E-Print Archive

There are 3950 abstracts currently viewable.


Search:

Advanced Search
Options
Main Page Add New E-Print Submitter
Information
Feedback
News Help/FAQ About Preferences
Manage Key Phrase
Notification
Subject will be restored when possible  

Dibyendu Nandi   Submitted: 2008-04-03 15:30

Twist is a component of magnetic helicity that describes the wrapping of magnetic field lines about the axis of a solar active region flux tube. Recent studies point out that in addition to governing the energetics of solar active regions, twisted flux tubes may play an important role in triggering eruptive flares and coronal mass ejections via the magnetohydrodynamic kink instability mechanism. Therefore, accurate, quantitative determination of twist is important. The most widely used technique till-date for measuring twist is based on the force-free-field equation. However, the latter's applicability is questionable at the photospheric layer, which is known not to be force-free and where routine vector magnetic field observations are made. Here, we present a new flux-tube-fitting technique for measuring the twist of solar active region magnetic fields that does not rely on the force-free-field equation. We also discuss an application of this technique that can be used to determine the susceptibility of solar active region flux tubes to the kink instability. This new method is applicable to photospheric, chromospheric and coronal magnetograms and can scale up to high spatial resolutions. Therefore, we envisage that it will be useful for studying active region sub-structures from high resolution data expected in the future.

Authors: Dibyendu Nandy, Adam Calhoun, Jessica Windschitl and M.G. Linton
Projects: None

Publication Status: Submitted to ApJL
Last Modified: 2008-09-23 21:11
Go to main E-Print page  Edit Entry  Download Preprint  Submitter's Homepage Delete Entry 

Subject will be restored when possible  

Dibyendu Nandi   Submitted: 2008-04-03 15:29

Twist is a component of magnetic helicity that describes the wrapping of mag-netic field lines about the axis of a solar active region flux tube. Recent studies point out that in addition to governing the energetics of solar active regions, twisted flux tubes may play an important role in triggering eruptive flares and coronal mass ejections via the magnetohydrodynamic kink instability mechanism. Therefore, accurate, quantitative determination of twist is important. The most widely used technique till-date for measuring twist is based on the force-free-field equation. However, the latter's applicability is questionable at the photospheric layer, which is known not to be force-free and where routine vector magnetic field observations are made. Here, we present a new flux-tube-fitting technique for measuring the twist of solar active region magnetic fields that does not rely on the force-free-field equation. We also discuss an application of this technique that can be used to determine the susceptibility of solar active region flux tubes to the kink instability. This new method is applicable to photospheric, chromospheric and coronal magnetograms and can scale up to high spatial resolutions. Therefore, we envisage that it will be useful for studying active region sub-structures from high resolution data expected in the future.

Authors: Dibyendu Nandy, Adam Calhoun, Jessica Windschitl and M.G. Linton
Projects: None

Publication Status: Submitted to ApJL
Last Modified: 2008-09-23 21:11
Go to main E-Print page  Edit Entry  Download Preprint  Submitter's Homepage Delete Entry 


Key
Go to main E-Print pageGo to main E-Print page.
Download PreprintDownload Preprint.
Submitter's HomepageSubmitters Homepage.
Edit EntryEdit Entry.
Delete AbstractDelete abstract.

Abstracts by Author
Subject will be restored when possible
Subject will be restored when possible

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



© 2003 Solar Physics Group - Montana State University