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

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.

arXiv comment19 pages, 14 figures

References in corpus (14)

• Nonlinear Fast Magnetoacoustic Wave Propagation in the Neighbourhood of a 2D magnetic X-point: Oscillatory Reconnection
• MHD wave propagation in the neighbourhood of a two-dimensional null point
• Current amplification and magnetic reconnection at a 3D null point. I - Physical characteristics
• Review article: MHD wave propagation near coronal null points of magnetic fields
• A new view of quiet-Sun topology from Hinode/SOT
• MHD mode coupling in the neighbourhood of a 2D null point
• Phase Mixing of Nonlinear Visco-resistive Alfvén Waves
• Magnetohydrodynamics wave propagation in the neighbourhood of two dipoles
• MHD Wave Propagation in the Neighbourhood of Two Null Points
• Steady state reconnection at a single 3D magnetic null point
• Current accumulation at an asymmetric 3D null point caused by generic shearing motions
• On ponderomotive effects induced by Alfven waves in inhomogeneous 2.5D MHD plasmas
• Linear and nonlinear MHD mode coupling of the fast magnetoacoustic wave about a 3D magnetic null point
• Pulse-driven nonlinear Alfvén waves and their role in the spectral line broadening

Cited by in corpus (2)

• Phase mixing of nonlinear Alfven waves
• The behaviour of magnetoacoustic waves in the neighbourhood of a two-dimensional null point: initially cylindrically-symmetric perturbations