Weak damping of propagating MHD kink waves in the quiescent corona

TL;DR

This study analyzes propagating MHD kink waves in the quiet Sun's corona, revealing they are weakly damped and suggesting a complex density structure that impacts energy transfer and coronal heating.

Contribution

It provides the first large-scale observational evidence of weak damping of kink waves in the quiescent corona and links wave damping to coronal density variations.

Findings

Kink waves are weakly damped in the quiet Sun.

The corona exhibits a spectrum of density ratios.

Energy transfer from waves to plasma is limited by weak damping.

Abstract

Propagating transverse waves are thought to be a key transporter of Poynting flux throughout the Sun's atmosphere. Recent studies have shown that these transverse motions, interpreted as the magnetohydrodynamic kink mode, are prevalent throughout the corona. The associated energy estimates suggest the waves carry enough energy to meet the demands of the coronal radiative losses in the quiescent Sun. However, it is still unclear how the waves deposit their energy into the coronal plasma. We present the results from a large-scale study of propagating kink waves in the quiescent corona using data from the Coronal Multi-channel Polarimeter (CoMP). The analysis reveals that the kink waves appear to be weakly damped, which would imply low rates of energy transfer from the large-scale transverse motions to smaller-scales via either uni-turbulence or resonant absorption. This raises questions about how the observed kink modes would deposit their energy into the coronal plasma. Moreover, these observations, combined with the results of Monte Carlo simulations, lead us to infer that the solar corona displays a spectrum of density ratios, with a smaller density ratio (relative to the ambient corona) in quiescent coronal loops and a higher density ratio in active region coronal loops.