers of Al, CH(18.75{\%}I), $\sim$ 375 mg/cc carbonized resorcinol formaldehyde foam, and a final layer of low density (10-35) mg/cc foam. As the releasing reservoir stagnates on a Ta drive plate, VISAR is used to measures the resulting compression waves. The lowest density reservoir layer is responsible for the leading shock and induces the most entropy during the drive. LLNL has developed a new, low-density foam called JX6 (C$_{20}$H$_{30}$) for the purpose of controlling the leading shock. We will describe a series of experiments done on NIF to test the combined release and recompression properties of JX6 and to develop a new, lower-adiabat drive. [Preview Abstract] |
Wednesday, November 18, 2015 10:30AM - 10:42AM |
NO7.00006: Experimental Results of High Pressure and High Strain Rate Tantalum Flow Stress on Omega and NIF Hye-Sook Park, A. Arsenlis, N. Barton, L. Benedetti, C. Huntington, J. McNaney, D. Orlikowski, S. Prisbrey, B. Remington, R. Rudd, D. Swift, S. Weber, C. Wehrenberg, A. Comley Understanding the high pressure, high strain rate plastic deformation dynamics of materials is an area of research of high interest to planetary formation dynamics, meteor impact dynamics, and inertial confinement fusion designs. Developing predictive theoretical and computational descriptions of such systems, however, has been a difficult undertaking. We have performed many experiments on Omega [1], LCLS and NIF to test Ta strength models at high pressures ($\sim$ up to 4 Mbar), high strain rates ($\sim$ 10$^{7}$ s$^{-1})$ and high strains (\textgreater 30{\%}) under ramped compression conditions using Rayleigh-Taylor and Richtmyer-Meshkov instability properties. These experiments use plasma drive to ramp compress the sample to higher pressure without shock-melting. We also studied lattice level strength mechanisms under shocked compression using a diffraction-based technique. Our studies show that the strength mechanisms from macro to micro scales are different from the traditional strength model predictions and that they are loading path dependent. We will report the experimental results.\\[4pt] [1] H. --S. Park et al., Phys. Rev. Lett. 114, 065502 (2015). [Preview Abstract] |
Wednesday, November 18, 2015 10:42AM - 10:54AM |
NO7.00007: Comparing Hydrodynamic simulations to Rayleigh-Taylor Instability Experiments at High pressure and at high strain rates for tantalum: constraining strength models* Daniel Orlikowski, A. Arsenlis, N. Barton, L.R. Benedetti, A. Comley, C.M. Huntington, J.M. McNaney, H.S. Park, S.T. Prisbrey, D. Swift, S.V. Weber, R.E. Rudd, C.E. Wehrenberg High pressure strength modeling has long been an outstanding problem affecting many design applications, like inertial confinement fusion experiments. Recently Rayleigh-Taylor Instability (RTI) experiments on tantalum at pressures (\textgreater 3 Mbar) and at strain rates ($\sim$ 10$^{7}$ s$^{-1})$ have been achieved at National Ignition Facility. These highly resolved measurements of the early growth of the sinusoidal perturbations in Ta are compared to hydrodynamic simulations with different strength models and parameters. At LLNL we have developed a multi-scale strength (LMS) model based on calculations and simulations spanning length scales from atomistic, to dislocations, to continuum. Simulations of the RTI based on the LMS model are comparable to the experimental growth factors at modest pressures ($\sim$ 1 Mbar), whereas traditional strength models are too weak to capture the RTI growth. However, current experimental growth factors at \textgreater 3 Mbar indicate that the parameterization from lower pressures is not adequate to simulate these higher pressure experiments. We discuss here the insights that these experiments provide to our high pressure strength modeling effort. *Work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA273 [Preview Abstract] |
Wednesday, November 18, 2015 10:54AM - 11:06AM |
NO7.00008: Using Omega and NIF to Advance Theories of High-Pressure, High-Strain-Rate Tantalum Plastic Flow R.E. Rudd, A. Arsenlis, N.R. Barton, R.M. Cavallo, C.M. Huntington, J.M. McNaney, D.A. Orlikowski, H.-S. Park, S.T. Prisbrey, B.A. Remington, C.E. Wehrenberg Precisely controlled plasmas are playing an important role as both pump and probe in experiments to understand the strength of solid metals at high energy density (HED) conditions. In concert with theory, these experiments have enabled a predictive capability to model material strength at Mbar pressures and high strain rates [1]. Here we describe multiscale strength models developed for tantalum and vanadium starting with atomic bonding and extending up through the mobility of individual dislocations, the evolution of dislocation networks and so on up to full scale [2]. High-energy laser platforms such as the NIF and the Omega laser probe ramp-compressed strength to 1-5 Mbar [3,4]. The predictions of the multiscale model agree well with the 1 Mbar experiments without tuning [4]. The combination of experiment and theory has shown that solid metals can behave significantly differently at HED conditions; for example, the familiar strengthening of metals as the grain size is reduced has been shown not to occur in the high pressure experiments [4]. [1] R.E. Rudd et al., MRS Bull. 35, 999 (2010). [2] N.R. Barton et al., J. Appl. Phys. 109, 073501 (2011). [3] H.-S. Park et al., Phys. Rev. Lett. 104, 135504 (2010). [4] H.-S. Park et al., Phys. Rev. Lett. 114, 065502 (2015). [Preview Abstract] |
Wednesday, November 18, 2015 11:06AM - 11:18AM |
NO7.00009: Material Strength Effects on Feedthru of the Ablative Richtmyer-Meshkov Instability Eric Loomis, Pedro Peralta, Elizabeth Fortin, Jenna Lynch Mitigating hydrodynamic instabilities in Inertial Confinement Fusion (ICF) is of prime importance for producing self-heating and reaching ignition. One possible mitigation strategy involves the use of metal ablators (e.g., Be) that remain solid following passage of the first shock. Finite material strength in these capsules would alter the feedthru characteristics (oscillation frequency and decay rate) of perturbations initially on the outer surface. To study the physics associated with material strength effects on rippled shock oscillations and feedthru, experiments were performed at the Los Alamos Trident laser. These experiments directly measured the surface height amplitude imprinted by the shock ripple at the opposite free surface with 20 nm precision over a timespan of 25 ns using an in-situ diagnostic called Transient Imaging Displacement Interferometry (TIDI). Simulations from the Lawrence Livermore National Lab code HYDRA predicted that the free surface ripple grows about 3 times more without the use of a strength model in Cu for an initial 5 micron amplitude, 50 micron wavelength sinusoid driven to a free surface velocity of 600 m/s. By increasing the perturbation wavelength we slowed the shock oscillation frequency and decay rate to increase the free surface ripple amplitude to roughly half the perturbations initial amplitude. The time dependent imprinted amplitude was considerably less in high strength Fe versus the softer Cu. [Preview Abstract] |
Wednesday, November 18, 2015 11:18AM - 11:30AM |
NO7.00010: Investigating shock-driven Richtmyer-Meshkov ripple evolution before and after re-shock S.R. Nagel, C.M. Huntington, S.A. MacLaren, K.S. Raman, T. Baumann, L.R. Benedetti, D.M. Doane, T.S. Islam, S. Felker, J.P. Holder, R.M. Seugling, P. Wang, Y.K. Zhou, F.W. Doss, K.A. Flippo, T.S. Perry Late-time Rayleigh-Taylor/Richtmyer-Meshkov(RM) ripple growth in an opposing-shock geometry is investigated using x-ray area backlit imaging of a shock-tube with indirectly driven shocks. The shocks are driven from opposing sides of the tube. The ablator layer on one side has pre-imposed ripples in the form of a sine wave with two amplitudes and a single wavelength. This ablator includes an opaque tracer layer that is used to track the perturbed interface as it is driven into a lower density foam. The ablator on the opposing side of the tube is flat, and is used to launch the shock that re-shocks the rippled interface. A large-area backlighter and gated x-ray radiography is used to capture images at different times during the RM instability growth. Here, first measurements obtained with this experimental platform at the NIF, including the optimization of the platform are presented. The RM ripple evolution before and after re-shock, including a possible loss of initial conditions are, also discussed. The data that informs the codes is compared to simulation results [Preview Abstract] |
Wednesday, November 18, 2015 11:30AM - 11:42AM |
NO7.00011: ABSTRACT WITHDRAWN |
Wednesday, November 18, 2015 11:42AM - 11:54AM |
NO7.00012: Hydrodynamic Instabilities at an Oblique Interface Carolyn Kuranz, Carlos Di Stefano, W.C. Wan, R.P. Drake, G. Malamud, A. Shimony, D. Shvarts Hydrodynamic instabilities are an important phenomenon that have consequences in many high-energy-density systems, including astrophysical systems and inertial confinement fusion experiments. Using the Omega EP laser we have created a sustained shock platform to drive a steady shock wave using a $\sim$ 30 ns laser pulse. Coupled with a Spherical Crystal Imager we have created high-resolution x-ray radiographs to diagnose the evolution of complex hydrodynamic structures. This experiment involves a hydrodynamically unstable interface at an oblique angle so that the Richtmyer-Meshkov and Kelvin-Helmholtz processes are present. A dual-mode perturbation is machined onto the interface and we seek to observe the merging of vertical structures. Preliminary data from recent experiments and simulations results will be shown. \\[4pt] This work is funded by the U.S. Department of Energy, through the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-NA0001840, and the National Laser User Facility Program, grant number DE-NA0002032 and through the Laboratory for Laser Energetics, University of Rochester by the NNSA/OICF under Cooperative Agreement No. DE-NA0001944. [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