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Comparisons of Kinetic Effects on Heat Transport to Classical Fluid Models in Magnetized Gaspipes on NIF

ORAL

Abstract

e present simulations of electron heat flow relevant to magnetized gaspipe experiments on NIF to

investigate kinetic effects on transport phenomena. These D2 and neopentane (C5H12) filled gas pipe

targets are used to study the laser preheat stage of a MagLIF scheme where an axial magnetic field is

applied to the target[1]. Initial simulations of were done with the radiation-MHD code Hydra with a

collision-dominated fluid model. However, the Knudsen number, the ratio between the electron mean

free path and temperature scale lengths, was found to exceed 0.01 in substantial regions of space in-

dicating the regime where non-local effects are important for heat flow. Motivated for further kinetic

study, we utilize Hydra to initialize our plasma conditions and couple it with the Vlasov-Fokker-Planck

K2 code[2] in both 1D and 2D until a steady state is reached to examine the impact of kinetic effects

on heat transport. Collisional-fluid models such as Braginskii or Spitzer-Harm overpredict the kinetic

heatflux by 50% in certain regions while underpredicting the heatflux in enhanced pre-heat regions in

the cold gas. This talk will discuss the comparisons and calculations between the extracted kinetic heat

flux from K2, classical transport models, and the reduced-nonlocal model of Schurtz 3

Publication: 1 B. Pollock, et. al. Phys. Plasmas (2023)<br>2 M. Sherlock, J. P. Brodrick, and C. P. Ridgers, Phys. Plasmas 24, 082706 (2017).<br>3 Schurtz et al., Phys. Plasmas 7, 4238 (2000)

Presenters

  • Ryan Y Lau

    University of Colorado, Boulder

Authors

  • Ryan Y Lau

    University of Colorado, Boulder

  • David J Strozzi

    Lawrence Livermore Natl Lab, LLNL, Lawrence Livermore National Laboratory

  • Mark W Sherlock

    Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory

  • William A Farmer

    Lawrence Livermore National Laboratory, Lawrence Livermore Natl Lab

  • Yuan Shi

    University of Colorado Boulder, Lawrence Livermore Natl Lab, University of Colorado Boulder/Lawrence Livermore National Laboratory, Lawrence Livermore National Lab

  • Matt R Weis

    Sandia National Laboratories

  • John R Cary

    University of Colorado, Boulder