Coordinated observations of large scale coronal brightening and Hα surge

Abstract

During the post-flare phase of an eruptive two-ribbon flare on February 4, 1995, the Soft X-ray Telescope (SXT) on board Yohkoh observed the rapid brightening of a set of large scale coronal loops (150–200 Mm in length). Simultaneously, coordinated ground-based observations reveal a coincident Hα surge event. To our knowledge, no Hα surge event coincident with the large scale coronal brightening observed by Yohkoh has been reported. The possible mechanisms for the concurrent cool plasma ejection and the filling of the hot coronal loops are discussed. It is found that magnetic reconnection between a magnetic arcade and an overlying large scale coronal structure may account for the coincident events. Big amount of magnetic energy was converted into both mechanic energy (about 1022J) in the mass ejection and thermal radiation (1023J) contained in the large SXR loops.