Testing nonlocal models of electron thermal conduction for magnetic and inertial confinement fusion applications
Artikel i vetenskaplig tidskrift, 2017

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%.

Författare

J. P. Brodrick

University of York

R. J. Kingham

Imperial College London

M. M. Marinak

Lawrence Livermore National Laboratory

M. V. Patel

Lawrence Livermore National Laboratory

A. V. Chankin

Max Planck-institutet

John Omotani

Chalmers, Fysik, Subatomär fysik och plasmafysik

M. V. Umansky

Lawrence Livermore National Laboratory

D. Del Sorbo

University of York

B. Dudson

University of York

J. T. Parker

Rutherford Appleton Laboratory

G. D. Kerbel

Lawrence Livermore National Laboratory

M. Sherlock

Lawrence Livermore National Laboratory

C. P. Ridgers

University of York

Physics of Plasmas

1070-664X (ISSN) 1089-7674 (eISSN)

Vol. 24 092309

Ämneskategorier

Maskinteknik

DOI

10.1063/1.5001079