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Title: The mean tilt of sunspot bipolar regions: Theory, simulations and comparison with observations
Authors: Kleeorin, N.
Safiullin, N.
Kuzanyan, K.
Rogachevskii, I.
Tlatov, A.
Porshnev, S.
Issue Date: 2020
Publisher: Oxford University Press
Citation: The mean tilt of sunspot bipolar regions: Theory, simulations and comparison with observations / N. Kleeorin, N. Safiullin, K. Kuzanyan, et al. — DOI 10.1093/mnras/staa1047 // Monthly Notices of the Royal Astronomical Society. — 2020. — Vol. 495. — Iss. 1. — P. 238-248.
Abstract: A theory of the mean tilt of sunspot bipolar regions (the angle between a line connecting the leading and following sunspots and the solar equator) is developed. A mechanism of formation of the mean tilt is related to the effect of the Coriolis force on meso-scale motions of super-granular convection and large-scale meridional circulation. The balance between the Coriolis force and the Lorentz force (the magnetic tension) determines an additional contribution caused by the large-scale magnetic field to the mean tilt of the sunspot bipolar regions at low latitudes. The latitudinal dependence of the solar differential rotation affects the mean tilt, which can explain deviations from Joy’s law for the sunspot bipolar regions at high latitudes. The theoretical results obtained and the results from numerical simulations based on the nonlinear mean-field dynamo theory, which takes into account conservation of the total magnetic helicity and the budget equation for the evolution of the Wolf number density, are in agreement with observational data of the mean tilt of sunspot bipolar regions over individual solar cycles 15–24. © 2020 The Author(s).
Keywords: DYNAMO
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85095175555
PURE ID: 13176233
ISSN: 358711
DOI: 10.1093/mnras/staa1047
metadata.dc.description.sponsorship: The work of KK and NS was supported in part by a grant from the Russian Science Foundation (grant RNF 18-12-00131) at the Crimean Astrophysical Observatory. AT would like to acknowledge support from RFBR grant 18-02-00098 for the observational data analysis. NK, KK, IR acknowledge the hospitality of NORDITA.
RSCF project card: 18-12-00131
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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