Dynamics of Explosive Events by Interface Region Imaging Spectrograph

E. Tavabi, S. Zeighami, M. Heydari

Published 2022-07-03Version 1

In this research, we investigate Explosive Events (EEs) in the off-limb solar atmosphere, with simultaneous observations from the Si IV, Mg II k, and slit-jaw images (SJI) based on the Interface Region Imaging Spectrograph (IRIS), in 2014 August 17, and February 19. IRIS data can be investigated to observe the motion of matter, fluctuations, energy absorption, and heat transition of the solar atmosphere. Mechanisms responsible for solar large-scale structures, such as flares and coronal mass ejections might be originated from these small-scale energetic events. Therefore, the study of these events can be helpful for understanding mechanisms in mass and energy transporting from the chromosphere toward the transition region and corona. We obtain intensity profiles from spectra in two altitudes i.e., solar limb and 5 arcsec distance from solar limb, and then analyze the EEs fluctuations at two altitudes along the slit. We observed that some line profiles of spectra show enhancements in blue and red wings indicating outward and downward flows, and some profiles represent opposite EEs on their both wings. The Amplitude of the Doppler velocity in two data for the two altitudes was approximated to be about 50 km/s. We calculated the phase velocity of the oscillations using a technique based on cross-correlation. The phase velocity is obtained as about 220 km/s. According to the periodic red and blue enhancements in EEs, we suggested that the fluctuations in the EEs with one side enhancement indicate the swaying motions of spicules over their axes, and those EEs observed on both wings indicate the rotational motions of spicules. The swaying and rotating motions are responsible for the kink and twisted waves respectively.