Solar magnetic fields measurements with a magneto-optical filter

• Published in: Il nuovo cimento della Società italiana di fisica. Sezione C, Geophysics and space physics Vol. 13 C; no. 1; pp. 125 - 130
• Main Authors: Cacciani, A., Ricci, D., Rosati, P., Rhodes, E. J., Smith, E.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Legacy CDMS Compositori 01-01-1990
• Subjects: Astronomy; Diameter, figure, rotation, mass; Earth, ocean, space; Exact sciences and technology; Solar Physics; Solar system; Helioseismology; Data analysis; Solar magnetic field; Sun; Finding chart; Magnetogram
• ISSN: 0390-5551; 1826-9885
• DOI: 10.1007/BF02515781

The presence of a magnetic field at different levels inside the sun has crucial implications for helioseismology. The solar oscillation observing program carried out since 1983 at Mt. Wilson with Cacciani magneto-optical filter has recently been modified to acquire full-disk magnetograms with 2 arcsec spatial resolution. A method for the correct determination of magnetic maps which are free of contamination by velocity signal is presented. It is shown that no cross-talk exists between the Doppler and Zeeman shifts of the Na D lines, provided that instrumental polarization effects are taken into account. The observed line-of-sight photospheric field was used to map the vector field in the inner corona, above active regions, in the current free approximation.