Abstract
Solar flares and prominence eruptions are considered as sources of
interplanetary and
geomagnetic storms. An H alpha filament disappearance
and a following big flare whose importance was 3B in H alpha and M4 in
GOES X-ray class
occurred near the solar disc center on February 20, 1994. This event
caused a strong geomagnetic
storm. The event was fully observed in H alpha, H alpha+0.8 AA and H
alpha-0.8 AA with the
Flare Monitoring Telescope at Hida Observatory, Kyoto University, and in
17GHz continuum with
the Nobeyama Radio Heliograph.
The H alpha, H alpha+0.8 AA and H
alpha-0.8 AA images gave
us dynamical features of the disappearing filament at the initial stage
of the eruption. The 17GHz
data revealed much faster motions of the erupting filament across the
solar disc and even outside
of the solar limb, since it is insensitive to line-of-sight motion.
Combining these data, we
reconstruct a three-dimensional model of the filament eruption.