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Title: Parallel transport of long mean-free-path plasma along open magnetic field lines: Parallel heat flux

Abstract

In a long mean-free-path plasma where temperature anisotropy can be sustained, the parallel heat flux has two components with one associated with the parallel thermal energy and the other the perpendicular thermal energy. Due to the large deviation of the distribution function from local Maxwellian in an open field line plasma with low collisionality, the conventional perturbative calculation of the parallel heat flux closure in its local or non-local form is no longer applicable. Here, a non-perturbative calculation is presented for a collisionless plasma in a two-dimensional flux expander bounded by absorbing walls. Specifically, closures of previously unfamiliar form are obtained for ions and electrons, which relate two distinct components of the species parallel heat flux to the lower order fluid moments such as density, parallel flow, parallel and perpendicular temperatures, and the field quantities such as the magnetic field strength and the electrostatic potential. The plasma source and boundary condition at the absorbing wall enter explicitly in the closure calculation. Although the closure calculation does not take into account wave-particle interactions, the results based on passing orbits from steady-state collisionless drift-kinetic equation show remarkable agreement with fully kinetic-Maxwell simulations. As an example of the physical implications of the theory,more » the parallel heat flux closures are found to predict a surprising observation in the kinetic-Maxwell simulation of the 2D magnetic flux expander problem, where the parallel heat flux of the parallel thermal energy flows from low to high parallel temperature region.« less

Authors:
;  [1]
  1. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
Publication Date:
OSTI Identifier:
22072461
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 19; Journal Issue: 6; Other Information: (c) 2012 American Institute of Physics; 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; ANISOTROPY; BOUNDARY CONDITIONS; CLOSURES; COLLISIONLESS PLASMA; DISTRIBUTION FUNCTIONS; ELECTRONS; HEAT FLUX; IONS; KINETIC EQUATIONS; MAGNETIC FIELDS; MAGNETIC FLUX; MAXWELL EQUATIONS; MEAN FREE PATH; PARTICLE INTERACTIONS; PLASMA SIMULATION; STEADY-STATE CONDITIONS; TEMPERATURE DEPENDENCE; TWO-DIMENSIONAL CALCULATIONS

Citation Formats

Zehua, Guo, and Xianzhu, Tang. Parallel transport of long mean-free-path plasma along open magnetic field lines: Parallel heat flux. United States: N. p., 2012. Web. doi:10.1063/1.4725494.
Zehua, Guo, & Xianzhu, Tang. Parallel transport of long mean-free-path plasma along open magnetic field lines: Parallel heat flux. United States. https://doi.org/10.1063/1.4725494
Zehua, Guo, and Xianzhu, Tang. Fri . "Parallel transport of long mean-free-path plasma along open magnetic field lines: Parallel heat flux". United States. https://doi.org/10.1063/1.4725494.
@article{osti_22072461,
title = {Parallel transport of long mean-free-path plasma along open magnetic field lines: Parallel heat flux},
author = {Zehua, Guo and Xianzhu, Tang},
abstractNote = {In a long mean-free-path plasma where temperature anisotropy can be sustained, the parallel heat flux has two components with one associated with the parallel thermal energy and the other the perpendicular thermal energy. Due to the large deviation of the distribution function from local Maxwellian in an open field line plasma with low collisionality, the conventional perturbative calculation of the parallel heat flux closure in its local or non-local form is no longer applicable. Here, a non-perturbative calculation is presented for a collisionless plasma in a two-dimensional flux expander bounded by absorbing walls. Specifically, closures of previously unfamiliar form are obtained for ions and electrons, which relate two distinct components of the species parallel heat flux to the lower order fluid moments such as density, parallel flow, parallel and perpendicular temperatures, and the field quantities such as the magnetic field strength and the electrostatic potential. The plasma source and boundary condition at the absorbing wall enter explicitly in the closure calculation. Although the closure calculation does not take into account wave-particle interactions, the results based on passing orbits from steady-state collisionless drift-kinetic equation show remarkable agreement with fully kinetic-Maxwell simulations. As an example of the physical implications of the theory, the parallel heat flux closures are found to predict a surprising observation in the kinetic-Maxwell simulation of the 2D magnetic flux expander problem, where the parallel heat flux of the parallel thermal energy flows from low to high parallel temperature region.},
doi = {10.1063/1.4725494},
url = {https://www.osti.gov/biblio/22072461}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 6,
volume = 19,
place = {United States},
year = {2012},
month = {6}
}