Forward-scattering Hanle effect in the solar Ca i 4227 Å line

H. Frisch; L.S. Anusha; M. Bianda; R. Holzreuter; K.N. Nagendra; R. Ramelli; M. Sampoorna; H.N. Smitha; J.O. Stenflo

doi:10.1051/eas/1255007

All issues

Volume 55 (2012)

EAS Publications Series, 55 (2012) 59-63

Abstract

Issue		EAS Publications Series Volume 55, 2012 4th French-Chinese Meeting on Solar Physics - Understanding Solar Activity: Advances and Challenges


Page(s)		59 - 63
Section		Magnetic Field and Polarization Measurements and Theory
DOI		https://doi.org/10.1051/eas/1255007
Published online		27 June 2012

Understanding Solar Activity: Advances and Challenges
M. Faurobert, C. Fang and T. Corbard (eds)
EAS Publications Series, 55 (2012) 59-63

Forward-scattering Hanle effect in the solar Ca i 4227 Å line

H. Frisch¹, L.S. Anusha², M. Bianda³, R. Holzreuter⁴, K.N. Nagendra², R. Ramelli³, M. Sampoorna², H.N. Smitha² and J.O. Stenflo⁵^,3

¹ UNS, CNRS, OCA, Laboratoire Cassiopée, 06304 Nice Cedex 04, France
² Indian Institute of Astrophysics, Koramangala, Bangalore 560 034, India
³ Istituto Ricerche Solari Locarno, Via Patocchi, 6605 Locarno-Monti, Switzerland
⁴ MPI für Sonnenforschung, 37191 Katlenburg-Lindau, Germany
⁵ Institute of Astronomy, ETH Zürich, 8093 Zürich, Switzerland

Abstract

High sensitivity spectropolarimetric observations of the four Stokes parameters of the solar Ca i 4227 Å line have been performed in October 2010 at IRSOL with the ZIMPOL polarimeter, near the disk center, outside an active region (Bianda et al. 2011). They were analyzed in Anusha et al. 2011 with a combination of detailed radiative transfer modelling of the Hanle effect for the linear polarization and weak field Zeeman approximation for the circular polarization. This approach made possible a unique determination of the magnetic field vector at various positions along the slit of the spectrograph. A summary of the observations and of their analysis is presented here.