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Evolution of Pre-Eruption Sigmoids into Post-Eruption Arcades in Suspected
CME Source Regions
Alphonse C. Sterling
There is growing evidence that S-shaped or inverse-S shaped sigmoid structures
in the soft X-ray (SXR) solar corona are the source regions of at least
some Coronal Mass Ejections (CMEs). These SXR "sigmoids" mark the
presence of non-potential magnetic "core field" structures which erupt
to form a portion of the CME. After eruption, these source regions
take the form of more nearly potential field arcades, often with
a cusp structure visible in SXRs. An understanding of the evolution
from the pre-eruption structures to the post-eruption structures is a key
element in untangling the mechanism underlying the eruption process.
In this work, we examine details of this evolution for several eruptive
events, using high cadence data from the Soft X-ray Telescope (SXT) on
Yohkoh. In particular we study the spatial relationship between the
pre-eruption sigmoid and the post-eruption arcade, considering how well
the actual cases fit the standard opening/reclosing 3D magnetic field picture
for ejective flare/CME events.
Authors: Alphonse C. Sterling, Ron L.
Address: SD50/Space Science Division
Marshall Space Flight Center
Huntsville, Alabama, 35812
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