E-Print Archive

There are 4594 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
The structure and evolution of a sigmoidal active region View all abstracts by submitter

Sarah Gibson   Submitted: 2002-10-04 14:43

Solar coronal sigmoidal active regions have been shown to be precursors to some coronal mass ejections (CMEs). Sigmoids, or ``S''-shaped structures, may be indicators of twisted or helical magnetic structures, having an increased likelihood of eruption. We present here an analysis of a sigmoidal region's 3-d structure and how it evolves in relation to its eruptive dynamics. We use data taken during a recent study of a sigmoidal active region passing across the solar disk (an element of the third ``Whole Sun Month'' campaign). While S-shaped structures are generally observed in soft X-ray (SXR) emission, the observations we present demonstrate their visibility at a range of wavelengths including those showing an associated sigmoidal filament. We examine the relationship between the S-shaped structures seen in SXR and those seen in cooler lines in order to probe the sigmoidal region's 3-d density and temperature structure. We also consider magnetic field observations and extrapolations in relation to these coronal structures. We present an interpretation of the disk passage of the sigmoidal region, in terms of a twisted magnetic flux rope that emerges into and equilibrates with overlying coronal magnetic field structures, which explains many of the key observed aspects of the region's structure and evolution. In particular, the evolving flux rope interpretation provides insight into why and how the region moves between active and quiescent phases, how the region's sigmoidicity is maintained during its evolution, and under what circumstances sigmoidal structures are apparent at a range of wavelengths.

Authors: S. E. Gibson, L. Fletcher, G. Del Zanna, C. D. Pike, H. E. Mason,C. H. Mandrini, P. Demoulin, H. Gilbert, J. Burkepile, T. Holzer, D. Alexander, Y. Liu, N. Nitta, J. Qiu, B. Schmieder, and B. J. Thompson
Projects: None

Publication Status: ApJ, 574, 1021, 2002
Last Modified: 2006-01-12 09:43
Go to main E-Print page  The EIT coil-like structure in the March 20, 2000 eruptive prominence  RHESSI observations of size scales of solar hard X-ray sources  Edit Entry  Download Preprint  Submitter's Homepage Delete Entry 

Go to main E-Print pageGo to main E-Print page.
Previous AbstractPrevious Abstract.
Next AbstractNext Abstract.
Download PreprintDownload Preprint.
Submitter's HomepageSubmitters Homepage.
Edit EntryEdit Entry.
View All Abstracts By SubmitterView all abstracts by submitter.
Delete AbstractDelete abstract.

Latest Entries
Repeated Type III Burst Groups Associated with a B-Class Flare and a Narrow-Width CME
Separating the effects of earthside and far side solar events. A case study.
Deciphering The Slow-rise Precursor of a Major Coronal Mass Ejection
Three-dimensional Turbulent Reconnection within Solar Flare Current Sheet
Sequential Remote Brightenings and Co-spatial Fast Downflows during Two Successive Flares
A Model for Confined Solar Eruptions Including External Reconnection
The eruption of a magnetic flux rope observed by Solar Orbiter and Parker Solar Probe
Comprehensive radiative MHD simulations of eruptive flares above collisional polarity inversion lines
An Anisotropic Density Turbulence Model from the Sun to 1 au Derived From Radio Observations
Comparison of damping models for kink oscillations of coronal loops
On the three-dimensional relation between the coronal dimming, erupting filament and CME. Case study of the 28 October 2021 X1.0 event
Polarisation of decayless kink oscillations of solar coronal loops
CME Propagation Through the Heliosphere: Status and Future of Observations and Model Development
30-min Decayless Kink Oscillations in a Very Long Bundle of Solar Coronal Plasma Loops
The Role of High-Frequency Transverse Oscillations in Coronal Heating
ARTop: an open-source tool for measuring Active Region Topology at the solar photosphere
Spectral Observations and Modeling of a Solar White-light Flare Observed by CHASE
New cases of super-flares on slowly rotating solar-type stars and large amplitude super-flares in G- and M-type main-sequence stars
Constraints on the variable nature of the slow solar wind with the Wide-Field Imager on board the Parker Solar Probe
Prediction of short stellar activity cycles using derived and established empirical relations between activity and rotation periods

Related Pages
MSU Solar Physics.
Max Millennium Science Mail Archive.
Max Millennium Message of the Day Mail Archive.
Max Millennium Flare Catalog

Archive Maintainer
Alisdair Davey

© 2000-2020 Solar Physics Group - Montana State University