Polarization effects in RATAN-600 solar observations in the “Southern sector with a flat reflector” mode

• Published in: Astrophysical bulletin 2012, Vol.67 (1), p.90-114
• Main Authors: Opeikina, L. V., Majorova, E. K., Korzhavin, A. N.
• Format: Article
• Language: English
• Subjects: Algorithms; Antennas; Astronomy; Astrophysics and Cosmology; Channels; Computation; Computer simulation; Mathematical models; Physics; Physics and Astronomy; Reflectors; Space telescopes
• ISSN: 1990-3413; 1990-3421
• DOI: 10.1134/S1990341312010099

We report the results of numerical simulations of the instrumental signal in the Stokes V channel of circular polarization as observed by RATAN-600 radio telescope operating in the “Southern sector with a flat reflector” mode. Our simulations are based on an improved algorithm of the beam pattern computation that takes into account diffraction in the space between the telescope mirrors. The computations cover a wide range of wavelengths in the case of a focused antenna and in the presence of aberrations. We analyze the structure and properties of the element M 41 of the Mueller matrix and of the parasite signal from the solar disk in various cases of the antenna irradiation. We estimate the differences between the left- and right-polarization power-beam patterns of the telescope. We report the computed M 11 and M 41 elements for the case of observation of the right- and left-polarized radiation at different points of the focal line of the secondary mirror, and analyze their variations as a function of a number of parameters, including, in particular, the shift applied to correct the displacement of scans.