Redshifted transition region lines explained
Abstract
The discovery of differential redshift between transition region and chromospheric line emissions, both in the spectra of late-type stars and in the solar spectra has been a puzzle for more than a decade. The fact that the solar observations appear to be inconsistent with a continuous downflow calls for another interpretation. We propose that this pervasive redshift observed in transition region spectral lines is caused by conduction modified MHD waves propagating along the magnetic field lines from the corona towards the chromosphere. The waves are assumed generated in the corona by nanoflares, i.e.by an episodic heating mechanism. The calculations for acoustic waves show line profiles with many of the same characteristics as the observations.
- Publication:
-
Advances in Space Research
- Pub Date:
- April 1994
- DOI:
- 10.1016/0273-1177(94)90161-9
- Bibcode:
- 1994AdSpR..14d..57H
- Keywords:
-
- Chromosphere;
- Emission Spectra;
- Late Stars;
- Line Spectra;
- Red Shift;
- Solar Spectra;
- Magnetohydrodynamic Waves;
- Plasma Dynamics;
- Plasma Heating;
- Solar Magnetic Field;
- Wave Propagation;
- Astrophysics