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www.nonlin-processes-geophys.net/16/275/2009/
doi:10.5194/npg-16-275-2009
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Alfvén wave filamentation and dispersive phase mixing in a high-density channel: Landau fluid and hybrid simulations
1Université de Nice Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur, B.P. 4229, 06304 Nice Cedex 4, France
2Institute of Atmospheric Physics and Astronomical Institute, AS CR Bocni II/1401, 14131 Prague, Czech Republic
Abstract. The propagation of dispersive Alfvén waves in a low-beta collisionless plasma with a high-density channel aligned with the ambient magnetic field, is studied in three space dimensions. A fluid model retaining linear Landau damping and finite Larmor radius corrections is used, together with a hybrid particle-in-cell simulation aimed to validate the predictions of this Landau-fluid model. It is shown that when the density enhancement is moderate (depending on the pump wavelength and the plasma parameters), the wave energy concentrates into a filament whose transverse size is prescribed by the dimension of the channel. In contrast, in the case of a stronger density perturbation, the early formation of a magnetic filament is followed by the onset of thin helical ribbons and the development of strong gradients. This "dispersive phase mixing" provides a mechanism permitting dissipation processes (not included in the present model) to act and heat the plasma.
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Citation: Borgogno, D., Hellinger, P., Passot, T., Sulem, P. L., and Trávníček, P. M.: Alfvén wave filamentation and dispersive phase mixing in a high-density channel: Landau fluid and hybrid simulations, Nonlin. Processes Geophys., 16, 275-285, doi:10.5194/npg-16-275-2009, 2009. Bibtex EndNote Reference Manager XML
