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Title: Multiscale Molecular Dynamics Model for Heterogeneous Charged Systems

Abstract

Here, modeling matter across large length scales and timescales using molecular dynamics simulations poses significant challenges. These challenges are typically addressed through the use of precomputed pair potentials that depend on thermodynamic properties like temperature and density; however, many scenarios of interest involve spatiotemporal variations in these properties, and such variations can violate assumptions made in constructing these potentials, thus precluding their use. In particular, when a system is strongly heterogeneous, most of the usual simplifying assumptions (e.g., spherical potentials) do not apply. Here, we present a multiscale approach to orbital-free density functional theory molecular dynamics (OFDFT-MD) simulations that bridges atomic, interionic, and continuum length scales to allow for variations in hydrodynamic quantities in a consistent way. Our multiscale approach enables simulations on the order of micron length scales and 10’s of picosecond timescales, which exceeds current OFDFT-MD simulations by many orders of magnitude. This new capability is then used to study the heterogeneous, nonequilibrium dynamics of a heated interface characteristic of an inertial-confinement-fusion capsule containing a plastic ablator near a fuel layer composed of deuterium-tritium ice. At these scales, fundamental assumptions of continuum models are explored; features such as the separation of the momentum fields among the species andmore » strong hydrogen jetting from the plastic into the fuel region are observed, which had previously not been seen in hydrodynamic simulations.« less

Authors:
 [1];  [1];  [2]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Michigan State Univ., East Lansing, MI (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1437338
Alternate Identifier(s):
OSTI ID: 1463020
Report Number(s):
LLNL-JRNL-732633
Journal ID: ISSN 2160-3308; PRXHAE; 884106
Grant/Contract Number:  
AC52-07NA27344; AC52-06NA25396
Resource Type:
Journal Article: Published Article
Journal Name:
Physical Review. X
Additional Journal Information:
Journal Volume: 8; Journal Issue: 2; Journal ID: ISSN 2160-3308
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English
Subject:
97 MATHEMATICS AND COMPUTING; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Stanton, L. G., Glosli, J. N., and Murillo, M. S.. Multiscale Molecular Dynamics Model for Heterogeneous Charged Systems. United States: N. p., 2018. Web. doi:10.1103/PhysRevX.8.021044.
Stanton, L. G., Glosli, J. N., & Murillo, M. S.. Multiscale Molecular Dynamics Model for Heterogeneous Charged Systems. United States. doi:10.1103/PhysRevX.8.021044.
Stanton, L. G., Glosli, J. N., and Murillo, M. S.. Wed . "Multiscale Molecular Dynamics Model for Heterogeneous Charged Systems". United States. doi:10.1103/PhysRevX.8.021044.
@article{osti_1437338,
title = {Multiscale Molecular Dynamics Model for Heterogeneous Charged Systems},
author = {Stanton, L. G. and Glosli, J. N. and Murillo, M. S.},
abstractNote = {Here, modeling matter across large length scales and timescales using molecular dynamics simulations poses significant challenges. These challenges are typically addressed through the use of precomputed pair potentials that depend on thermodynamic properties like temperature and density; however, many scenarios of interest involve spatiotemporal variations in these properties, and such variations can violate assumptions made in constructing these potentials, thus precluding their use. In particular, when a system is strongly heterogeneous, most of the usual simplifying assumptions (e.g., spherical potentials) do not apply. Here, we present a multiscale approach to orbital-free density functional theory molecular dynamics (OFDFT-MD) simulations that bridges atomic, interionic, and continuum length scales to allow for variations in hydrodynamic quantities in a consistent way. Our multiscale approach enables simulations on the order of micron length scales and 10’s of picosecond timescales, which exceeds current OFDFT-MD simulations by many orders of magnitude. This new capability is then used to study the heterogeneous, nonequilibrium dynamics of a heated interface characteristic of an inertial-confinement-fusion capsule containing a plastic ablator near a fuel layer composed of deuterium-tritium ice. At these scales, fundamental assumptions of continuum models are explored; features such as the separation of the momentum fields among the species and strong hydrogen jetting from the plastic into the fuel region are observed, which had previously not been seen in hydrodynamic simulations.},
doi = {10.1103/PhysRevX.8.021044},
journal = {Physical Review. X},
number = 2,
volume = 8,
place = {United States},
year = {Wed May 16 00:00:00 EDT 2018},
month = {Wed May 16 00:00:00 EDT 2018}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevX.8.021044

Citation Metrics:
Cited by: 1 work
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