How to infer the Sun's global magnetic field using the Hanle effect
Abstract
We present a different approach to determine the characteristics of the global magnetic field of the Sun based on the study of the Hanle signals. The Hanle effect of a stellar dipole produces a surface asymmetric pattern of linear polarization that depends on the strength and geometry of this global field. Moreover, if the dipole is misaligned with respect to the rotation, the Hanle signals are modulated following the rotational period. We explore the possibility to retrieve those characteristics by comparing the computed theoretical signatures with actual observations. We show that this is possible, in the case of the Sr I line of the Sun, provided that the polarimetric sensitivity is of the order or below 10-5-10-6. The inference can be done either using the maps of resolved signals, in particular the spread of values obtained along different directions on the stellar disc, or using the disc-integrated signals.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 2017
- DOI:
- 10.1093/mnras/stw3044
- Bibcode:
- 2017MNRAS.465.4414V
- Keywords:
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- magnetic fields;
- techniques: polarimetric;
- Sun: magnetic fields;
- Sun: photosphere