Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000apj...545.1089l&link_type=abstract
The Astrophysical Journal, Volume 545, Issue 2, pp. 1089-1100.
Astronomy and Astrophysics
Astronomy
61
Magnetohydrodynamics: Mhd, Sun: Activity, Sun: Corona, Sun: Magnetic Fields
Scientific paper
Observations have shown that active region flux tubes often emerge in a twisted state and that the active region formed has magnetic helicity of the same sense as the flux tube that forms it. Separate theoretical models have been developed for coronal magnetic fields with helicity and for flux tubes with twist. Here we present a dynamical model that connects a twisted subphotospheric flux tube to a force-free coronal field. With this model it is possible to explore the emergence of a flux tube into the corona and its effect on both the coronal field and the subphotospheric flux tube. In particular, the model shows that only a fraction of the current carried by the twisted flux tube will pass into the corona. As a consequence of this ``mismatch,'' a torsional Alfvén wave is launched downward along the flux tube at the instant of emergence. As the flux tube continues to emerge, the helicity of the coronal field increases owing to rotation of the footpoints. Our model predicts that the level of rotation will depend upon the rapidity of flux emergence. After this transient period the helicity of the active region will reflect the twist in its parent tube.
Longcope Dana Warfield
Welsch Brian Thomas
No associations
LandOfFree
A Model for the Emergence of a Twisted Magnetic Flux Tube does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A Model for the Emergence of a Twisted Magnetic Flux Tube, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Model for the Emergence of a Twisted Magnetic Flux Tube will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1731196