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| Paper: |
Solar Cycle Variations of the Second Solar Spectrum |
| Volume: |
489, Solar Polarization 7 |
| Page: |
167 |
| Authors: |
Bianda, M.; Ramelli, R.; Gisler, D.; Stenflo, J. O. |
| Abstract: |
The average strength of the spatially unresolved turbulent magnetic
field in the Sun's photosphere can be measured with the Hanle
effect. The possible variations of this average value over time scales
of a solar cycle is the topic of an ongoing synoptic program at IRSOL
that was started in 2008. The scattering polarization of C2
molecular lines
around 5140 Å is regularly measured, typically once per
month. These lines allow the application of the differential Hanle
effect to determine the turbulent field strength. Here we report about
the behavior of the determined field strength during the beginning active phase
of the solar cycle and about our intention to start a new
synoptic program based on the Hanle effect in the Sr I 4607 Å
line, with which turbulent field strengths are found that are an order
of magnitude larger than those determined with the molecular C2
lines. These synoptic programs allow us to explore the nature of the magnetic
fields at the small-scale end of the
magnetic scale spectrum and to determine the possible role of a local dynamo for the
generation of these fields. |
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