Clear Evidence of Reconnection Inflow of a Solar Flare

Abstract

We found an important piece of evidence for magnetic reconnection inflow in a flare on 1999 March 18. The flare occurred on the northeast limb, displaying a nice cusp-shaped soft X-ray loop and a plasmoid ejection typical for the long-duration events. The EUV observation of the same flare shows us a bubble-like void ejection. The core of this EUV void corresponds to the soft X-ray plasmoid. Moreover, as this void is ejected, magnetic reconnection occurs at the disconnecting point. A clear ongoing pattern toward the magnetic X-point is seen. The velocity of this apparent motion is about 5 km s-1, which is an upper limit on reconnection inflow speed. Based on this observation, we derive the reconnection rate as MA = 0.001-0.03, where MA is an Alfven Mach number of the inflow.