Three-Dimensional Propagation of Kink Wave Trains in Solar Coronal Slabs

Abstract

Impulsively excited wave trains are of considerable interest in solar coronal seismology. To our knowledge, however, it remains to examine the three-dimensional (3D) dispersive propagation of impulsive kink waves in straight, field-aligned, symmetric, low-beta, slab equilibria that are structured only in one transverse direction. We offer a study here, starting with an analysis of linear oblique kink modes from an eigenvalue problem perspective. Two features are numerically found for continuous and step structuring alike, one being that the group and phase velocities may lie on opposite sides of the equilibrium magnetic field (${\vec{B}}_0$), and the other being that the group trajectories extend only to a limited angle from ${\vec{B}}_0$. We justify these features by making analytical progress for the step structuring. More importantly, we demonstrate by a 3D time-dependent simulation that these features show up in the intricate interference patterns of kink wave trains that arise from a localized initial perturbation. In a plane perpendicular to the direction of inhomogeneity, the large-time slab-guided patterns are confined to a narrow sector about ${\vec{B}}_0$, with some wavefronts propagating toward ${\vec{B}}_0$. We conclude that the phase and group diagrams lay the necessary framework for understanding the complicated time-dependent behavior of impulsive waves.

arXiv comment5 pages, 4 figures, accepted for publication in MNRAS Letters

References in corpus (13)

• MPI-AMRVAC 2.0 for Solar and Astrophysical Applications
• On the nature of kink MHD waves in magnetic flux tubes
• Nonlinear Instability of kink oscillations due to shear motions
• Surface Alfven waves in solar flux tubes
• Kink oscillations of coronal loops
• Magnetohydrodynamic kink waves in nonuniform solar flux tubes: phase mixing and energy cascade to small scales
• Propagation and dispersion of transverse wave trains in magnetic flux tubes
• Resonantly damped surface and body MHD waves in a solar coronal slab with oblique propagation
• Fast magnetoacoustic wave trains: from tadpoles to boomerangs
• Impulsively generated wave trains in coronal structures: II. Effects of transverse structuring on sausage waves in pressureless slabs
• Resonant Damping of Kink Modes in Solar Coronal Slabs
• Standing Sausage Perturbations in solar coronal loops with diffuse boundaries: An initial-value-problem perspective
• Impulsively Generated Kink Wave Trains in Solar Coronal Slabs

Cited by in corpus (2)

• Traveling kink oscillations of coronal loops launched by a solar flare
• Standing Sausage Perturbations in Solar Coronal Slabs with Continuous Transverse Density Profiles: cutoff wavenumbers, evanescent eigenmodes, and oscillatory continuum