Published 2009 | Version v1
Journal article

Alfvén wave filamentation and dispersive phase mixing in a high-density channel: Landau fluid and hybrid simulation

Description

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.

Abstract

International audience

Additional details

Identifiers

URL
https://hal.archives-ouvertes.fr/hal-00387937
URN
urn:oai:HAL:hal-00387937v1