Paper Title:
Direct Observations of Magnetic Reconnection Sites of A CME/Flare of

Author List:
Lin, J., Ko, Y.-K., Sui, L., et al.

Abstract:
The event of November 18, 2003 provides us with an opportunity to
observe directly the current sheet and the associated magnetic
reconnection process. This event occurred on the east limb of the Sun, a
group of bright arcades in EIT 195 distributing at both sides of the
equator can be seen clearly prior to the eruption. The EIT 195 movie
shows that the arcades located at the central position started to change
at around 08:48UT and the following significant variation occurs at
9:00UT with a fast expansion of the arcade. No apparent filament or
prominence showed. Two legs of the stretched arcade show apparent motion
of approaching one another, which implies a magnetic reconnection
process driven by the eruption. Consequently, a bright and sharp cusp
structure forms and moves upwards. From 11:24UT, the visible top of the
cusp structure started getting round and its height also decreases,
manifesting an apparent shrinkage process. A sharp cusp can still be
seen in MK4 images. Correspondingly, the front of a fast CME appears in
the field of view of LASCO/C2 from 9:26UT, showing typical
three-component structure of CMEs with a big bright core. The CME front
left the field of view of LASCO/C2 after 10:50UT and following the
entangled structure of CME, a long and thin streamer-like feature
appears in the field of view of LASCO/C2, and a series bright blobs
successively flow away from the Sun along this feature. The average
velocity of the CME front within the time interval sweeping the field of
view of LASCO/C2 is 1700 km/s and that of the CME core is 1412 km/s.
Comparisons with the similar feature investigated by Ko et al (2003)
suggest that this long and thin streamer-like feature be the current
sheet forming and developing during this CME-flare process. Observations
made by UVCS caught the initial stage of this eruption when the magnetic
arcade thrust upward pushing the adjacent magnetic field and plasma
away. The data from RHESSI show significant hard X-ray emission at both
the footpoints and the top of the cusp structure, which further confirms
the undergoing magnetic reconnection in the progress of eruption.