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High accuracy Hugoniot measurements at multi-megabar pressure utilizing the Sandia Z accelerator

Journal of Physics: Conference Series

Alexander, Charles S.; Knudson, Marcus D.; Hall, Clint A.

The Hugoniot response of materials is centrally important in the field of high pressure science. Highly accurate Hugoniot measurements not only provide better material references but also allow for the detection of subtle material phenomena. A process has been developed utilizing the Sandia Z accelerator to measure Hugoniot response at multi-megabar pressure resulting in extremely high accuracy data. Key considerations are the use of large surface area flyer plates allowing measurement configurations with multiple targets and diagnostics. This allows for greatly reduced uncertainty in the data. The details of this process are given and each aspect is closely examined focusing on the individual contributions to the overall accuracy of the result. © 2010 IOP Publishing Ltd.

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TYPE Conference YEAR 2010
ScopusOSTI

Equation of state and transport property measurements of warm dense matter

Knudson, Marcus D.; Desjarlais, Michael P.

Location of the liquid-vapor critical point (c.p.) is one of the key features of equation of state models used in simulating high energy density physics and pulsed power experiments. For example, material behavior in the location of the vapor dome is critical in determining how and when coronal plasmas form in expanding wires. Transport properties, such as conductivity and opacity, can vary an order of magnitude depending on whether the state of the material is inside or outside of the vapor dome. Due to the difficulty in experimentally producing states near the vapor dome, for all but a few materials, such as Cesium and Mercury, the uncertainty in the location of the c.p. is of order 100%. These states of interest can be produced on Z through high-velocity shock and release experiments. For example, it is estimated that release adiabats from {approx}1000 GPa in aluminum would skirt the vapor dome allowing estimates of the c.p. to be made. This is within the reach of Z experiments (flyer plate velocity of {approx}30 km/s). Recent high-fidelity EOS models and hydrocode simulations suggest that the dynamic two-phase flow behavior observed in initial scoping experiments can be reproduced, providing a link between theory and experiment. Experimental identification of the c.p. in aluminum would represent the first measurement of its kind in a dynamic experiment. Furthermore, once the c.p. has been experimentally determined it should be possible to probe the electrical conductivity, opacity, reflectivity, etc. of the material near the vapor dome, using a variety of diagnostics. We propose a combined experimental and theoretical investigation with the initial emphasis on aluminum.

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TYPE SAND Report YEAR 2009
OSTIDOI

Towards a predictive MHD simulation capability for designing hypervelocity magnetically-driven flyer plates and PWclass z-pinch x-ray sources on Z and ZR

Mehlhorn, Thomas A.; Yu, Edmund Y.; Vesey, Roger A.; Cuneo, M.E.; Jones, Brent M.; Knudson, Marcus D.; Sinars, Daniel S.; Robinson, Allen C.; Trucano, Timothy G.; Brunner, Thomas A.; Desjarlais, Michael P.; Garasi, Christopher J.; Haill, Thomas A.; Hanshaw, Heath L.; Lemke, Raymond W.; Oliver, Bryan V.; Peterson, Kyle J.

Abstract not provided.

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TYPE Conference YEAR 2007
OSTI
Results 101–125 of 155
Results 101–125 of 155