Brigitte Schmieder (Observatoire de Paris): Magnetic field vectors in filament channels

Fredagskollokvium

Abstract.

The problem of formation of filament is still alive. Recent high spatial resolution H-alpha observations (i.e. SST at LaPalma) show the importance of the dynamic nature of filament plasma. This could suggest that filaments are formed by injection. Theoretical magnetohydrodynamic 3D models predicted shallow dips in magnetic field lines supporting filaments. In these dips condensation is expected due thermal instabilities. It is important to observe the orientation of the magnetic field lines near the filament feet (i.e.barbs) to check which mechanism is the more efficient.

I will present recent THEMIS/MTR (Tenerife) observations of the magnetic field vector in filament channels where weak polarities have been identified. These polarities are important for explaining the morphology of H-alpha filaments and their barbs. The magnetic vectors indicate a concave topology (magnetic dips) in the filament channel. With a time dependent analysis the changes of filament structures have been related to magnetic changes, emergence flux as well as cancelling flux. This relationship was confirmed by a simple sequence of linear force-free models.

Publisert 12. aug. 2009 10:13 - Sist endret 15. juni 2011 13:49