Coronal Structure of a Flaring Region and Associated Coronal Mass Ejection

Abstract

We report the multiwavelength investigations of an eruptive flare event that occurred on 2001 April 2 at about 11 UT. The manifestations associated with this flare event have been studied from the near-Sun region to about 0.5 AU. The Hα images from the Meudon Spectroheliograph reveal a fast spectacular eruption of plasmoids from the flare site to the west and a Moreton wave disturbance propagating toward the south. A bright, fast, wide coronal mass ejection (CME) associated with this eruptive event was imaged by SOHO/LASCO and the remote-sensing interplanetary scintillation technique. The radio measurements from the Nançay Radioheliograph and Tremsdorf Radio Telescope have been useful in identifying the radio signatures of the CME's initiation. The metric type II radio bursts produced at the time of CME onset also propagate toward the west, and their positions coincide with the magnetic null point, which was located at the southwest part of NOAA active region 9393. The timings and positions of the radio bursts, the Hα eruption, and the CME onset as well as the magnetic field configuration suggest a release of energy at the null point, and as indicated by the Moreton wave, the eruption starts close to the chromospheric or low coronal level. The results support the ``breakout'' scenario proposed by S. Antiochos and coworkers, and they are also suggestive that the energy release is followed by magnetic reconnection between the low-lying loops near the separatrix and the loop system above them.