Iranian Journal of Physics Research (May 2017)
Damping time of transverse kink oscillations in active region coronal loops observed by AIA/SDO
Abstract
A coronal loop can be oscillated in various directions. A basic type of coronal loop oscillation is called transverse oscillation that can be caused by different factors, such as nearby active regions and flares. The damping of transverse oscillation may be produced by the dissipation mechanism or the wake of the traveling disturbance. The aim of this paper is to estimate the damping time of transverse (kink) coronal loop oscillations and the quantitative dependence of these oscillations on their frequencies in the solar corona loops that are situated near an active region with the Atmospheric Imaging Assembly (AIA) onboard Solar Dynamic Observatory (SDO). The observed data on 2014-Oct-17, consisting of 130 images with an interval of 24 seconds in the 171 A0 pass band is analyzed for evidence of transvers kink oscillations along the coronal loops and for estimate of physical parameters by fast Fourier transform (FFT) of data times series. In this analyzed signatures of transvers oscillations that are damped rapidly were found, with oscillation periods in the range of P=2-9.5 minutes. Also, damping times and damping qualities of filtered intensities centered on the dominant frequencies are measured in the range of minutes and , respectively. The observational results of this study indicate that the damping times increase with increasing the oscillation periods, and are highly sensitive function of oscillation period, but damping qualities are not very sensitive to the oscillations period. The order of magnitude of the damping times and damping qualities that obtained from this analysis are in good agreement with previous findings by authors and the theoretical prediction for damping of fast kink mode oscillations.
