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| Titel |
Topologically driven coronal dynamics – a mechanism for coronal hole jets |
| VerfasserIn |
D. A. N. Müller, S. K. Antiochos |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 26, no. 10 ; Nr. 26, no. 10 (2008-10-15), S.2967-2974 |
| Datensatznummer |
250016243
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| Publikation (Nr.) |
 copernicus.org/angeo-26-2967-2008.pdf |
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| Zusammenfassung |
| Bald patches are magnetic topologies in which the magnetic field is concave
up over part of a photospheric polarity inversion line. A bald patch topology
is believed to be the essential ingredient for filament channels and is often
found in extrapolations of the observed photospheric field. Using an analytic
source-surface model to calculate the magnetic topology of a small bipolar
region embedded in a global magnetic dipole field, we demonstrate that
although common in closed-field regions close to the solar equator, bald
patches are unlikely to occur in the open-field topology of a coronal hole.
Our results give rise to the following question: What happens to a bald patch
topology when the surrounding field lines open up? This would be the case
when a bald patch moves into a coronal hole, or when a coronal hole forms in
an area that encompasses a bald patch. Our magnetostatic models show that, in
this case, the bald patch topology almost invariably transforms into a null
point topology with a spine and a fan. We argue that the time-dependent
evolution of this scenario will be very dynamic since the change from a bald
patch to null point topology cannot occur via a simple ideal evolution in the
corona. We discuss the implications of these findings for recent Hinode XRT
observations of coronal hole jets and give an outline of planned
time-dependent 3-D MHD simulations to fully assess this scenario. |
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