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Predicting solar ‘climate’ by assimilating magnetic data into a flux‐transport dynamo
Author(s) -
Dikpati M.
Publication year - 2007
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.200710885
Subject(s) - dynamo , solar dynamo , physics , differential rotation , magnetic flux , dynamo theory , solar cycle , earth's magnetic field , flux (metallurgy) , meridional flow , magnetic field , atmospheric sciences , geophysics , astrophysics , zonal and meridional , solar wind , materials science , quantum mechanics , metallurgy
Observational and theoretical knowledge about global‐scale solar dynamo ingredients have reached the stage that it is possible to calibrate a flux‐transport dynamo for the Sun by adjusting only a few tunable parameters. The important ingredients in this class of model are differential rotation (Omega‐effect), helical turbulence (alpha‐effect), meridional circulation and turbulent diffusion. The meridional circulation works as a conveyor belt and governs the dynamo cycle period. Meridional circulation and magnetic diffusivity together govern the memory of the Sun's past magnetic fields. After describing the physical processes involved in a flux‐transport dynamo, we will show that a predictive tool can be built from it to predict mean solar cycle features by assimilating magnetic field data from previous cycles. We will discuss the theoretical and observational connections among various predictors, such as dynamo‐generated toroidal flux integral, cross‐equatorial flux, polar fields and geomagnetic indices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)