Evidence for magnetic reconnection in the high corona

School of Physics and Astronomy, University of Birmingham, B15 2TT, UK

Corresponding author: gms@star.sr.bham.ac.uk

Received: 17 September 2003
Accepted: 5 November 2003

Abstract

The LASCO C2 coronagraph on the SOHO spacecraft shows many examples of oppositely-directed mass flows along the same (projected) radius vector. We have analysed 40 such events to understand their origin and possible physical cause. The events all had the speed of the outflowing feature higher than that of the inflowing feature. This is interpreted as reflecting an energy release in the outflowing solar wind. 19 of the 40 events had speed differences between 75 and 165 km s^-1, with the median speed difference being 112 km s^-1. One consequence of this is that the typical solar wind speed at the site of the event onset is around 60 km s^-1. Back projection of the altitude-time plots gives an estimate of the height in the corona of the originating event. For 38 of the 40 events this (projected) height is between 3.1 and 4.2 solar radii. One plausible interpretation of the physical mechanism responsible for the events is magnetic reconnection as first described by Petschek ([CITE]).