Period Increase and Amplitude Distribution of Kink Oscillation of Coronal Loop

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.

References in corpus (11)

• Observational Tests of Damping by Resonant Absorption in Coronal Loop Oscillations
• Alfven Waves in the Solar Atmosphere
• Solar Corona Loop Studies with AIA: I. Cross-Sectional Temperature Structure
• The formation heights of coronal shocks from 2D density and Alfvén speed maps
• Observations of sausage modes in magnetic pores
• Modeling Magnetic Field Structure of a Solar Active Region Corona using Nonlinear Force-Free Fields in Spherical Geometry
• Pre-flare coronal dimmings
• Longitudinal oscillations in density stratified and expanding solar waveguides
• Magnetic Jam in the Corona of the Sun
• Quasi-periodic pulsations with multiple periods in hard X-ray emission
• Transverse kink oscillations of expanding coronal loops