| Issue |
A&A
Volume 647, March 2021
|
|
|---|---|---|
| Article Number | A60 | |
| Number of page(s) | 18 | |
| Section | Catalogs and data | |
| DOI | https://doi.org/10.1051/0004-6361/202038868 | |
| Published online | 09 March 2021 | |
24 synoptic maps of average magnetic field in 296 prominences measured by the Hanle effect during the ascending phase of solar cycle 21⋆
1
LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, 5 Place Jules Janssen, 92190 Meudon, France
e-mail: V.Bommier@obspm.fr
2
, 65 Rue du Château, 92100 Boulogne-Billancourt, France
3
LERMA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, 5 Place Jules Janssen, 92190 Meudon, France
Received:
8
July
2020
Accepted:
7
January
2021
Aims. We present 24 synoptic maps of solar filaments, in which the average unambiguous magnetic field vectors of 296 prominences were determined with Pic-du-Midi observations between 1974 and 1982. This was the ascending phase of cycle 21.
Methods. The magnetic field was determined by interpreting the Hanle effect, which is observed in the He I D3 line. Previous results for the prominence field polarity and prominence chirality were applied to solve the fundamental ambiguity. The measurements were averaged in each prominence for accuracy reasons.
Results. The result is twofold. First, alternating field directions can be observed from one neutral line to the next. Second, a general field alignment is found along a solar north-south field that is distorted by the differential rotation effect.
Key words: magnetic fields / polarization / Sun: magnetic fields / Sun: filaments, prominences
The 296 prominences solar coordinates and magnetic field vector data are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/647/A60
© V. Bommier et al. 2021
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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