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526 results on '"Hansen, S. B."'

1. Radiatively Cooled Magnetic Reconnection Experiments Driven by Pulsed Power

Author

Datta, R, Chandler, K, Myers, C E, Chittenden, J P, Crilly, A J, Aragon, C, Ampleford, D J, Banasek, J T, Edens, A, Fox, W R, Hansen, S B, Harding, E C, Jennings, C A, Ji, H, Kuranz, C C, Lebedev, S V, Looker, Q, Patel, S G, Porwitzky, A J, Shipley, G A, Uzdensky, D A, Yager-Elorriaga, D A, and Hare, J D

Subjects
Physics - Plasma Physics
Abstract

We present evidence for strong radiative cooling in a pulsed-power-driven magnetic reconnection experiment. Two aluminum exploding wire arrays, driven by a 20 MA peak current, 300 ns rise time pulse from the Z machine (Sandia National Laboratories), generate strongly-driven plasma flows ($M_A \approx 7$) with anti-parallel magnetic fields, which form a reconnection layer ($S_L \approx 120$) at the mid-plane. The net cooling rate far exceeds the Alfv\'enic transit rate ($\tau_{\text{cool}}^{-1}/\tau_{\text{A}}^{-1} > 100$), leading to strong cooling of the reconnection layer. We determine the advected magnetic field and flow velocity using inductive probes positioned in the inflow to the layer, and inflow ion density and temperature from analysis of visible emission spectroscopy. A sharp decrease in X-ray emission from the reconnection layer, measured using filtered diodes and time-gated X-ray imaging, provides evidence for strong cooling of the reconnection layer after its initial formation. X-ray images also show localized hotspots, regions of strong X-ray emission, with velocities comparable to the expected outflow velocity from the reconnection layer. These hotspots are consistent with plasmoids observed in 3D radiative resistive magnetohydrodynamic simulations of the experiment. X-ray spectroscopy further indicates that the hotspots have a temperature (170 eV) much higher than the bulk layer ($\leq$ 75 eV) and inflow temperatures (about 2 eV), and that these hotspots generate the majority of the high-energy (> 1 keV) emission.

Published
2024

2. Plasmoid formation and strong radiative cooling in a driven magnetic reconnection experiment

Author

Datta, R., Chandler, K., Myers, C. E., Chittenden, J. P., Crilly, A. J., Aragon, C., Ampleford, D. J., Banasek, J. T., Edens, A., Fox, W. R., Hansen, S. B., Harding, E. C., Jennings, C. A., Ji, H., Kuranz, C. C., Lebedev, S. V., Looker, Q., Patel, S. G., Porwitzky, A., Shipley, G. A., Uzdensky, D. A., Yager-Elorriaga, D. A., and Hare, J. D.

Subjects
Physics - Plasma Physics
Abstract

We present results from the first experimental study of strongly radiatively-cooled magnetic reconnection. Two exploding aluminum wire arrays, driven simultaneously by the Z machine ($I_{max} = 20 \, \text{MA}$, $t_{\text{rise}} = 300 \, \text{ns}$), generate a radiatively-cooled reconnection layer ($S_L \approx 120$) in which the total cooling rate exceeds the hydrodynamic transit rate ($\tau_{\text{hydro}}/\tau_{\text{cool}} > 100$). Measurements of X-ray emission from the reconnection layer using a filtered diode ($>1$ keV) show a narrow (50 ns FWHM) burst of emission at 220 ns after current start, consistent with the formation and subsequent rapid cooling of the reconnection layer. Time-gated X-ray images of the reconnection layer show fast-moving (up to 50 km/s) hotspots inside the layer, consistent with the presence of plasmoids observed in 3D resistive magnetohydrodynamic simulations. X-ray spectroscopy shows that these hotspots generate the majority of Al K-shell emission (at around 1.6 keV) prior to the onset of cooling, and exhibit temperatures of 170 eV, much greater than the temperature of the plasma inflows and the rest of the reconnection layer.

Published
2024

3. Review of the First Charged-Particle Transport Coefficient Comparison Workshop

Author

Grabowski, P. E., Hansen, S. B., Murillo, M. S., Stanton, L. G., Graziani, F. R., Zylstra, A. B., Baalrud, S. D., Arnault, P., Baczewski, A. D., Benedict, L. X., Blancard, C., Certik, O., Clerouin, J., Collins, L. A., Copeland, S., Correa, A. A., Dai, J., Daligault, J., Desjarlais, M. P., Dharma-wardana, M. W. C., Faussurier, G., Haack, J., Haxhimali, T., Hayes-Sterbenz, A., Hou, Y., Hu, S. X., Jensen, D., Jungman, G., Kagan, G., Kang, D., Kress, J. D., Ma, Q., Marciante, M., Meyer, E., Rudd, R. E., Saumon, D., Shulenburger, L., Singleton Jr., R. L., Sjostrom, T., Stanek, L. J., Starrett, C. E., Ticknor, C., Valaitis, S., Venzke, J., and White, A.

Subjects
Physics - Plasma Physics
Abstract

We present the results of the first Charged-Particle Transport Coefficient Code Comparison Workshop, which was held in Albuquerque, NM October 4-6, 2016. In this first workshop, scientists from eight institutions and four countries gathered to compare calculations of transport coefficients including thermal and electrical conduction, electron-ion coupling, inter-ion diffusion, ion viscosity, and charged particle stopping powers. Here, we give general background on Coulomb coupling and computational expense, review where some transport coefficients appear in hydrodynamic equations, and present the submitted data. Large variations are found when either the relevant Coulomb coupling parameter is large or computational expense causes difficulties. Understanding the general accuracy and uncertainty associated with such transport coefficients is important for quantifying errors in hydrodynamic simulations of inertial confinement fusion and high-energy density experiments., Comment: 45 pages, 17 figures

Published
2020
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5. Review of the 10th Non-LTE Code Comparison Workshop

Author

Hansen, S. B., Chung, H. -K., Fontes, C. J., Ralchenko, Yu., Scott, H. A., and Stambulchik, E.

Subjects
Physics - Plasma Physics
Abstract

We report on the results of the 10th Non-LTE code comparison workshop, which was held at the University of San Diego campus November 28 through December 1, 2017. Non-equilibrium collisional-radiative models predict the electronic state populations and attendant emission and absorption characteristics of hot, dense matter and are used to help design and diagnose high-energy-density experiments. At this workshop, fifteen codes from eleven institutions contributed results for steady-state and time-dependent neon, aluminum, silicon, and chlorine cases relevant to a variety of high-density experimental and radiation-driven astrophysical systems. This report focuses on differences in the predictions from codes with different internal structure, completeness, density effects, and rate fidelity and the impact of those differences on hot, dense plasma diagnostics., Comment: submitted to HEDP

Published
2019
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6. Radiatively cooled magnetic reconnection experiments driven by pulsed power

Author

Datta, R., primary, Chandler, K., additional, Myers, C. E., additional, Chittenden, J. P., additional, Crilly, A. J., additional, Aragon, C., additional, Ampleford, D. J., additional, Banasek, J. T., additional, Edens, A., additional, Fox, W. R., additional, Hansen, S. B., additional, Harding, E. C., additional, Jennings, C. A., additional, Ji, H., additional, Kuranz, C. C., additional, Lebedev, S. V., additional, Looker, Q., additional, Patel, S. G., additional, Porwitzky, A., additional, Shipley, G. A., additional, Uzdensky, D. A., additional, Yager-Elorriaga, D. A., additional, and Hare, J. D., additional

Published
2024
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7. Plasmoid Formation and Strong Radiative Cooling in a Driven Magnetic Reconnection Experiment

Author

Datta, R., primary, Chandler, K., additional, Myers, C. E., additional, Chittenden, J. P., additional, Crilly, A. J., additional, Aragon, C., additional, Ampleford, D. J., additional, Banasek, J. T., additional, Edens, A., additional, Fox, W. R., additional, Hansen, S. B., additional, Harding, E. C., additional, Jennings, C. A., additional, Ji, H., additional, Kuranz, C. C., additional, Lebedev, S. V., additional, Looker, Q., additional, Patel, S. G., additional, Porwitzky, A., additional, Shipley, G. A., additional, Uzdensky, D. A., additional, Yager-Elorriaga, D. A., additional, and Hare, J. D., additional

Published
2024
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8. Comment on 'Large enhancement in high-energy photoionization of Fe XVII and missing continuum plasma opacity'

Author

Blancard, C., Colgan, J., Cossé, Ph., Faussurier, G., Fontes, C. J., Gilleron, F., Golovkin, I., Hansen, S. B., Iglesias, C. A., Kilcrease, D. P., MacFarlane, J. J., More, R. M., Pain, J. -C., Sherrill, M., and Wilson, B. G.

Subjects
Physics - Atomic Physics, Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics
Abstract

Recent R-matrix calculations claim to produce a significant enhancement in the opacity of Fe XVII due to atomic core excitations [S. N. Nahar & A.K. Pradhan, Phys. Rev. Letters 116, 235003 (2016), arXiv:1606.02731] and assert that this enhancement is consistent with recent measurements of higher-than-predicted iron opacities [J. E. Bailey et al., Nature 517, 56 (2015)]. This comment shows that the standard opacity models which have already been directly compared with experimental data produce photon absorption cross-sections for Fe XVII that are effectively equivalent to (and in fact larger than) the new R-matrix opacities. Thus, the new R-matrix results cannot be expected to significantly impact the existing discrepancies between theory and experiment because they produce neither a "large enhancement" nor account for "missing continuum plasma opacity" relative to standard models., Comment: three pages, one table, one figure

Published
2016
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9. Exploring magnetized liner inertial fusion with a semi-analytic model

Author

McBride, R. D., Slutz, S. A., Vesey, R. A., Gomez, M. R., Sefkow, A. B., Hansen, S. B., Knapp, P. F., Schmit, P. F., Geissel, M., Harvey-Thompson, A. J., Jennings, C. A., Harding, E. C., Awe, T. J., Rovang, D. C., Hahn, K. D., Martin, M. R., Cochrane, K. R., Peterson, K. J., Rochau, G. A., Porter, J. L., Stygar, W. A., Campbell, E. M., Nakhleh, C. W., Herrmann, M. C., Cuneo, M. E., and Sinars, D. B.

Subjects
Physics - Plasma Physics
Abstract

In this paper, we explore magnetized liner inertial fusion (MagLIF) [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)] using a semi-analytic model [R. D. McBride and S. A. Slutz, Phys. Plasmas 22, 052708 (2015)]. Specifically, we present simulation results from this model that: (a) illustrate the parameter space, energetics, and overall system efficiencies of MagLIF; (b) demonstrate the dependence of radiative loss rates on the radial fraction of the fuel that is preheated; (c) explore some of the recent experimental results of the MagLIF program at Sandia National Laboratories [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)]; (d) highlight the experimental challenges presently facing the MagLIF program; and (e) demonstrate how increases to the preheat energy, fuel density, axial magnetic field, and drive current could affect future MagLIF performance., Comment: Published in Physics of Plasmas [http://dx.doi.org/10.1063/1.4939479]

Published
2015
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10. Phase retrieval for refraction-enhanced x-ray radiography using a deep neural network.

Author

Jiang, S., Landen, O. L., Whitley, H. D., Hamel, S., London, R. A., Sterne, P., Hansen, S. B., Hu, S. X., Collins, G. W., and Ping, Y.

Subjects
ARTIFICIAL neural networks, RADIOGRAPHY, X-ray absorption, X-rays, ALGORITHMS
Abstract

X-ray refraction-enhanced radiography (RER) or phase contrast imaging is widely used to study internal discontinuities within materials. The resulting radiograph captures both the decrease in intensity caused by material absorption along the x-ray path, as well as the phase shift, which is highly sensitive to gradients in density. A significant challenge lies in effectively analyzing the radiographs to decouple the intensity and phase information and accurately ascertain the density profile. Conventional algorithms often yield ambiguous and unrealistic results due to difficulties in including physical constraints and other relevant information. We have developed an algorithm that uses a deep neural network to address these issues and applied it to extract the detailed density profile from an experimental RER. To generalize the applicability of our algorithm, we have developed a technique that quantitatively evaluates the complexity of the phase retrieval process based on the characteristics of the sample and the configuration of the experiment. Accordingly, this evaluation aids in the selection of the neural network architecture for each specific case. Beyond RER, the model has potential applications for other diagnostics where phase retrieval analysis is required. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Development of a high performance MagLIF target platform using high aspect ratio coated liners and low-mix laser preheat.

Author

Harvey-Thompson, A. J., Geissel, M. E., Lewis, W. E., Yager-Elorriaga, D. A., Weis, M. R., Jennings, C. A., Fein, J. R., Ampleford, D. J., Gomez, M. R., Harding, E. C., Hansen, S. B., Bliss, D. E., Chandler, G. A., Dunham, G. S., Field, E. S., Galloway, B. R., Glinsky, M., Hahn, K. D., Knapp, P. F., and Lamppa, D. C.

Abstract

We report on a series of Magnetized Liner Inertial Fusion (MagLIF) experiments conducted on the Z pulsed power facility that utilized high aspect ratio (ratio of outer radius to wall thickness) liners with dielectric coatings and low-mix laser preheat configurations. The liners consisted of an aspect ratio of 10.6 beryllium tube coated with 75 μm of epoxy on the outside that have been shown to maintain a better implosion stability than uncoated beryllium and have demonstrated consistent stagnation performances in previous experiments [Ampleford et al., Phys. Plasmas 31, 022703 (2024)]. Two-dimensional HYDRA simulations were used to design three different "co-injection" laser configurations, whereby a second laser is used to provide an early prepulse before the main pulse, to reduce LEH foil mix while increasing the fuel density and coupled energy. The laser preheat energy for each configuration was constrained using dedicated laser experiments before being applied to the integrated MagLIF experiments on Z. The DD neutron yield for experiments using co-injection preheat configurations is found to increase with the specific preheat energy in line with simulations. The highest neutron yield achieved in this study of 1.1 × 1013 matches the highest reported in a MagLIF experiment to date and is a factor 3.5 times higher than similar experiments using preheat with no phase plate smoothing. We attempt to assess the effects of mix and morphology to explain the improved performance; however, neither factor is found to be conclusive within the uncertainty of the measurements. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Controlling morphology and improving reproducibility of magnetized liner inertial fusion experiments

Author

Ampleford, D. J., primary, Yager-Elorriaga, D. A., additional, Jennings, C. A., additional, Harding, E. C., additional, Gomez, M. R., additional, Harvey-Thompson, A. J., additional, Awe, T. J., additional, Chandler, G. A., additional, Dunham, G. S., additional, Geissel, M., additional, Hahn, K. D., additional, Hansen, S. B., additional, Knapp, P. F., additional, Lamppa, D. C., additional, Lewis, W. E., additional, Lucero, L., additional, Mangan, M., additional, Paguio, R., additional, Perea, L., additional, Robertson, G. A., additional, Ruiz, C. L., additional, Ruiz, D. E., additional, Schmit, P. F., additional, Slutz, S. A., additional, Smith, G. E., additional, Smith, I. C., additional, Speas, C. S., additional, Webb, T. J., additional, Weis, M. R., additional, Whittemore, K., additional, Yu, E. P., additional, McBride, R. D., additional, Peterson, K. J., additional, Jones, B. M., additional, Rochau, G. A., additional, and Sinars, D. B., additional

Published
2024
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13. Control and diagnosis of temperature, density, and uniformity in x-ray heated iron/magnesium samples for opacity measurements

Author

Nagayama, T., Bailey, J. E., Loisel, G., Hansen, S. B., Rochau, G. A., Mancini, R. C., MacFarlane, J. J., and Golovkin, I.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics
Abstract

Experimental tests are in progress to evaluate the accuracy of the modeled iron opacity at solar interior conditions, in particular to better constrain the solar abundance problem [S. Basu and H.M. Antia, Physics Reports 457, 217 (2008)]. Here we describe measurements addressing three of the key requirements for reliable opacity experiments: control of sample conditions, independent sample condition diagnostics, and verification of sample condition uniformity. The opacity samples consist of iron/magnesium layers tamped by plastic. By changing the plastic thicknesses, we have controlled the iron plasma conditions to reach i) Te=167+/-3 eV and ne=(7.1+/-1.5)e21 e/cc, ii) Te=170+/-2 eV and ne=(2.0+/-0.2)e22 e/cc, and iii) Te=196+/-6 eV and ne=(3.8+/-0.8)e22 e/cc, which were measured by magnesium tracer K-shell spectroscopy. The opacity sample non-uniformity was directly measured by a separate experiment where Al is mixed into the side of the sample facing the radiation source and Mg into the other side. The iron condition was confirmed to be uniform within their measurement uncertainties by Al and Mg K-shell spectroscopy. The conditions are suitable for testing opacity calculations needed for modeling the solar interior, other stars, and high energy density plasmas., Comment: Published online 14 May 2014

Published
2014
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14. Fast electron propagation in Ti foils irradiated with sub-picosecond laser pulses at $I\lambda^{2} > 10^{18}$ Wcm$^{-2} \mu m^{2}$

Author

Makita, M, Nersisyan, G, McKeever, K, Dzelzainis, T, White, S, Kettle, B, Dromey, B, Doria, D, Zepf, M, Lewis, CLS, Riley, D, Hansen, S. B., and Robinson, A. P. L.

Subjects
Physics - Plasma Physics
Abstract

We have studied the propagation of fast electrons through laser irradiated Ti foils by monitoring the emission of hard X-rays and K-{\alpha} radiation from bare foils and foils backed by a thick epoxy layer. Key observations include strong refluxing of electrons and divergence of the electron beam in the foil with evidence of magnetic field collimation. Our diagnostics have allowed us to estimate the fast electron temperature and fraction of laser energy converted to fast electrons. We have observed clear differences between the fast electron temperatures observed with bare and epoxy backed targets which may be due to the effects of refluxing.

Published
2014
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15. Generalized Collisional Radiative Model Using Screened Hydrogenic Levels

Author

Chung, H.-K., Hansen, S. B., Scott, H. A., Drake, Gordon W. F., Editor-in-chief, Babb, James, Series editor, Bandrauk, Andre D., Series editor, Bartschat, Klaus, Series editor, Burke, Philip George, Series editor, Compton, Robert N, Series editor, Gallagher, Tom, Series editor, Joachain, Charles J., Series editor, Lambropoulos, Peter, Series editor, Leuchs, Gerd, Series editor, Meystre, Pierre, Series editor, and Ralchenko, Yuri, editor

Published
2016
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17. Demonstration of improved laser preheat with a cryogenically cooled magnetized liner inertial fusion platform

Author

Harvey-Thompson, A. J., primary, Geissel, M., additional, Crabtree, J. A., additional, Weis, M. R., additional, Gomez, M. R., additional, Fein, J. R., additional, Lewis, W. E., additional, Ampleford, D. J., additional, Awe, T. J., additional, Chandler, G. A., additional, Galloway, B. R., additional, Hansen, S. B., additional, Hanson, J., additional, Harding, E. C., additional, Jennings, C. A., additional, Kimmel, M., additional, Knapp, P. F., additional, Mangan, M. A., additional, Maurer, A., additional, Paguio, R. R., additional, Perea, L., additional, Peterson, K. J., additional, Porter, J. L., additional, Rambo, P. K., additional, Robertson, G. K., additional, Rochau, G. A., additional, Ruiz, D. E., additional, Shores, J. E., additional, Slutz, S. A., additional, Smith, G. E., additional, Smith, I. C., additional, Speas, C. S., additional, Yager-Elorriaga, D. A., additional, and York, A., additional

Published
2023
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19. Experimental demonstration of >20 kJ laser energy coupling in 1-cm hydrocarbon-filled gas pipe targets via inverse Bremsstrahlung absorption with applications to MagLIF

Author

Pollock, B. B., primary, Goyon, C., additional, Sefkow, A. B., additional, Glinsky, M. E., additional, Peterson, K. J., additional, Weis, M. R., additional, Carroll, E. G., additional, Fry, J., additional, Piston, K., additional, Harvey-Thompson, A. J., additional, Hansen, S. B., additional, Beckwith, K., additional, Ampleford, D. J., additional, Tubman, E. R., additional, Strozzi, D. J., additional, Ross, J. S., additional, and Moody, J. D., additional

Published
2023
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20. Improving dynamic collision frequencies: Impacts on dynamic structure factors and stopping powers in warm dense matter

Author

Hentschel, T. W., Kononov, A., Olmstead, A., Cangi, A., Baczewski, A. D., and Hansen, S. B.

Subjects
Matter under extreme conditions, X-ray Thomson scattering, Average-atom models, Density functional theory, Time-dependent density functional theory, Collision frequencies, High-energy density science, Warm dense matter
Abstract

Simulations and diagnostics of high-energy-density plasmas and warm dense matter rely on models of material response properties, both static and dynamic (frequency-dependent). Here, we systematically investigate variations in dynamic electron–ion collision frequencies ν(ω) in warm dense matter using data from a self-consistent-field average-atom model. We show that including the full quantum density of states, strong collisions, and inelastic collisions lead to significant changes in ν(ω) ⁠. These changes result in red shifts and broadening of the plasmon peak in the dynamic structure factor, an effect observable in x-ray Thomson scattering spectra, and modify stopping powers around the Bragg peak. These changes improve the agreement of computationally efficient average-atom models with first-principles time-dependent density functional theory in warm dense aluminum, carbon, and deuterium.

Published
2023

22. Direct comparison of wire, foil, and hybrid X-pinches on a 200 kA, 150 ns current driver.

Author

Collins IV, G. W., Valdivia, M. P., Hansen, S. B., Conti, F., Carlson, L. C., Hammer, D. A., Elshafiey, A., Narkis, J., and Beg, F. N.

Subjects
COPPER wire, WIRE, SOFT X rays, ELECTRON beams
Abstract

Wire X-pinches (WXPs) have been studied comprehensively as fast (∼ 1 ns pulse width), small (∼ 1 μ m) x-ray sources, created by twisting two or more fine wires into an "X" to produce a localized region of extreme magnetic pressure at the cross-point. Recently, two alternatives to the traditional WXP have arisen: the hybrid X-pinch (HXP), composed of two conical electrodes bridged by a thin wire or capillary, and the laser-cut foil X-pinch (LCXP), cut from a thin foil using a laser. We present a comparison of copper wire, hybrid, and laser-cut foil X-pinches on a single experimental platform: UC San Diego's ∼ 200 kA, 150 ns rise time GenASIS driver. All configurations produced 1–2 ns pulse width, ≤ 5 μ m soft x-ray (Cu L-shell, ∼ 1 keV) sources (resolutions diagnostically limited) with comparable fluxes. WXP results varied with linear mass and wire count, but consistently showed separate pinch and electron-beam-driven sources. LCXPs produced the brightest (∼ 1 MW), smallest (≤ 5 μ m) Cu K-shell sources, and spectroscopic data showed both H-like Cu K α lines indicative of source temperatures ≥ 2 keV, and cold K α (∼ 8050 eV) characteristic of electron beam generated sources, which were not separately resolved on other diagnostics (within 1–2 ns and ≤ 200 μ m). HXPs produced minimal K-shell emission and reliably single, bright, and small L-shell sources after modifications to shape the early current pulse through them. Benefits and drawbacks for each configuration are discussed to provide potential X-pinch users with the information required to choose the configuration best suited to their needs. [ABSTRACT FROM AUTHOR]

Published
2021
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23. Self-consistent and detailed opacities from a non-equilibrium average-atom model.

Author

Hansen, S. B.

Subjects
*LOCAL thermodynamic equilibrium, *EQUATIONS of state, *ION recombination, *DENSITY functional theory, *PLASMA density, *TRP channels, *AUGER effect
Abstract

Modern density functional theory (DFT) is a powerful tool for accurately predicting self-consistent material properties such as equations of state, transport coefficients and opacities in high energy density plasmas, but it is generally restricted to conditions of local thermodynamic equilibrium (LTE) and produces only averaged electronic states instead of detailed configurations. We propose a simple modification to the bound-state occupation factor of a DFT-based average-atom model that captures essential non-LTE effects in plasmas—including autoionization and dielectronic recombination—thus extending DFT-based models to new regimes. We then expand the self-consistent electronic orbitals of the non-LTE DFT-AA model to generate multi-configuration electronic structure and detailed opacity spectra. This article is part of the theme issue 'Dynamic and transient processes in warm dense matter'. [ABSTRACT FROM AUTHOR]

Published
2023
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24. Homogeneous, Micron-Scale High-Energy-Density Matter Generated by Relativistic Laser-Solid Interactions

Author

Beier, N. F., primary, Allison, H., additional, Efthimion, P., additional, Flippo, K. A., additional, Gao, L., additional, Hansen, S. B., additional, Hill, K., additional, Hollinger, R., additional, Logantha, M., additional, Musthafa, Y., additional, Nedbailo, R., additional, Senthilkumaran, V., additional, Shepherd, R., additional, Shlyaptsev, V. N., additional, Song, H., additional, Wang, S., additional, Dollar, F., additional, Rocca, J. J., additional, and Hussein, A. E., additional

Published
2022
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25. First-principles derivation and properties of density-functional average-atom models

Author

(0000-0002-4878-3521) Callow, T. J., Hansen, S. B., (0000-0003-0139-258X) Kraisler, E., (0000-0001-9162-262X) Cangi, A., (0000-0002-4878-3521) Callow, T. J., Hansen, S. B., (0000-0003-0139-258X) Kraisler, E., and (0000-0001-9162-262X) Cangi, A.

Abstract

Finite-temperature Kohn--Sham density-functional theory (KS-DFT) is a widely-used method in warm dense matter (WDM) simulations and diagnostics. Unfortunately, full KS-DFT-molecular dynamics models scale unfavourably with temperature and there remains uncertainty regarding the performance of existing approximate exchange-correlation (XC) functionals under WDM conditions. Of particular concern is the expected explicit dependence of the XC functional on temperature, which is absent from most approximations. Average-atom (AA) models, which significantly reduce the computational cost of KS-DFT calculations, have therefore become an integral part of WDM modelling. In this paper, we present a derivation of a first-principles AA model from the fully-interacting many-body Hamiltonian, carefully analysing the assumptions made and terms neglected in this reduction. We explore the impact of different choices within this model -- such as boundary conditions and XC functionals -- on common properties in WDM, for example equation-of-state data, ionization degree and the behaviour of the frontier energy levels. Furthermore, drawing upon insights from ground-state KS-DFT, we discuss the likely sources of error in KS-AA models and possible strategies for mitigating such errors.

Published
2022

26. Improving Predictive Capability in REHEDS Simulations with Fast, Accurate, and Consistent Non-Equilibrium Material Properties

Author

Hansen, S. B., Baczewski, A. D., Gomez, T., Hentschel, T. W., Jennings, C. A., Kononov, A., Nagayama, T., Adler, K., (0000-0001-9162-262X) Cangi, A., Cochrane, K., Robinson, B., Schleife, A., Hansen, S. B., Baczewski, A. D., Gomez, T., Hentschel, T. W., Jennings, C. A., Kononov, A., Nagayama, T., Adler, K., (0000-0001-9162-262X) Cangi, A., Cochrane, K., Robinson, B., and Schleife, A.

Abstract

Predictive design of REHEDS experiments with radiation-hydrodynamic simulations requires knowledge of material properties (e.g. equations of state (EOS), transport coefficients, and radiation physics). Interpreting experimental results requires accurate models of diagnostic observables (e.g. detailed emission, absorption, and scattering spectra). In conditions of Local Thermodynamic Equilibrium (LTE), these material properties and observables can be pre-computed with relatively high accuracy and subsequently tabulated on simple temperature-density grids for fast look-up by simulations. When radiation and electron temperatures fall out of equilibrium, however, non-LTE effects can profoundly change material properties and diagnostic signatures. Accurately and efficiently incorporating these non-LTE effects has been a longstanding challenge for simulations. At present, most simulations include non-LTE effects by invoking highly simplified inline models. These inline non-LTE models are both much slower than table look-up and significantly less accurate than the detailed models used to populate LTE tables and diagnose experimental data through post-processing or inversion. Because inline non-LTE models are slow, designers avoid them whenever possible, which leads to known inaccuracies from using tabular LTE. Because inline models are simple, they are inconsistent with tabular data from detailed models, leading to ill-known inaccuracies, and they cannot generate detailed synthetic diagnostics suitable for direct comparisons with experimental data. This project addresses the challenge of generating and utilizing efficient, accurate, and consistent non-equilibrium material data along three complementary but relatively independent research lines. First, we have developed a relatively fast and accurate non-LTE average-atom model based on density functional theory (DFT) that provides a complete set of EOS, transport, and radiative data, and have rigorously tested it against mo

Published
2022

27. Data publication: First-principles derivation and properties of density-functional average-atom models

Author

(0000-0002-4878-3521) Callow, T. J., Hansen, S. B., (0000-0003-0139-258X) Kraisler, E., (0000-0001-9162-262X) Cangi, A., (0000-0002-4878-3521) Callow, T. J., Hansen, S. B., (0000-0003-0139-258X) Kraisler, E., and (0000-0001-9162-262X) Cangi, A.

Abstract

Data for the pre-print "First-principles derivation and properties of density-functional average-atom models", https://arxiv.org/abs/2103.09928. Each data folder is named according to the corresponding figure in the paper. For any questions, please contact the authors.

Published
2022

28. Estimation of stagnation performance metrics in magnetized liner inertial fusion experiments using Bayesian data assimilation

Author

Knapp, P. F., primary, Glinsky, M. E., additional, Schaeuble, M. A., additional, Jennings, C. A., additional, Evans, M., additional, Gunning, J., additional, Awe, T. J., additional, Chandler, G. A., additional, Geissel, M., additional, Gomez, M. R., additional, Hahn, K. D., additional, Hansen, S. B., additional, Harding, E. C., additional, Harvey-Thompson, A. J., additional, Humane, S., additional, Klein, B. T., additional, Mangan, M., additional, Nagayama, T., additional, Porwitzky, A. J., additional, Ruiz, D. E., additional, Schmit, P. F., additional, Slutz, S. A., additional, Smith, I. C., additional, Weis, M. R., additional, Yager-Elorriaga, D. A., additional, Ampleford, D. J., additional, Beckwith, K., additional, Mattsson, T. R., additional, Peterson, K. J., additional, and Sinars, D. B., additional

Published
2022
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34. Development on the National Ignition Facility of a High Energy Density Opacity Platform

Author

Perry, Theodore Sonne, primary, Dodd, Evan S., additional, DeVolder, Barbara Gloria, additional, Johns, Heather Marie, additional, Cardenas, Tana, additional, Archuleta, Thomas Nick, additional, Kline, John L., additional, Flippo, Kirk Adler, additional, Vinyard, Natalia Sergeevna, additional, Sherrill, Manolo Edgar, additional, Wilde, Bernhard Heinz, additional, Tregillis, Ian Lee, additional, Urbatsch, Todd James, additional, Douglas, Melissa Rae, additional, Heeter, R. F., additional, Liedahl, D. A., additional, Wilson, B. G., additional, Iglesias, C. A., additional, Schneider, M. B., additional, Martin, M. E., additional, London, R. A., additional, Ahmed, M. F., additional, Thompson, N. B., additional, Emig, J. A., additional, Zika, M. R., additional, Opachich, Y. P., additional, King, J. A., additional, Ross, P. W., additional, Huffman, E. J., additional, Knight, R. A., additional, Koch, J. A., additional, Pond, T. D., additional, Craxton, R. S., additional, Zhang, R., additional, McKenty, P. W., additional, Garcia, E. M., additional, Bailey, J. E., additional, Rochau, G. A., additional, and Hansen, S. B., additional

Published
2017
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35. Increased preheat energy to MagLIF targets with cryogenic cooling

Author

Harvey-Thompson, A. J., primary, Geissel, M., additional, Crabtree, J. A., additional, Weis, M. R., additional, Gomez, M. R., additional, Fein, J. R., additional, Ampleford, D. J., additional, Awe, T. J., additional, Chandler, G. A., additional, Galloway, B. R., additional, Hansen, S. B., additional, Hanson, J., additional, Harding, E. C., additional, Jennings, C. A., additional, Kimmel, M., additional, Knapp, P. F., additional, Lamppa, D. C., additional, Lewis, W. E., additional, Mangan, M. A., additional, Maurer, A., additional, Perea, L., additional, Peterson, K. J., additional, Porter, J. L., additional, Rambo, P. K., additional, Robertson, G. K., additional, Rochau, G. A., additional, Ruiz, D. E., additional, Shores, J. E., additional, Slutz, S. A., additional, Smith, I. C., additional, Speas, C. S., additional, Yager-Elorriaga, D. A., additional, York, A., additional, Paguio, R. R., additional, and Smith, G. E., additional

Published
2021
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36. First-principles derivation of an average-atom model from the many-body Hamiltonian of coupled electrons and ions

Author

Callow, T. J., Hansen, S. B., Kraisler, E., Gross, E., and Cangi, A.

Subjects
Physics::Atomic and Molecular Clusters, Physics::Chemical Physics
Abstract

In simulations of the warm dense matter regime, it is typical to use a combined finite-temperature Kohn-Sham density-functional theory (KS-DFT) and molecular dynamics approach. However, in KS-DFT, (i) scaling worsens with increasing temperature, and (ii) temperature dependence is usually neglected in the exchange-correlation (XC) functional. We present a derivation from first-principles which reduces the full many-body Hamiltonian to an average-atom model in the dilute gas limit, which significantly reduces the computational cost of the KS-DFT calculation. We also show preliminary results including a comparison of temperature-dependent and zero-temperature XC functionals.

Published
2021

37. First-principles derivation of an average-atom model from the many-body Hamiltonian of coupled electrons and ions

Author

(0000-0002-4878-3521) Callow, T. J., Hansen, S. B., (0000-0003-0139-258X) Kraisler, E., Gross, E., (0000-0001-9162-262X) Cangi, A., (0000-0002-4878-3521) Callow, T. J., Hansen, S. B., (0000-0003-0139-258X) Kraisler, E., Gross, E., and (0000-0001-9162-262X) Cangi, A.

Abstract

In simulations of the warm dense matter regime, it is typical to use a combined finite-temperature Kohn-Sham density-functional theory (KS-DFT) and molecular dynamics approach. However, in KS-DFT, (i) scaling worsens with increasing temperature, and (ii) temperature dependence is usually neglected in the exchange-correlation (XC) functional. We present a derivation from first-principles which reduces the full many-body Hamiltonian to an average-atom model in the dilute gas limit, which significantly reduces the computational cost of the KS-DFT calculation. We also show preliminary results including a comparison of temperature-dependent and zero-temperature XC functionals.

Published
2021

40. Eemian interglacial reconstructed from a Greenland folded ice core

Author

Dahl-Jensen, D., Albert, M. R., Aldahan, A., Azuma, N., Balslev-Clausen, D., Baumgartner, M., Berggren, A.-M., Bigler, M., Binder, T., Blunier, T., Bourgeois, J. C., Brook, E. J., Buchardt, S. L., Buizert, C., Capron, E., Chappellaz, J., Chung, J., Clausen, H. B., Cvijanovic, I., Davies, S. M., Ditlevsen, P., Eicher, O., Fischer, H., Fisher, D. A., Fleet, L. G., Gfeller, G., Gkinis, V., Gogineni, S., Goto-Azuma, K., Grinsted, A., Gudlaugsdottir, H., Guillevic, M., Hansen, S. B., Hansson, M., Hirabayashi, M., Hong, S., Hur, S. D., Huybrechts, P., Hvidberg, C. S., Iizuka, Y., Jenk, T., Johnsen, S. J., Jones, T. R., Jouzel, J., Karlsson, N. B., Kawamura, K., Keegan, K., Kettner, E., Kipfstuhl, S., Kjær, H. A., Koutnik, M., Kuramoto, T., Köhler, P., Laepple, T., Landais, A., Langen, P. L., Larsen, L. B., Leuenberger, D., Leuenberger, M., Leuschen, C., Li, J., Lipenkov, V., Martinerie, P., Maselli, O. J., Masson-Delmotte, V., McConnell, J. R., Miller, H., Mini, O., Miyamoto, A., Montagnat-Rentier, M., Mulvaney, R., Muscheler, R., Orsi, A. J., Paden, J., Panton, C., Pattyn, F., Petit, J.-R., Pol, K., Popp, T., Possnert, G., Prié, F., Prokopiou, M., Quiquet, A., Rasmussen, S. O., Raynaud, D., Ren, J., Reutenauer, C., Ritz, C., Röckmann, T., Rosen, J. L., Rubino, M., Rybak, O., Samyn, D., Sapart, C. J., Schilt, A., Schmidt, A. M. Z., Schwander, J., Schüpbach, S., Seierstad, I., Severinghaus, J. P., Sheldon, S., Simonsen, S. B., Sjolte, J., Solgaard, A. M., Sowers, T., Sperlich, P., Steen-Larsen, H. C., Steffen, K., Steffensen, J. P., Steinhage, D., Stocker, T. F., Stowasser, C., Sturevik, A. S., Sturges, W. T., Sveinbjörnsdottir, A., Svensson, A., Tison, J.-L., Uetake, J., Vallelonga, P., van de Wal, R. S. W., van der Wel, G., Vaughn, B. H., Vinther, B., Waddington, E., Wegner, A., Weikusat, I., White, J. W. C., Wilhelms, F., Winstrup, M., Witrant, E., Wolff, E. W., Xiao, C., and Zheng, J.

Published
2013
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42. Performance Scaling in Magnetized Liner Inertial Fusion Experiments

Author

Gomez, M. R., primary, Slutz, S. A., additional, Jennings, C. A., additional, Ampleford, D. J., additional, Weis, M. R., additional, Myers, C. E., additional, Yager-Elorriaga, D. A., additional, Hahn, K. D., additional, Hansen, S. B., additional, Harding, E. C., additional, Harvey-Thompson, A. J., additional, Lamppa, D. C., additional, Mangan, M., additional, Knapp, P. F., additional, Awe, T. J., additional, Chandler, G. A., additional, Cooper, G. W., additional, Fein, J. R., additional, Geissel, M., additional, Glinsky, M. E., additional, Lewis, W. E., additional, Ruiz, C. L., additional, Ruiz, D. E., additional, Savage, M. E., additional, Schmit, P. F., additional, Smith, I. C., additional, Styron, J. D., additional, Porter, J. L., additional, Jones, B., additional, Mattsson, T. R., additional, Peterson, K. J., additional, Rochau, G. A., additional, and Sinars, D. B., additional

Published
2020
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44. Review of pulsed power-driven high energy density physics research on Z at Sandia

Author

Sinars, D. B., primary, Sweeney, M. A., additional, Alexander, C. S., additional, Ampleford, D. J., additional, Ao, T., additional, Apruzese, J. P., additional, Aragon, C., additional, Armstrong, D. J., additional, Austin, K. N., additional, Awe, T. J., additional, Baczewski, A. D., additional, Bailey, J. E., additional, Baker, K. L., additional, Ball, C. R., additional, Barclay, H. T., additional, Beatty, S., additional, Beckwith, K., additional, Bell, K. S., additional, Benage, J. F., additional, Bennett, N. L., additional, Blaha, K., additional, Bliss, D. E., additional, Boerner, J. J., additional, Bourdon, C. J., additional, Branch, B. A., additional, Brown, J. L., additional, Campbell, E. M., additional, Campbell, R. B., additional, Chacon, D. G., additional, Chandler, G. A., additional, Chandler, K., additional, Christenson, P. J., additional, Christison, M. D., additional, Christner, E. B., additional, Clay, R. C., additional, Cochrane, K. R., additional, Colombo, A. P., additional, Cook, B. M., additional, Coverdale, C. A., additional, Cuneo, M. E., additional, Custer, J. S., additional, Dasgupta, A., additional, Davis, J.-P., additional, Desjarlais, M. P., additional, Dolan, D. H., additional, Douglass, J. D., additional, Dunham, G. S., additional, Duwal, S., additional, Edens, A. D., additional, Edwards, M. J., additional, Evstatiev, E. G., additional, Farfan, B. G., additional, Fein, J. R., additional, Field, E. S., additional, Fisher, J. A., additional, Flanagan, T. M., additional, Flicker, D. G., additional, Furnish, M. D., additional, Galloway, B. R., additional, Gard, P. D., additional, Gardiner, T. A., additional, Geissel, M., additional, Giuliani, J. L., additional, Glinsky, M. E., additional, Gomez, M. R., additional, Gomez, T., additional, Grim, G. P., additional, Hahn, K. D., additional, Haill, T. A., additional, Hamlin, N. D., additional, Hammer, J. H., additional, Hansen, S. B., additional, Hanshaw, H. L., additional, Harding, E. C., additional, Harvey-Thompson, A. J., additional, Headley, D., additional, Herrmann, M. C., additional, Hess, M. H., additional, Highstrete, C., additional, Hurricane, O. A., additional, Hutsel, B. T., additional, Jennings, C. A., additional, Johns, O. M., additional, Johnson, D., additional, Johnston, M. D., additional, Jones, B. M., additional, Jones, M. C., additional, Jones, P. A., additional, Kalita, P. E., additional, Kamm, R. J., additional, Kellogg, J. W., additional, Kiefer, M. L., additional, Kimmel, M. W., additional, Knapp, P. F., additional, Knudson, M. D., additional, Kreft, A., additional, Laity, G. R., additional, Lake, P. W., additional, Lamppa, D. C., additional, Langston, W. L., additional, Lash, J. S., additional, LeChien, K. R., additional, Leckbee, J. J., additional, Leeper, R. J., additional, Leifeste, G. T., additional, Lemke, R. W., additional, Lewis, W., additional, Lewis, S. A., additional, Loisel, G. P., additional, Looker, Q. M., additional, Lopez, A. J., additional, Lucero, D. J., additional, MacLaren, S. A., additional, Magyar, R. J., additional, Mangan, M. A., additional, Martin, M. R., additional, Mattsson, T. R., additional, Matzen, M. K., additional, Maurer, A. J., additional, Mazarakis, M. G., additional, McBride, R. D., additional, McLean, H. S., additional, McCoy, C. A., additional, McKee, G. R., additional, McKenney, J. L., additional, Miles, A. R., additional, Mills, J. A., additional, Mitchell, M. D., additional, Moore, N. W., additional, Myers, C. E., additional, Nagayama, T., additional, Natoni, G., additional, Owen, A. C., additional, Patel, S., additional, Peterson, K. J., additional, Pointon, T. D., additional, Porter, J. L., additional, Porwitzky, A. J., additional, Radovich, S., additional, Raman, K. S., additional, Rambo, P. K., additional, Reinhart, W. D., additional, Robertson, G. K., additional, Rochau, G. A., additional, Root, S., additional, Rose, D. V., additional, Rovang, D. C., additional, Ruiz, C. L., additional, Ruiz, D. E., additional, Sandoval, D., additional, Savage, M. E., additional, Sceiford, M. E., additional, Schaeuble, M. A., additional, Schmit, P. F., additional, Schollmeier, M. S., additional, Schwarz, J., additional, Seagle, C. T., additional, Sefkow, A. B., additional, Seidel, D. B., additional, Shipley, G. A., additional, Shores, J., additional, Shulenburger, L., additional, Simpson, S. C., additional, Slutz, S. A., additional, Smith, I. C., additional, Speas, C. S., additional, Specht, P. E., additional, Speir, M. J., additional, Spencer, D. C., additional, Springer, P. T., additional, Steiner, A. M., additional, Stoltzfus, B. S., additional, Stygar, W. A., additional, Ward Thornhill, J., additional, Torres, J. A., additional, Townsend, J. P., additional, Tyler, C., additional, Vesey, R. A., additional, Wakeland, P. E., additional, Webb, T. J., additional, Weinbrecht, E. A., additional, Weis, M. R., additional, Welch, D. R., additional, Wise, J. L., additional, Wu, M., additional, Yager-Elorriaga, D. A., additional, Yu, A., additional, and Yu, E. P., additional

Published
2020
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45. Magnetic field impact on the laser heating in MagLIF

Author

Carpenter, K. R., primary, Mancini, R. C., additional, Harding, E. C., additional, Harvey-Thompson, A. J., additional, Geissel, M., additional, Weis, M. R., additional, Hansen, S. B., additional, Peterson, K. J., additional, and Rochau, G. A., additional

Published
2020
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