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TAFI/Kebab End of Project Report

Rintoul, Mark D.; Wisniewski, Kyra L.; Ward, Katrina J.; Khanna, Kanad K.

This report focuses on the two primary goals set forth in Sandia’s TAFI effort, referred to here under the name Kebab. The first goal is to overlay a trajectory onto a large database of historical trajectories, all with very different sampling rates than the original track. We demonstrate a fast method to accomplish this, even for databases that hold over a million tracks. The second goal is to then demonstrate that these matched historical trajectories can be used to make predictions about unknown qualities associated with the original trajectory. As part of this work, we also examine the problem of defining the qualities of a trajectory in a reproducible way.

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TYPE Other Report YEAR 2021
OSTIDOI

Efficacy of the radial pair potential approximation for molecular dynamics simulations of dense plasmas

Physics of Plasmas

Stanek, Lucas J.; Clay III, Raymond C.; Dharma-Wardana, M.W.C.; Wood, Mitchell A.; Beckwith, Kristian B.; Murillo, Michael S.

Macroscopic simulations of dense plasmas rely on detailed microscopic information that can be computationally expensive and is difficult to verify experimentally. In this work, we delineate the accuracy boundary between microscale simulation methods by comparing Kohn-Sham density functional theory molecular dynamics (KS-MD) and radial pair potential molecular dynamics (RPP-MD) for a range of elements, temperature, and density. By extracting the optimal RPP from KS-MD data using force matching, we constrain its functional form and dismiss classes of potentials that assume a constant power law for small interparticle distances. Our results show excellent agreement between RPP-MD and KS-MD for multiple metrics of accuracy at temperatures of only a few electron volts. The use of RPPs offers orders of magnitude decrease in computational cost and indicates that three-body potentials are not required beyond temperatures of a few eV. Due to its efficiency, the validated RPP-MD provides an avenue for reducing errors due to finite-size effects that can be on the order of ∼ 20 %.

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TYPE Journal Article YEAR 2021
ScopusOSTIDOI
Results 826–850 of 9,998
Results 826–850 of 9,998