Abstract
A study of the circular polarization structure of solar active regions has been made from data obtained at 9.5 mm wavelength, using the 85 ft reflector and polarimeter at the Naval Research Laboratory Maryland Point Observatory. The angular resolution of the telescope at this wavelength is 1′.6. All important active regions observed at 9.5 mm are bipolar in nature, the degree of polarization is about the same for both right and left circular components and it ranges up to about 4%. These oppositely polarized components correspond with the Mt. Wilson magnetic regions of opposite polarity; the line of zero polarization delineates clearly the neutral line between the regions of opposite polarity on magnetograms. Unipolar regions in magnetograms also show up as unipolar regions at 9.5 mm. Magnetic fields as low as 5–10 G on magnetograms manifest as distinctly polarized regions on 9.5 mm maps. A line of zero polarization seems to delineate the extent of ‘absorption features’ observed at 9.5 mm in coincidence with Hα dark filaments.
Similar content being viewed by others
References
Kundu, M. R.: 1965, Solar Radio Astronomy, John Wiley - Interscience Publishers, p. 234
Kundu, M. R.: 1970, Solar Phys. 13, 348.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kundu, M.R., McCullough, T.P. Polarization of solar active regions at 9.5 mm wavelength. Sol Phys 24, 133–141 (1972). https://doi.org/10.1007/BF00231091
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00231091