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.
Highlights
Observations of downflows above large-scale post-flare arcades were first reported by McKenzie & Hudson (1999) on the basis of soft X-ray observations
In this paper we present an observation of a distinct downflow observed by SOHO/Extreme-ultraviolet Imaging Telescope (EIT) at 195 Å on 5-Mar.-2000
In this paper we present the evolution of the prominence, associated coronal mass ejection (CME) as well as the plasma downflow
Summary
Observations of downflows above large-scale post-flare arcades (supra-arcades) were first reported by McKenzie & Hudson (1999) on the basis of soft X-ray observations These downflows manifest themselves as dark structures moving through the corona towards the Sun with speeds in the range 45–500 km s−1. White-light features moving towards the Sun’s surface after CME lift-off have first been detected by Wang et al (1999) and Sheeley & Wang (2002) based on LASCO/C2 observations These coronal downflows occurred at altitudes of 3–5 R with speeds in the range of 50–200 km s−1. The inward moving features in white-light were observed as dark trails behind barely visible density enhancements with a cusp-like appearance These features were interpreted as observational signatures of the closing down of magnetic field lines which were dragged outward by CMEs, providing plausible evidence for the occurrence of magnetic reconnection processes. In this paper we present the evolution of the prominence, associated CME as well as the plasma downflow
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