Alfvén wave filamentation and dispersive phase mixing in a high-density channel: Landau fluid and hybrid simulations
| Autor: | D. Borgogno, P. Hellinger, T. Passot, P. L. Sulem, P. M. Trávníček |
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| Jazyk: | angličtina |
| Rok vydání: | 2009 |
| Předmět: | |
| Zdroj: | Nonlinear Processes in Geophysics, Vol 16, Iss 2, Pp 275-285 (2009) |
| Druh dokumentu: | article |
| ISSN: | 1023-5809 1607-7946 |
| Popis: | 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. |
| Databáze: | Directory of Open Access Journals |
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