A Long-Duration Solar Flare with Mass Ejection and Global Consequences

Abstract

view Abstract Citations (176) References (15) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Long-Duration Solar Flare with Mass Ejection and Global Consequences Hudson, H. S. ; Acton, L. W. ; Freeland, S. L. Abstract We report observations of a long-duration flare with mass ejection from the corona, using the Yohkoh soft X-ray telescope (SXT). This flare occurred 1994 November 13 near disk center during quiet solar conditions, with excellent temporal coverage of both the core activity in the active region itself and of the global corona. The initial X-ray images reveal two arcades of cusped magnetic loops, connected via a series of thin loops. These loops rise rapidly during the increasing phase of soft X-ray flare brightness. In its final state, the flare has the configuration of postflare loops with a cusp. Large regions of the X-ray corona appear to empty during the evolution of the event. We suggest that this corresponds a coronal mass ejection (CME) seen in soft X-rays. Its detection in the SXT images is consistent with the finding that material participating in a CME exists at elevated coronal temperatures (2.8 x 106 K in this case) before the ejection. We estimate a mass >4 x 1014 g for the ejected material. The X-ray morphology of the event has strong points of similarity with the classical reconnection picture of long-duration event (LDE) formation, but there are significant discrepancies: there is no observed inward flow during the rise phase, the expansions are multiple and appear to be nonradial, and none of the observed motions suggest a reconnection jet. We note the subsequent occurrence of very large scale coronal disturbances, including regions near the boundaries of coronal holes at both poles. We suggest that this global disturbance implies a perturbation reaching as far outward as the heliospheric neutral sheet. The exciter would require a horizontal velocity of approximately 200 km s-1 in such a case, consistent with the projected velocity of the plasma cloud that we identify with a CME in the process of launching. Publication: The Astrophysical Journal Pub Date: October 1996 DOI: 10.1086/177894 Bibcode: 1996ApJ...470..629H Keywords: SUN: FLARES; SUN: CORONA; SUN: MAGNETIC FIELDS; SUN: PARTICLE EMISSION full text sources ADS |