Phase Mixing of Alfvén Waves Near a 2D Magnetic Null Point

McLaughlin, James (2013) Phase Mixing of Alfvén Waves Near a 2D Magnetic Null Point. Journal of Astrophysics and Astronomy, 34 (3). pp. 223-246. ISSN 0250-6335

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Official URL: http://dx.doi.org/10.1007/s12036-013-9174-8

Abstract

The propagation of linear Alfvén wave pulses in an inhomogeneous plasma near a 2D coronal null point is investigated. When a uniform plasma density is considered, it is seen that an initially planar Alfvén wavefront remains planar, despite the varying equilibrium Alfvén speed, and that all the wave collects at the separatrices. Thus, in the non-ideal case, these Alfvénic disturbances preferentially dissipate their energy at these locations. For a non-uniform equilibrium density, it is found that the Alfvén wavefront is significantly distorted away from the initially planar geometry, inviting the possibility of dissipation due to phase mixing. Despite this however, we conclude that for the Alfvén wave, current density accumulation and preferential heating still primarily occur at the separatrices, even when an extremely non-uniform density profile is considered.

Item Type: Article
Uncontrolled Keywords: Magnetohydrodynamics (MHD), waves, magnetic fields, Sun: atmosphere—corona
Subjects: F300 Physics
F500 Astronomy
F800 Physical and Terrestrial Geographical and Environmental Sciences
G100 Mathematics
Department: Faculties > Engineering and Environment > Mathematics and Information Sciences
Depositing User: James McLaughlin
Date Deposited: 04 Oct 2013 08:03
Last Modified: 28 Jan 2016 19:57
URI: http://nrl.northumbria.ac.uk/id/eprint/13790

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