30-min Decayless Kink Oscillations in a Very Long Bundle of Solar Coronal Plasma Loops

TL;DR

This study observes long-lasting decayless kink oscillations in very long solar coronal loops, revealing a persistent 30-minute periodicity that supports non-resonant energy mechanisms crucial for understanding coronal heating.

Contribution

It provides the first detailed observation of decayless kink oscillations in extremely long coronal loops, highlighting a 30-minute periodicity and supporting non-resonant energy transfer models.

Findings

Oscillations lasted several hours in very long loops.

Detected a consistent 30-minute periodicity.

Supports non-resonant mechanisms for wave damping.

Abstract

The energy balance in the corona of the Sun is the key to the long-standing coronal heating dilemma, which could be potentially revealed by observational studies of decayless kink oscillations of coronal plasma loops. A bundle of very long off-limb coronal loops with the length of $736\pm80$ Mm and a lifetime of about 2 days are found to exhibit decayless kink oscillations. The oscillations were observed for several hours. The oscillation amplitude was measured at 0.3-0.5 Mm, and the period at 28-33 min. The existence of 30-min periodicity of decayless kink oscillations indicates that the mechanism compensating the wave damping is still valid in such a massive plasma structure. It provides important evidence for the non-resonant origin of decayless kink oscillations with 2-6min periods, i.e., the lack of their link with the leakage of photospheric and chromospheric oscillations into the corona and the likely role of the broadband energy sources. Magnetohydrodynamic seismology based on the reported detection of the kink oscillation, with the assistance of the differential emission measure analysis and a background coronal model provides us with a comprehensive set of plasma and magnetic field diagnostics, which is of interest as input parameters of space weather models.