Abstract:
We analyze two flare events that occurred in active region NOAA 501 on 20 November 2003. The Hα and magnetogram measurements show interaction between two filaments, which produced a slowly rising flare event, corresponding
to two stages of magnetic reconnection. The relative clockwise rotation between
the two sunspot systems caused filament destabilization. The cusp-shaped magnetic
field in the main phase of the second flare and its evolution in correlation with ribbon
separation provide evidence for the cause of the CME eruption. The propagation and
orientation of the CME with respect to the ecliptic plane is illustrated by IPS images.
