LAUSR

We investigate the transverse coronal-loop oscillations induced by the eruption of a prominence-carrying flux rope on 7 December 2012. The flux rope originating from NOAA Active Region (AR) 11621 was observed in extremeultraviolet (EUV) wavelengths by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) spacecraft and in Hα line center by the ground-based telescope at the Big Bear Solar Observatory (BBSO). The early evolution of the flux rope is divided into two steps: a slow rise phase at a speed of ≈230 km s−1 and a fast rise phase at a speed of ≈706 km s−1. The eruption generates a C5.8 flare and the onset of the fast rise is consistent with the hard X-ray (HXR) peak time of the flare. The embedded prominence has a lower speed of ≈452 km s−1. The eruption is significantly inclined from the local solar normal by ≈60◦, suggesting a typical non-radial eruption. During the early eruption of the flux rope, the nearby coronal loops are disturbed and experience independent kink-mode oscillations in the horizontal and vertical directions. The oscillation in the horizontal direction has an initial amplitude of ≈3.1 Mm, a period of ≈294 seconds, and a damping time of ≈645 seconds. It is most striking in 171 Å and lasts for three to four cycles. The oscillations in the vertical directions are observed mainly in 171, 193, and 211 Å. The initial amplitudes lie in the range of 3.4 – 5.2 Mm, with an average value of 4.5 Mm. The periods are between 407 seconds and 441 seconds, with an average value of 423 seconds. The oscillations are damping and last for nearly four cycles. The damping times lie in the range of 570 – 1012 seconds, with an average value of 741 seconds. Assuming a semi-circular shape of the vertically oscillating loops, we calculate the loop lengths according to their heights. Using the observed periods, we carry out coronal seismology and estimate the internal Alfvén speeds B Q.M. Zhang [email protected] 1 Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, CAS, Nanjing 210023, China 2 School of Astronomy and Space Science, University of Science and Technology of China, Hefei 230026, China SOLA: ms_lst.tex; 20 January 2022; 1:45; p. 1 ar X iv :2 20 1. 07 38 9v 1 [ as tr oph .S R ] 1 9 Ja n 20 22