Spectropolarimetric analysis of an active region filament. I. Magnetic and dynamical properties from single component inversions
Abstract
Aims: The determination of the magnetic filed vector in solar filaments is made possible by interpreting the Hanle and Zeeman effects in suitable chromospheric spectral lines like those of the He I multiplet at 10 830 Å. We study the vector magnetic field of an active region filament (NOAA 12087).
Methods: Spectropolarimetric data of this active region was acquired with the GRIS instrument at the GREGOR telescope and studied simultaneously in the chromosphere with the He I 10 830 Å multiplet and in the photosphere Si I 10 827 Å line. As has been done in previous studies, only a single-component model was used to infer the magnetic properties of the filament. The results are put into a solar context with the help of the Solar Dynamic Observatory images.
Results: Some results clearly point out that a more complex inversion had to be performed. First, the Stokes V map of He I does not show a clear signature of the presence of the filament. Second, the local azimuth map follows the same pattern as Stokes V; it appears that polarity of Stokes V is conditioning the inference to very different magnetic fields even with similar linear polarization signals. This indication suggests that the Stokes V could be dominated from below by the magnetic field coming from the active region, and not from the filament itself. This evidence, and others, will be analyzed in depth and a more complex inversion will be attempted in the second part of this series.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 2019
- DOI:
- 10.1051/0004-6361/201834790
- arXiv:
- arXiv:1904.09593
- Bibcode:
- 2019A&A...625A.128D
- Keywords:
-
- Sun: filaments;
- prominences;
- Sun: chromosphere;
- Sun: magnetic fields;
- Sun: infrared;
- Sun: evolution;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 18 pages, 19 figures, accepted for publication in A&