Time evolution of arch filaments
Abstract
We have studied the spatial structure and the temporal evolution of the velocity in active region arch filaments. The observations were obtained with the Multichannel Double Pass Spectrograph operating in H-alpha at the Pic du Midi Observatory. Line profiles were reconstructed and monochromatic images and Doppler shift velocities were derived over a 2D FOV. Using Beckers' (1964) cloud model we derived physical parameters, in particular the line of sight velocity. The arches showed the 'classical' type of motion, with material moving towards the observer near the apex and away from the observer near the footpoints. Assuming a symmetric loop, we reconstructed the velocity vector along the arch filaments. The results are consistent with the picture where material is draining out of the filament, while the whole structure is ascending. In one case we observed changes in the geometry and the velocity vector; however, other arch filaments did not change appreciably in a time period of about 13.5 min.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1992
- Bibcode:
- 1992A&A...262..587T
- Keywords:
-
- Chromosphere;
- H Alpha Line;
- Line Shape;
- Solar Activity;
- Solar Atmosphere;
- Solar Physics;
- Stellar Evolution;
- Solar Physics