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Title: First-principles investigations on ionization and thermal conductivity of polystyrene for inertial confinement fusion applications

Abstract

Using quantum molecular-dynamics (QMD) methods based on the density functional theory, we have performed first-principles investigations of the ionization and thermal conductivity of polystyrene (CH) over a wide range of plasma conditions (ρ = 0.5 to 100 g/cm{sup 3} and T = 15 625 to 500 000 K). The ionization data from orbital-free molecular-dynamics calculations have been fitted with a “Saha-type” model as a function of the CH plasma density and temperature, which gives an increasing ionization as the CH density increases even at low temperatures (T < 50 eV). The orbital-free molecular dynamics method is only used to gauge the average ionization behavior of CH under the average-atom model in conjunction with the pressure-matching mixing rule. The thermal conductivities (κ{sub QMD}) of CH, derived directly from the Kohn–Sham molecular-dynamics calculations, are then analytically fitted with a generalized Coulomb logarithm [(lnΛ){sub QMD}] over a wide range of plasma conditions. When compared with the traditional ionization and thermal conductivity models used in radiation–hydrodynamics codes for inertial confinement fusion simulations, the QMD results show a large difference in the low-temperature regime in which strong coupling and electron degeneracy play an essential role in determining plasma properties. Hydrodynamic simulations of cryogenic deuterium–tritium targets with CH ablators on OMEGA and the National Ignitionmore » Facility using the QMD-derived ionization and thermal conductivity of CH have predicted ∼20% variation in target performance in terms of hot-spot pressure and neutron yield (gain) with respect to traditional model simulations.« less

Authors:
; ;  [1]; ;  [2]
  1. Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States)
  2. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
Publication Date:
OSTI Identifier:
22599138
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 4; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; DENSITY; DENSITY FUNCTIONAL METHOD; DEUTERIUM TARGET; ELECTRONS; HYDRODYNAMIC MODEL; HYDRODYNAMICS; INERTIAL CONFINEMENT; IONIZATION; MOLECULAR DYNAMICS METHOD; NEUTRONS; PLASMA DENSITY; POLYSTYRENE; STRONG-COUPLING MODEL; T-15 TOKAMAK; TEMPERATURE RANGE 0065-0273 K; THERMAL CONDUCTIVITY; THERMONUCLEAR IGNITION; TRITIUM TARGET

Citation Formats

Hu, S. X., E-mail: shu@lle.rochester.edu, Goncharov, V. N., McCrory, R. L., Skupsky, S., Collins, L. A., and Kress, J. D. First-principles investigations on ionization and thermal conductivity of polystyrene for inertial confinement fusion applications. United States: N. p., 2016. Web. doi:10.1063/1.4945753.
Hu, S. X., E-mail: shu@lle.rochester.edu, Goncharov, V. N., McCrory, R. L., Skupsky, S., Collins, L. A., & Kress, J. D. First-principles investigations on ionization and thermal conductivity of polystyrene for inertial confinement fusion applications. United States. doi:10.1063/1.4945753.
Hu, S. X., E-mail: shu@lle.rochester.edu, Goncharov, V. N., McCrory, R. L., Skupsky, S., Collins, L. A., and Kress, J. D. Fri . "First-principles investigations on ionization and thermal conductivity of polystyrene for inertial confinement fusion applications". United States. doi:10.1063/1.4945753.
@article{osti_22599138,
title = {First-principles investigations on ionization and thermal conductivity of polystyrene for inertial confinement fusion applications},
author = {Hu, S. X., E-mail: shu@lle.rochester.edu and Goncharov, V. N. and McCrory, R. L. and Skupsky, S. and Collins, L. A. and Kress, J. D.},
abstractNote = {Using quantum molecular-dynamics (QMD) methods based on the density functional theory, we have performed first-principles investigations of the ionization and thermal conductivity of polystyrene (CH) over a wide range of plasma conditions (ρ = 0.5 to 100 g/cm{sup 3} and T = 15 625 to 500 000 K). The ionization data from orbital-free molecular-dynamics calculations have been fitted with a “Saha-type” model as a function of the CH plasma density and temperature, which gives an increasing ionization as the CH density increases even at low temperatures (T < 50 eV). The orbital-free molecular dynamics method is only used to gauge the average ionization behavior of CH under the average-atom model in conjunction with the pressure-matching mixing rule. The thermal conductivities (κ{sub QMD}) of CH, derived directly from the Kohn–Sham molecular-dynamics calculations, are then analytically fitted with a generalized Coulomb logarithm [(lnΛ){sub QMD}] over a wide range of plasma conditions. When compared with the traditional ionization and thermal conductivity models used in radiation–hydrodynamics codes for inertial confinement fusion simulations, the QMD results show a large difference in the low-temperature regime in which strong coupling and electron degeneracy play an essential role in determining plasma properties. Hydrodynamic simulations of cryogenic deuterium–tritium targets with CH ablators on OMEGA and the National Ignition Facility using the QMD-derived ionization and thermal conductivity of CH have predicted ∼20% variation in target performance in terms of hot-spot pressure and neutron yield (gain) with respect to traditional model simulations.},
doi = {10.1063/1.4945753},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 4,
volume = 23,
place = {United States},
year = {2016},
month = {4}
}

Works referencing / citing this record:

High Pressure Hydrocarbons Revisited: From van der Waals Compounds to Diamond
journal, May 2019


High Pressure Hydrocarbons Revisited: From van der Waals Compounds to Diamond
journal, May 2019