Observations of Excitation and Damping of Transversal Oscillations in Coronal Loops by AIA/SDO

Abstract

The excitation and damping of transversal coronal loop oscillations and quantitative relation between damping time, damping quality (damping time per period), oscillation amplitude, dissipation mechanism and the wake phenomena are investigated. The observed time series data with the \textit{Atmospheric Imaging Assembly} (AIA) telescope on NASA's \textit{Solar Dynamics Observatory} (SDO) satellite on 2015 March 2, consisting of 400 consecutive images with 12 seconds cadence in the 171 $ \rm{{\AA}}$ pass band is analyzed for evidence of transversal oscillations along the coronal loops by Lomb-Scargle periodgram. In this analysis signatures of transversal coronal loop oscillations that are damped rapidly were found with dominant oscillation periods in the range of $\rm{P=12.25-15.80}$ minutes. Also, damping times and damping qualities of transversal coronal loop oscillations at dominant oscillation periods are estimated in the range of $ \rm{\tau_d=11.76-21.46}$ minutes and $ \rm{\tau_d/P=0.86-1.49}$, respectively. The observational results of this analysis show that damping qualities decrease slowly with increasing the amplitude of oscillation, but periods of oscillations are not sensitive function of amplitude of oscillations. The order of magnitude of the damping qualities and damping times are in good agreement with previous findings and the theoretical prediction for damping of kink mode oscillations by dissipation mechanism. Furthermore, oscillation of loop segments attenuate with time roughly as $t^{-\alpha}$ that magnitude values of $\alpha$ for 30 different segments change from 0.51 to 0.75.