Abstract:
We analyze Hα images, soft X-ray profiles, magnetograms, extreme ultra-violet images and, radio observations of
two homologous flare events (M1.4/1N and M9.6/2B) on 2003 November 20 in the active region NOAA 10501
and study properties of reconnection between twisted filament systems, energy release, and associated launch of
coronal mass ejections. During both events twisted filaments observed in Hα approached each other and initiated
the flare processes. However, the second event showed the formation of cusp as the filaments interacted. The
rotation of sunspots of opposite polarities, inferred from the magnetograms likely powered the twisted filaments
and injection of helicity. Along the current sheet between these two opposite polarity sunspots, the shear was
maximum, which could have caused the twist in the filament. At the time of interaction between filaments, the
reconnection took place and flare emission in thermal and nonthermal energy ranges attained the maximum. The
radio signatures revealed the opening of field lines resulting from the reconnection. The Hα images and radio
data provide the inflow speed leading to reconnection and the scale size of the particle acceleration region. The
first event produced a narrow and slow CME, whereas the later one was associated with a fast full halo CME.
The halo CME signatures observed between the Sun and Earth using white-light and scintillation images and
in situ measurements indicated the magnetic energy utilized in the expansion and propagation. The magnetic
cloud signature at the Earth confirmed the flux rope ejected at the time of filament interaction and reconnection.
