## Dynamic Materials Topics

Shock-Wave Exploration of the High-Pressure Phases of Carbon *(MD Knudson, MP Desjarlais, DH Dolan) Science 322, 1822 (2008)* The high-energy density behavior of carbon, particularly in the vicinity of the melt boundary, is of broad scientific interest and of particular interest to those studying planetary astrophysics and inertial confinement fusion.

Probing off-Hugoniot sttes in Ta, Cu, and AI to 1000GPa compression with magnetically driven liner implosions *(RW Lemke, DH Dolan, DG Dalton, et al.), Journal of Applied Physics, 119, 015904* (2016) Exploring cylindrical convergence, the Sandia team of scientists compressed metals to 1000 GPa/10 Mbar using Sandia’s Z machine. The paper describes the experimental method and the theoretical approach to infer equation of state information from the experiment.

Quantum Monte Carlo applied to solids *(L Shulenburger, TR Mattsson) Physical Review B 88, 245117 (2013) *Quantum Monte Carlo (QMC) is a high-accuracy method for performing calculations of properties of materials. This article presents first-ever benchmark calculations of the performance of QMC for solids by doing calculations for a broad set of different solids with different bonding (ionic, metallic, semiconducting, and van-der Waals).

Shock Compression of a Fifth Period Element: Liquid Xenon to 840 GPa *(S Root, RJ Magyar, JH Carpenter, DL Hanson, TR Mattsson) Physical Review Letters 105, 085501 (2010) *Sandia scientists increased the range of pressure where the behavior of xenon is known almost ten-fold, making high-precision measurements of shock compression of liquid xenon to 8 million atmospheres. In addition to the groundbreaking experiments, the team employed simulations based on quantum mechanics to predict the behavior – strongly validating the use of density functional theory (DFT) in the area of shock physics.

On the scaling of the magnetically accelerated flyer plate technique to currents greater than 20 MA *(RW Lemke, MD Knudson, KR Cochrane, MP Desjarlais, JR Asay) Journal of Physics: Conference Series, Volume 500, Part 15 (2014) *The use of magnetically accelerated flyer plates revolutionized the field of shock physics 15 years ago in that it was suddenly possible to perform high-precision experiments at multi-Mbar pressures. This article presents the underlying theory of the method and how performance scales with increase in drive current.

Shock Compression of Quartz to 1.6 TPa: Redefining a Pressure Standard *(MD Knudson, MP Desjarlais) Physical Review Letters 103, 225501 (2009) *Quartz is widely used as a standard for shock experiments – the paper presents very high precision data and first-principles simulations determining the properties of quartz (SiO2) to 16 Mbar, or 16 million atmospheres pressure.

* *Analysis of shockless dynamic compression data on solids to multi-megabar pressures: Application to tantalum *(J-P Davis, JL Brown, MD Knudson, RW Lemke) Journal of Applied Physics 116, 204903 (2014) *Sandia scientists developed an approach to producing shockless compressions on high Z materials to stresses greater than 300 GPa. The paper describes the experimental method and the theoretical approach to infer equation of state information from the experiment.

Flow strength of tantalum under ramp compression to 250 GPa *(JL Brown, CS Alexander, JR Asay, TJ Vogler, DH Dolan, JL Belof) Journal of Applied Physics 115, 043530 (2014) *Novel experiments are described where a ramp compression and release technique is applied to materials on the Z machine to measure material strength. Data is presented for measurements on tantalum up to pressures of 250 Gpa.