Comparison of damping mechanisms for transverse waves in solar coronal loops

Abstract

We present a method to assess the plausibility of alternative mechanisms to explain the damping of magnetohydrodynamic (MHD) transverse waves in solar coronal loops. The considered mechanisms are resonant absorption of kink waves in the Alfvén continuum, phase-mixing of Alfvén waves, and wave leakage. Our methods make use of Bayesian inference and model comparison techniques. We first infer the values for the physical parameters that control the wave damping, under the assumption of a particular mechanism, for typically observed damping time-scales. Then, the computation of marginal likelihoods and Bayes factors enable us to quantify the relative plausibility between the alternative mechanisms. We find that, in general, the evidence is not large enough to support a single particular damping mechanism as the most plausible one. Resonant absorption and wave leakage offer the most probable explanations in strong damping regimes, while phase mixing is the best candidate for weak/moderate damping. When applied to a selection of 89 observed transverse loop oscillations, with their corresponding measurements of damping times scales and taking into account data uncertainties, we find that only in a few cases positive evidence for a given damping mechanism is available.

References in corpus (5)

• Bayes in the sky: Bayesian inference and model selection in cosmology
• First direct measurements of transverse waves in solar polar plumes using SDO/AIA
• Damping of filament thread oscillations: effect of the slow continuum
• On the scaling of the damping time for resonantly damped oscillations in coronal loops
• Determination of the cross-field density structuring in coronal waveguides using the damping of transverse waves

Cited by in corpus (5)

• Novel data analysis techniques in coronal seismology
• Resonant absorption: transformation of compressive motions into vortical motions
• Inference of magnetic field strength and density from damped transverse coronal waves
• Inferring physical parameters in solar prominence threads
• Quantifying the evidence for resonant damping of coronal waves with foot-point wave power asymmetry