An Overview of Pulse Compression and Power Flow in the Upgraded Z Pulsed Power Driver

Savage, M. E.; Bennett, L.F.; Bliss, David E.; Clark, W.T.; Coats, R. S.; Elizondo, J.M.; LeChien, K. R.; Harjes, H.C.; Lehr, J.M.; Maenchen, J.E.; McDaniel, D. H.; Pasik, Michael F.; Pointon, T.D.; Owen, A.; Seidel, D. B.; Smith, David L.; Stoltzfus, Brian; Struve, K. W.; Stygar, W. A.; Warne, Larry K.; Woodworth, J. R.; Mendel, C. W.; Prestwich, K.R.; Shoup, R.W.; Johnson, D.L.; Corley, J.P.; Hodge, K.C.; Wagoner, T. C.; Wakeland, P.

doi:10.1109/ppps.2007.4345943

Cited by 23 publications

(12 citation statements)

References 18 publications

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“…We conducted a series of shock compression experiments to measure the Hugoniot using Sandia's Z Machine. The Z Machine is a pulsed power source capable of delivering ∼20 MA current pulses over a few 100 ns to a target (Matzen, ; Savage et al, ; Spielman et al, ). The large current produces a strong magnetic field, and the combined current and magnetic field generate a Lorentz force, F = J × B , capable of accelerating an aluminum flyer plate up to 40 km/s.…”

Section: Methodsmentioning

confidence: 99%

The Principal Hugoniot of Forsterite to 950 GPa

Root

Townsend

Davies

et al. 2018

Geophysical Research Letters

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Forsterite (Mg 2 SiO 4 ) single crystals were shock compressed to pressures between 200 and 950 GPa using independent plate-impact steady shocks and laser-driven decaying shock compression experiments. Additionally, we performed density functional theory-based molecular dynamics to aid interpretation of the experimental data and to investigate possible phase transformations and phase separations along the Hugoniot. We show that the experimentally obtained Hugoniot cannot distinguish between a pure liquid Mg 2 SiO 4 and an assemblage of solid MgO plus liquid magnesium silicate. The measured reflectivity is nonzero and increases with pressure, which implies that the liquid is a poor electrical conductor at low pressures and that the conductivity increases with pressure.Plain Language Summary Hypervelocity impacts are an important process for planetary and moon formation and evolution. These impact events generate pressures of millions of atmospheres. Forsterite (Mg 2 SiO 4 ) is the magnesium end-member of the olivine series and is a major constituent of the Earth's mantle and likely other terrestrial planets including the recently discovered super-Earths. Here we used Sandia National Laboratories Z Machine and the OMEGA Laser Facility at the University of Rochester to shock compress forsterite to extreme pressures and temperatures. The experiments provide data showing the relationship between pressure, density, and temperature that can be used to construct a model of forsterite's behavior at extreme conditions. Improved knowledge of the properties of forsterite at the extreme pressures created in impacts or in the interiors of super-Earths will help us better understand the formation and interior structure of moons and planets.

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Section: Methodsmentioning

confidence: 99%

The Principal Hugoniot of Forsterite to 950 GPa

Root

Townsend

Davies

et al. 2018

Geophysical Research Letters

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“…1. Briefly, the experiments were conducted using Sandia National Laboratories's Z-machine (Savage et al, 2007), which is a pulsed power driver that can deliver massive electrical currents (of the order of 20 MA) over very short timescales (of the order of 1 μs). These currents were forced to flow along an aluminium (Al) panel, producing a large magnetic pressure which drives a time-dependent stress wave (impulse) into the system.…”

Section: Experimental Configuration and Modellingmentioning

confidence: 99%

Estimating Material Properties Under Extreme Conditions by Using Bayesian Model Calibration with Functional Outputs

Brown

Hund

2018

Journal of the Royal Statistical Society Series C: Applied Statistics

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Summary Dynamic material properties experiments provide access to the most extreme temperatures and pressures attainable in a laboratory setting; the data from these experiments are often used to improve our understanding of material models at these extreme conditions. We apply Bayesian model calibration to dynamic material property applications where the experimental output is a function: velocity over time. This framework can accommodate more uncertainties and facilitate analysis of new types of experiments relative to techniques traditionally used to analyse dynamic material experiments. However, implementation of Bayesian model calibration requires more sophisticated statistical techniques, because of the functional nature of the output as well as parameter and model discrepancy identifiability. We propose a novel Bayesian model calibration process to simplify and improve the estimation of the material property calibration parameters. Specifically, we propose scaling the likelihood function by an effective sample size rather than modelling the auto‐correlation function to accommodate the functional output. Additionally, we propose sensitivity analyses by using the notion of 'modularization' to assess the effect of experiment‐specific nuisance input parameters on estimates of the physical parameters. The Bayesian model calibration framework proposed is applied to dynamic compression of tantalum to extreme pressures, and we conclude that the procedure results in simple, fast and valid inferences on the material properties for tantalum.

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“…The high-precision data constrain the Hugoniot at multi-Mbar pressures, and the DFT and QMC results further elucidate information on the phase boundaries. This work provides accurate EOS data at extreme conditions and furthermore reveals lower limits of the relative velocity required in the giant impact scenario for moon formation.To attain planetary impact conditions, we performed a series of shock compression experiments using the Sandia Z-Machine [27]. The Z-machine is a pulsed power system capable of producing shaped current pulses and induced magnetic fields in excess of 20 MA and 10 MG respectively.…”

mentioning

confidence: 99%

“…To attain planetary impact conditions, we performed a series of shock compression experiments using the Sandia Z-Machine [27]. The Z-machine is a pulsed power system capable of producing shaped current pulses and induced magnetic fields in excess of 20 MA and 10 MG respectively.…”

mentioning

confidence: 99%

Shock Response and Phase Transitions of MgO at Planetary Impact Conditions

et al. 2015

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The moon-forming impact and the subsequent evolution of the proto-Earth is strongly dependent on the properties of materials at the extreme conditions generated by this violent collision. We examine the high pressure behavior of MgO, one of the dominant constituents in Earth's mantle, using high-precision, plate impact shock compression experiments performed on Sandia National Laboratories' Z Machine and extensive quantum calculations using density functional theory (DFT) and quantum Monte Carlo (QMC) methods. The combined data span from ambient conditions to 1.2 TPa and 42 000 K, showing solid-solid and solid-liquid phase boundaries. Furthermore our results indicate that under impact the solid and liquid phases coexist for more than 100 GPa, pushing complete melting to pressures in excess of 600 GPa. The high pressure required for complete shock melting has implications for a broad range of planetary collision events.

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An Overview of Pulse Compression and Power Flow in the Upgraded Z Pulsed Power Driver

Cited by 23 publications

References 18 publications

The Principal Hugoniot of Forsterite to 950 GPa

The Principal Hugoniot of Forsterite to 950 GPa

Estimating Material Properties Under Extreme Conditions by Using Bayesian Model Calibration with Functional Outputs

Shock Response and Phase Transitions of MgO at Planetary Impact Conditions

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