Heat flux viscosity in collisional magnetized plasmas
Authors: C. Liu, W. Fox, and A. Bhattacharjee
Abstract: Momentum transport in collisional
magnetized plasmas due to gradients in the heat flux, a "heat flux
viscosity", is demonstrated. Even though no net particle flux is
associated with a heat flux, in a plasma there can still be
momentum transport owing to the velocity dependence of the Coulomb
collision frequency, analogous to the thermal force. This
heat-flux viscosity may play an important role in numerous plasma
environments, in particular in strongly-driven high-energy-density
plasma, where strong heat flux can dominate over ordinary plasma
flows. The heat flux viscosity can influence the dynamics of the
magnetic fi eld in plasmas through the generalized Ohm's law, and
may therefore play an important role as a dissipation mechanism
allowing magnetic field line reconnection. The heat flux
viscosity is calculated directly using the fi nite-diff erence
method of E. M. Epperlein and M. G. Haines [M. G. Haines, Phys.
Fluids 29, 1029 (1986)], which is shown to be more accurate than
S. I. Braginskii's method [S. I. Braginskii, Rev. Plasma Phys. 1,
205 (1965)], and con firmed with one-dimensional collisional
particle-in-cell simulations. The resulting transport
coefficients are tabulated for ease of application.
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Submitted to: Physics of Plasmas
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Download PPPL-5149 (pdf 1.9 MB 20pp)
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