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Solar Full-Disk Polarization Measurement with the Fe I 15648 Å Line

Published online by Cambridge University Press:  24 July 2015

Y. Hanaoka ,
T. Sakurai  and
IRMag Group
Y. Hanaoka
Affiliation:
National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan email: [email protected]
T. Sakurai
Affiliation:
National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan email: [email protected]
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Abstract

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The near-infrared absorption line Fe I 15648 Å, which has a Landé g-factor of 3, shows a particularly large Zeeman splitting. We regularly take full-disk polarization maps of the Sun in the Fe I 15648 Å line (as well as the He I 10830 Å line) with an infrared spectropolarimeter installed at the Solar Flare Telescope of the National Astronomical Observatory of Japan (NAOJ). It is known that weak, mostly horizontal magnetic fields are ubiquitously distributed in the quiet regions of the Sun, while the strong magnetic fields are concentrated in active regions and network boundaries. The weak horizontal field has not been sufficiently investigated due to the difficulty of such observations. The polarization maps in Fe I 15648 Å show the magnetic field strength at each pixel, regardless of the filling factor, so we can easily isolate the weak horizontal field signals from strong magnetic field ones using the Stokes V profiles of the Fe I 15648 Å line. Here we present instrumental aspects and observational results of solar near-infrared full-disk polarimetry. We highlight the weak horizontal field inferred from Fe I 15648 Å.

Keywords

Sun: photosphereSun: magnetic fieldsSun: infraredTechniques: polarimetric
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 10 , Symposium S305: Polarimetry: From the Sun to Stars and Stellar Environments , December 2014 , pp. 92 - 96
Copyright
Copyright © International Astronomical Union 2015 

References

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