Bulletin of the American Physical Society
64th Annual Meeting of the APS Division of Plasma Physics
Volume 67, Number 15
Monday–Friday, October 17–21, 2022; Spokane, Washington
Session TO05: High-energy-density HydrodynamicsLive Streamed
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Chair: Pawel Kozlowski, LANL Room: Ballroom 111 B |
Thursday, October 20, 2022 9:30AM - 9:42AM |
TO05.00001: Effective Drift Velocity from Turbulent Transport by Vorticity in HED Flows Hussein Aluie, Shikhar Rai, Hao Yin, Aarne Lees, Dongxiao Zhao, Stephen Griffies, Jessica Shang We analyze turbulence transport generated by strong shocks. Using a systematic non-perturbative expansion due to Eyink [1], we show that unlike strain, which acts as an anisotropic diffusion/anti-diffusion tensor, vorticity's contribution is solely a conservative advection by an eddy-induced non-divergent velocity, v*, that is proportional to the curl of vorticity. Therefore, material (Lagrangian) advection of coarse-grained (in a hydro code) or under-resolved (in a lab measurement) quantities is accomplished not by the coarse-grained flow velocity, û, but by the effective velocity, û+v*. The physics of this effective transport is missing from current hydrodynamic models and may aid in the interpretation of data from experiments. |
Thursday, October 20, 2022 9:42AM - 9:54AM |
TO05.00002: Modeling shocks interacting with radiation waves in the Radishock experiment Shane X Coffing, Chris L Fryer, Forrest W Doss, Harry F Robey, Suzannah R Wood, Tom Byvank, Pawel Kozlowski, Heather M Johns, Christopher J Fontes, Andy S Liao, David D Meyerhofer, Todd J Urbatsch In the Radishock experiment, a radiation wave is indirectly driven into a low-density foam and interacts with a directly driven, counter-propagating shock. The interacting waves produce a spike in energy density, with a temperature greater than the local temperature of the individual waves. As in the successful predecessor experiment COAX, the primary diagnostic uses absorption spectroscopy at many locations down the cylindrical target, enabling a spatial temperature inference of the radiation wave and its interactions with the shock. Combined with a radiography diagnostic that is capable of imaging the shock and interaction features, we are able to study and inform model predictions of the interaction spike phenomenon. We present a physical description of these wave interactions and early comparisons between radiation-hydrodynamic simulations and the data from our successful experiments. |
Thursday, October 20, 2022 9:54AM - 10:06AM |
TO05.00003: Concerning ion temperature separation in multi-ion collisional plasma shocks Brett Keenan Polar-direct-drive exploding-pusher (PDXP) experiments are well suited to probe ion temperature separation effects. These campaigns show that — when inter-species thermalization time-scales are long1 — the ratios of inferred deuterium and tritium Tion values scale as the ratio of their respective ion masses. The origin of this mass-scaling is typically attributed to collisional shock physics. It is often (erroneously) claimed that Zel'dovich and Raizer3 (Z&R) predict a post-shock temperature that scales with species bulk (post-shock) kinetic energy; and therefore, is ∝ species mass. However, Z&R only claimed that the contribution to the total temperature jump across a shock, from viscous heating alone, scales with species kinetic energy — which we confirm here. Additionally, we show that the ion temperature is a complicated function of the total plasma viscosity, other ion temperatures, etc., and not ∝ ion mass. Finally, we propose an alternative (kinetic) explanation for the ion mass-scaling relationship observed in the PDXP experiments. |
Thursday, October 20, 2022 10:06AM - 10:18AM |
TO05.00004: Compression and Melt of Electrically Thick Metal Driven by a Mega-Ampere Current Pulse Aidan W Klemmer, Seth E Kreher, Bruno S Bauer, Trevor M Hutchinson, Dan Dolan, Andy Porwitzky, Thomas J Awe, Brian T Hutsel The electrothermal instability (ETI) is found in many fusion and HEDP experiments, dramatically affecting performance by seeding of MHD instabilities. Accurate modeling of the electrically driven conductors used in these experiments is challenging due to uncertainties in the equation of state and electrical conductivity, especially during the metal-insulator transition. Photonic Doppler velocimetry (PDV) was used to measure the surface motion of mm-diameter pure aluminum rods driven to 860 kA with 70 ns risetime (10-90%) by the Sandia Mykonos generator. For the first time, aluminum rods were measured to compress ~40 nm radially before expanding. The reflective surface experiences several changes in acceleration during the current pulse. PDV data was compared with MHD simulations to diagnose the phase-space trajectory of the metal surface, including magnetic compression, the duration of the solid-liquid phase transition, and the subsequent early-time motion until plasma formation, constraining the conditions from which ETI arises. |
Thursday, October 20, 2022 10:18AM - 10:30AM |
TO05.00005: Sensitivity of magnetohydrodynamic calculations to tabular equation of state models for pulsed power-driven metals Seth E Kreher The fundamental limits of high-current conduction in metals to large, fast current pulses are of interest to magnetically driven materials physics, thermonuclear fusion, and discovery science. MHD computer simulations adequately model the physics, but rely on an equation of state (EOS), and electrical conductivity (ECON) model to close the system of equations. The evolution of electrically thin wires (Rskin-depth, Ipeak~1 MA, t~100 ns) are simulated with historical and modern EOS/ECON models. Balance between internal energy and the Lorentz force constrains the material to the vaporization curve of the EOS for the bulk of the thin wires and at the surface of the thick rods. It is found that the variability in the slope of the vaporization curve due to uncertainty in the critical point has the greatest influence on the surface expansion velocity. In the case of thick rods, where PDV data has been fielded, calculations can be used to validate the EOS. |
Thursday, October 20, 2022 10:30AM - 10:42AM |
TO05.00006: CFD Modeling of Droplets Heated by an X-ray Free Electron Laser Claudia Parisuana-Barranca, David C Eder, Maxence Gauthier, Alice E Koniges, Jack McKee, Christopher Schoenwaelder, Claudiu A Stan, Siegfried H Glenzer High Energy Density (HED) Physics study matter under extreme states of pressure and temperature present in planetary interiors, astrophysical jets or fusion devices. Exciting data was obtained from single shot experiments recreating these conditions in laboratory using energetic laser/ion-beam drivers. In recent years, driven by the development towards high-repetition-rate drivers, collecting HED related data at a greater frequency is now within reach. For high-repetition-rate operation, liquid droplets can be used to provide a continuously refreshing target. However, one must make sure that extreme conditions produced during the preceding interaction and target debris do not degrade the next target. This is a challenging CFD problem that needs to model not only the initial dynamics of the heated droplet, but also the late time interaction with the following droplets. Here, the code PISALE is used to study the case of a liquid hydrogen droplet heated by an x-ray free electron laser. After showing high-resolution 2D results for a single heated droplet, we investigate in a 3D simulation the impact of the laser-droplet interaction on two subsequent droplets. We study the effect of surface tension on the droplets' deformation. |
Thursday, October 20, 2022 10:42AM - 10:54AM |
TO05.00007: Inferring viscosity from shock wave perturbation decay in laser-driven experiments Nitish Acharya, Danae Polsin, Jessica Shang, Hussein Aluie, Hadley Pantell, Afreen Syeda, Ryan Rygg, Gilbert W Collins, Peter M Celliers Sakharov et al. (1965) proposed an experimental approach to investigate the decaying oscillations of perturbed shock and determine the viscosity of a shocked material. Our study is borne out of interest to apply Sakharov’s method in laser driven experiments to deduce material viscosities at high energy density (HED) pressures. Here, we utilize the radiation hydrodynamics code FLASH to simulate the evolution of single-mode shock perturbation in polystyrene driven by laser ablation. We validate these simulations with a small set of experimental data (Endo et al.,1995) and analytical predictions (Miller et al., 1991 and Ishizaki et al.,1996). We further compare the two-dimensional inviscid simulations with Ishizaki’s model under varying shock pressures (300-900 GPa) and perturbation wavelengths and suggest a correction to the isentropic index to accurately model a non-ideal material like polystyrene. The corrected theoretical model shows excellent agreement with simulations increasing confidence in the predictive capabilities of FLASH. Next, we perform a sequence of viscous simulations with different perturbation wavelengths to quantify the effect of viscosities on the time-dependent shock amplitude and the velocity of shock front oscillations. In principle, the evolution of the shock perturbation amplitude can be measured by resolving the velocity history along a line in the material sample across a few wavelengths using line-VISAR in laser-driven experiments. Our simulation results indicate that VISAR may be capable of measuring such small velocity oscillations to infer viscosities of O (10 Pa-s). |
Thursday, October 20, 2022 10:54AM - 11:06AM |
TO05.00008: Experiments to study KH evolution of filaments feeding starburst galaxies on Omega-EP Adrianna Angulo, Shane X Coffing, Sallee R Klein, Matthew Trantham, Guy Malamud, Benjamin H Thompson, Assaf Shimony, Carolyn C Kuranz Galaxies need to accrete gas to form stars. Stars form near the center of the galactic halo within the galactic disc. The most proficient star forming galaxies, starburst galaxies, are those that involve filaments that withstand the shock that forms at the edge of the galactic halo and transport matter deep into the galactic disc. The cold, dense matter within the filament moves within the hot gaseous background, indicating that the filament boundary is likely Kelvin-Helmholtz (KH) unstable. If the KH instability is allowed enough time to evolve, it will potentially disrupt the filaments before they can penetrate deeply within the galaxy. Galactic scale simulations capable of modeling the filament dynamics lack the spatial resolution to capture these hydrodynamics. Therefore, we have conducted a scaled, high-energy-density laboratory experiment on the Omega-EP laser that emulates and studies the cosmological process of a cold stream penetrating a shocked region. We use a radiography diagnostic to observe the KH instability on the filament boundary and help tune hydrodynamic simulations performed using CRASH. From the data and tuned simulations, we determine whether the KH instability time-scale is relevant and to what extent it can inhibit mass delivery to the galactic disc. |
Thursday, October 20, 2022 11:06AM - 11:18AM |
TO05.00009: Experimental Design for Late Time Multimode Rayleigh-Taylor Instability with Controlled ablation effects Assaf Shimony, Heath J LeFevre, Sonya C Dick, Matthew Trantham, Guy Malamud, Eric Johnsen, Carolyn C Kuranz The asymptotic evolution of the Rayleigh-Taylor instability (RTI) is self-similar. Multimode RTI evolves when a supernova (SN) explodes onto the circumstellar medium (CSM). In the classical RTI (CRTI) case, the late time evolution is dominated by the bubble merger mechanism and independent of the initial perturbation. On the contrary, in the ablative RTI (ARTI) case, the evolution is dominated by the bubble competition mechanism and depends on the initial perturbation. This qualitative difference between these mechanisms can impact the mix width at late times. |
Thursday, October 20, 2022 11:18AM - 11:30AM |
TO05.00010: Energy Transport and Thermodynamics in Compressive Laser-Driven Implosion Experiments Ethan Smith, David A Chin, David T Bishel, Connor A Williams, Neel V Kabadi, Chad J Forrest, Vladimir Y Glebov, Gilbert W Collins, J. Ryan Rygg, John J Ruby In implosions of thick, gas-filled shells, such as those used in inertial confinement fusion experiments, the emitted radiation is determined by the thermodynamic states and energy transport properties of both the compressed gas and dense shell. Consequently, these implosions provide a platform for the study of these material properties at gigabar pressures through detailed measurement and integrated analysis of the emitted radiation. We present the results of laser-driven spherical implosions at the OMEGA Laser Facility of 860 µm outer-diameter, 20-35 µm thick plastic shells with 20-atm warm deuterium fill. A suite of measurements of x-ray self-emission and D-D neutron production, along with a parameterized reduced-physics model are used to constrain the thermodynamic states and energy transport in the implosion. |
Thursday, October 20, 2022 11:30AM - 11:42AM |
TO05.00011: Three-Dimensional Simulations of Machined Perturbation Profiles Subjected to the Richtmyer-Meshkov Instability: Mix Metrics Analysis and Comparison to Experiments Sam L Pellone, Carlos A Di Stefano, Alexander M Rasmus, Elizabeth C Merritt, Forrest W Doss Shock-driven hydrodynamic instabilities play a major role in the performance of inertial confinement fusion targets. The presence of surface roughness in these targets, e.g., from machining, seeds instability growth, potentially leading to turbulence and mixing, degrading the conditions necessary to achieve thermonuclear burn. Recent data from the ModCons experimental campaign — performed on Omega EP with a singly shocked heavy-to-light interface (plastic and foam) — has observed shot-to-shot differences between six shots of the same nominal perturbation profile, suggesting that small variations in target fabrication may be important in the late-time turbulence and mixing. In this work, we simulate the evolution of three-dimensional surface roughness for these six machined perturbation profiles using the LANL code xRAGE. The results of the 3D simulations are then averaged out (in space) to produce 2D maps of mix metrics such as the density-specific volume covariance. The analysis is further quantified by comparing to 2D simulations with the BHR turbulence model. |
Thursday, October 20, 2022 11:42AM - 11:54AM |
TO05.00012: Ensemble turbulence experiments in the HED regime Alexander M Rasmus, Sam L Pellone, Carlos A Di Stefano, Forrest W Doss, Kirk A Flippo, Joseph M Levesque, Elizabeth C Merritt Hydrodynamic instabilities are ubiquitous on interfaces that interact with shocks. These instabilities are often seeded by surface roughness that is too computationally expensive to resolve directly. Furthermore, the instability growth is often initially laminar, so that the best way to initialize sub-grid turbulence models (such as LANL’s BHR) isn’t readily apparent. Recent campaigns in the HED regime have used spanwise spatial lineout averaging when calculating turbulence quantities such as “b”, the density-specific volume covariance. Most turbulence models are validated against fully developed turbulence and thus insensitive to the type of averaging used. However, during the transition to turbulence the type of averaging used may be an important consideration when comparing experiments to turbulence models. Here, we will present Omega-EP experiments in which a nominally identical single mode perturbation (up to surface roughness), heavy-to-light, RM with delayed onset RT experiment was repeated multiple times to generate an ensemble dataset, over which ensemble averaging may be used to calculate 2D distributions of turbulence quantities. A related talk by S. Pellone will discuss 3D simulations initialized based on detailed pre-shot characterizations of interface perturbations. |
Thursday, October 20, 2022 11:54AM - 12:06PM |
TO05.00013: Ablation of a solid obstacle with a radiative shock driven by gas gun plate impact Emilio Escauriza, Rosie Barker, Martin Read, Guy C Burdiak, Hugo W Doyle, Nicholas Hawker Radiative ablation of solid obstacles by a radiating shock in low-pressure gas has previously been observed in laser-driven experiments [T. Vinci et al., Phys. Plasmas 13, 2006; M. Koenig et al., Phys. Plasmas 24, 2017]. At First Light Fusion Ltd, we are motivated to study the phenomena in relation to our ‘projectile fusion’ research, where solid surfaces in our targets are irradiated by shocks propagating through low-pressure gas mixtures. Experimental data of this effect is needed to benchmark our in-house radiation hydrodynamics code Hytrac. |
Thursday, October 20, 2022 12:06PM - 12:18PM |
TO05.00014: Reshocked Rayleigh-Taylor instabilities experiments on ORION Alexis Casner, Charlotte A Palmer, Gabriel Rigon, Victorien Bouffetier, Luke CEURVORST, Philip BRADFORD, Gianluca Gregori, Michel Koenig, Chris Spindloe, Paul Mabey, Bruno Albertazzi, John Foster We report on Reshocked Rayleigh-Taylor Instability (RTI) experiments fielded on the ORION laser. These experiments build from a platform qualified on the LULI2000 facility which allowed to perform High Energy Density (HED) experiments in scaled conditions for Supernovae Remnants evolution [1]. A low density foam is used to trigger the RTI in deceleration, creating a well-developed mixing layer. The mixing zone width is diagnosed by x-ray point-projection radiography. On ORION, we benefit from the double-sided laser illumination to increase the level of mixing. The mixing zone is reshocked by a shock launched from the opposite side of the target. Re-shocking an already developed mixing zone is predicted to enhance the generation of turbulence, in shock tube or laser-driven experiments. We develop an HED analogue of RTI shock tube studies and study the influence of initial conditions on the mixing zone width evolution. Such highly nonlinear HED flows provide stringent benchmarks for radiation-magnetohydrodynamics code [2]. Our results will be compare against FLASH simulations and we will present the path forward to larger scale laser facilities. |
Thursday, October 20, 2022 12:18PM - 12:30PM |
TO05.00015: A new experimental platform to study high-energy density rotating plasmas on the OMEGA laser Francisco Suzuki-Vidal, George F Swadling, Mathieu Bailly-Grandvaux, Vicente Valenzuela-Villaseca, Chris A Walsh We present first results on the formation of rotating plasma flows at the OMEGA laser to model physics relevant to accretion disks and jets in astrophysics. The experiments consist of a circular array of six V-shaped targets 3-D printed in CH in a diameter of approx. 12 mm and with a 5 degree offset respect to the axis of the array. The target package is illuminated with 12 beams, each with approx. 500 J and a 1 ns duration, leading to the formation of six radial jets propagating slightly off axis towards the centre of the array, driving a rotating plasma disk. |
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