Extreme Ultraviolet (EUV) Waves in the Solar Corona Observed by the Solar Dynamics Observatory (SDO)

The magnetized solar corona hosts a variety of waves that can be observed in extreme ultraviolet (EUV) from space-borne telescopes. These waves offer valuable clues for diagnosing the physical conditions on the Sun. We report (1) a focused case study of a global EUV wave associated with the X8.2 flare and coronal mass ejection (CME) on September 10, 2017 and (2) a systematic survey of quasi-period fast-mode propagating wave trains (QFPs) generally associated with solar flares. We analyzed the EUV data from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) and measured the wave speeds using various space-time diagrams. Such measurements, in combination with plasma density estimates, can be used to infer the magnetic field strengths in the solar corona, an important quantity currently difficult to measure directly.