PPPL-5390
A nonlocal ion heat flux closure for antiparallel reconnection
Authors: J. Ng, A. Hakim, and A. Bhattacharjee
Abstract: The integration of kinetic effects in fluid models
is important for global simulations of the Earth's magnetosphere. In
particular, it has been shown that ion kinetics play a crucial role
in the dynamics of large reconnecting systems, and that higher-order
fluid moment models can account for some of these effects. Here we
introduce a ten-moment model for electrons and ions, which includes
the off diagonal elements of the pressure tensor that are important
for magnetic reconnection. Kinetic effects are recovered by
introducing a nonlocal heat flux closure, which approximates linear
Landau damping in the fluid framework. The closure is tested using
the island coalescence problem, which is sensitive to ion dynamics.
We demonstrate that the nonlocal closure is able to
self-consistently reproduce the structure of the ion diffusion
region, pressure tensor and ion velocity without the need for
fine-tuning of relaxation coefficients present in earlier models.
Submitted to: Physics of Plasmas
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Download PPPL-53901.6 MB (9 pp)
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