Period Increase and Amplitude Distribution of Kink Oscillation of Coronal Loop

TL;DR

This study analyzes the evolution of coronal loop oscillations, revealing how changes in density and magnetic field strength influence oscillation periods and amplitude profiles, offering new insights into solar atmospheric diagnostics.

Contribution

It introduces a novel analysis of period increase and amplitude distribution in coronal loop oscillations using solar magneto-seismology, highlighting magnetic strength distribution effects.

Findings

Oscillation period increased from 1048 to 1264 seconds.

Density inside the loop increased while magnetic field strength decreased.

Amplitude profile deviations are linked to magnetic strength distribution.

Abstract

Coronal loops exist ubiquitously in the solar atmosphere. These loops puzzle astronomers over half a century. Solar magneto-seismology (SMS) provides a unique way to constrain the physical parameters of coronal loops. Here, we study the evolution of oscillations of a coronal loop observed by the Atmospheric Imaging Assembly (AIA). We measure geometric and physical parameters of the loop oscillations. In particular, we find that the mean period of the oscillations increased from 1048 to 1264 s during three oscillatory cycles. We employ the differential emission measure method and apply the tools of SMS. The evolution of densities inside and outside the loop is analyzed. We found that an increase of density inside the loop and decrease of the magnetic field strength along the loop are the main reasons for the increase in the period during the oscillations. Besides, we also found that the amplitude profile of the loop is different from a profile would it be a homogeneous loop. It is proposed that the distribution of magnetic strength along the loop rather than density stratification is responsible for this deviation. The variation in period and distribution of amplitude provide, in terms of SMS, a new and unprecedented insight into coronal loop diagnostics.