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Title: Testing nonlocal models of electron thermal conduction for magnetic and inertial confinement fusion applications

Abstract

Three models for nonlocal electron thermal transport are here compared against Vlasov-Fokker-Planck (VFP) codes to assess their accuracy in situations relevant to both inertial fusion hohlraums and tokamak scrape-off layers. The models tested are (i) a moment-based approach using an eigenvector integral closure (EIC) originally developed by Ji, Held, and Sovinec [Phys. Plasmas 16, 022312 (2009)]; (ii) the non-Fourier Landau-fluid (NFLF) model of Dimits, Joseph, and Umansky [Phys. Plasmas 21, 055907 (2014)]; and (iii) Schurtz, Nicolaï, and Busquet’s [Phys. Plasmas 7, 4238 (2000)] multigroup diffusion model (SNB). We find that while the EIC and NFLF models accurately predict the damping rate of a small-amplitude temperature perturbation (within 10% at moderate collisionalities), they overestimate the peak heat flow by as much as 35% and do not predict preheat in the more relevant case where there is a large temperature difference. The SNB model, however, agrees better with VFP results for the latter problem if care is taken with the definition of the mean free path. Additionally, we present for the first time a comparison of the SNB model against a VFP code for a hohlraum-relevant problem with inhomogeneous ionisation and show that the model overestimates the heat flow in the heliummore » gas-fill by a factor of ~2 despite predicting the peak heat flux to within 16%.« less

Authors:
ORCiD logo [1];  [2];  [3]; ORCiD logo [3];  [4]; ORCiD logo [5];  [3]; ORCiD logo [1]; ORCiD logo [1];  [6];  [3];  [3];  [1]
  1. Univ. of York (United Kingdom). Department of Physics, York Plasma Institute
  2. Imperial College, London (United Kingdom). Plasma Physics Group, Blackett Laboratory
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  4. Max-Planck-Institute for Plasma Physics (Germany)
  5. Chalmers University of Technology (Sweden). Department of Physics
  6. Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab. (RAL)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1393324
Alternate Identifier(s):
OSTI ID: 1378821
Report Number(s):
LLNL-JRNL-727659
Journal ID: ISSN 1070-664X
Grant/Contract Number:
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 9; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Brodrick, Jonathan P., Kingham, R. J., Marinak, M. M., Patel, M. V., Chankin, A. V., Omotani, J. T., Umansky, M. V., Del Sorbo, D., Dudson, B., Parker, J. T., Kerbel, G. D., Sherlock, M., and Ridgers, C. P. Testing nonlocal models of electron thermal conduction for magnetic and inertial confinement fusion applications. United States: N. p., 2017. Web. doi:10.1063/1.5001079.
Brodrick, Jonathan P., Kingham, R. J., Marinak, M. M., Patel, M. V., Chankin, A. V., Omotani, J. T., Umansky, M. V., Del Sorbo, D., Dudson, B., Parker, J. T., Kerbel, G. D., Sherlock, M., & Ridgers, C. P. Testing nonlocal models of electron thermal conduction for magnetic and inertial confinement fusion applications. United States. doi:10.1063/1.5001079.
Brodrick, Jonathan P., Kingham, R. J., Marinak, M. M., Patel, M. V., Chankin, A. V., Omotani, J. T., Umansky, M. V., Del Sorbo, D., Dudson, B., Parker, J. T., Kerbel, G. D., Sherlock, M., and Ridgers, C. P. Wed . "Testing nonlocal models of electron thermal conduction for magnetic and inertial confinement fusion applications". United States. doi:10.1063/1.5001079. https://www.osti.gov/servlets/purl/1393324.
@article{osti_1393324,
title = {Testing nonlocal models of electron thermal conduction for magnetic and inertial confinement fusion applications},
author = {Brodrick, Jonathan P. and Kingham, R. J. and Marinak, M. M. and Patel, M. V. and Chankin, A. V. and Omotani, J. T. and Umansky, M. V. and Del Sorbo, D. and Dudson, B. and Parker, J. T. and Kerbel, G. D. and Sherlock, M. and Ridgers, C. P.},
abstractNote = {Three models for nonlocal electron thermal transport are here compared against Vlasov-Fokker-Planck (VFP) codes to assess their accuracy in situations relevant to both inertial fusion hohlraums and tokamak scrape-off layers. The models tested are (i) a moment-based approach using an eigenvector integral closure (EIC) originally developed by Ji, Held, and Sovinec [Phys. Plasmas 16, 022312 (2009)]; (ii) the non-Fourier Landau-fluid (NFLF) model of Dimits, Joseph, and Umansky [Phys. Plasmas 21, 055907 (2014)]; and (iii) Schurtz, Nicolaï, and Busquet’s [Phys. Plasmas 7, 4238 (2000)] multigroup diffusion model (SNB). We find that while the EIC and NFLF models accurately predict the damping rate of a small-amplitude temperature perturbation (within 10% at moderate collisionalities), they overestimate the peak heat flow by as much as 35% and do not predict preheat in the more relevant case where there is a large temperature difference. The SNB model, however, agrees better with VFP results for the latter problem if care is taken with the definition of the mean free path. Additionally, we present for the first time a comparison of the SNB model against a VFP code for a hohlraum-relevant problem with inhomogeneous ionisation and show that the model overestimates the heat flow in the helium gas-fill by a factor of ~2 despite predicting the peak heat flux to within 16%.},
doi = {10.1063/1.5001079},
journal = {Physics of Plasmas},
number = 9,
volume = 24,
place = {United States},
year = {Wed Sep 06 00:00:00 EDT 2017},
month = {Wed Sep 06 00:00:00 EDT 2017}
}

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