Cyclic variations in the main components of the solar large-scale magnetic field. (arXiv:2001.05433v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Obridko_V/0/1/0/all/0/1">V. N. Obridko</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Sokoloff_D/0/1/0/all/0/1">D. D. Sokoloff</a> (1 and 2), <a href="http://arxiv.org/find/astro-ph/1/au:+Shelting_B/0/1/0/all/0/1">B. D. Shelting</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Shibalova_A/0/1/0/all/0/1">A. S. Shibalova</a> (1 and 2), <a href="http://arxiv.org/find/astro-ph/1/au:+Livshits_I/0/1/0/all/0/1">I. M. Livshits</a> (1 and 3) ((1) IZMIRAN, Troitsk, Moscow, Russia, (2) Department of Physics, Moscow State University, Moscow, Russia, (3) Sternberg State Astronomical Institute, Lomonosov Moscow State University, Moscow, Russia)
We considered variations the dipole and the quadrupole components of the
solar large-scale magnetic field. Both the axial and the equatorial dipoles
exhibit a systematic decrease in the past four cycles in accordance with the
general decrease of solar activity. The transition of the pole of a dipole from
the polar region to mid latitudes occurs rather quickly, so that the longitude
of the pole changes little. With time, however, this inclined dipole region
shifts to larger longitudes, which suggests an acceleration of the dipole
rotation. The mean rotation rate exceeds the Carrington velocity by 0.6%. The
behavior of the quadrupole differs dramatically. Its decrease over last four
cycles was much smaller than that of the dipole moment. The ratio of the
quadrupole and dipole moments has increased for four cycles more than twice in
contrast to the sunspot numbers, which displayed a twofold decrease for the
same time interval. What about quadrupole rotation, the mean longitude of the
poles of one sign decreased by 600 degrees over four cycles, which suggests
that the mean rotation rate was lower than the Carrington velocity by 0.28%. We
do not see however any conclusive evidence that, in the period under
discussion, a mode of quadrupole symmetry was excited on the Sun along with the
dipole mode.
We considered variations the dipole and the quadrupole components of the
solar large-scale magnetic field. Both the axial and the equatorial dipoles
exhibit a systematic decrease in the past four cycles in accordance with the
general decrease of solar activity. The transition of the pole of a dipole from
the polar region to mid latitudes occurs rather quickly, so that the longitude
of the pole changes little. With time, however, this inclined dipole region
shifts to larger longitudes, which suggests an acceleration of the dipole
rotation. The mean rotation rate exceeds the Carrington velocity by 0.6%. The
behavior of the quadrupole differs dramatically. Its decrease over last four
cycles was much smaller than that of the dipole moment. The ratio of the
quadrupole and dipole moments has increased for four cycles more than twice in
contrast to the sunspot numbers, which displayed a twofold decrease for the
same time interval. What about quadrupole rotation, the mean longitude of the
poles of one sign decreased by 600 degrees over four cycles, which suggests
that the mean rotation rate was lower than the Carrington velocity by 0.28%. We
do not see however any conclusive evidence that, in the period under
discussion, a mode of quadrupole symmetry was excited on the Sun along with the
dipole mode.
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