Observation of a bright coronal downflow by SOHO/EIT

Abstract

A distinct coronal downflow has been discovered in the course of a prominence eruption associated coronal mass ejection (CME) imaged by EIT ( Extreme ultraviolet Imaging Telescope) and LASCO ( Large Angle Spectrometric Coronagraph) on board SOHO ( Solar and Heliospheric Observatory) on 5-Mar.-2000. Evolution of the prominences seen by EIT was tracked into the LASCO/ C2 and C3 field-of-view where they developed as the core of a typical three-part CME. In contrast to the inflow structures reported earlier in the literatures, which were dark and were interpreted as plasma voids moving down, the downflow reported here was bright. The downflow, which was only seen in EIT FOV had an onset time that coincided with the deceleration phase of the core of the CME. The downflow showed a rapid acceleration followed by a strong deceleration. The downflow followed a curved path which may be explained by material following the apex of a contracting magnetic loop sliding down along other field lines, although other explanations are also possible. Irrespective of the detailed geometry, this observation provides support for the pinching off of the field lines drawn-out by the erupting prominences and the contraction of the arcade formed by the reconnection.