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Can we look inside a dynamo?
Author(s) -
Stefani F.,
Gerbeth G.
Publication year - 2000
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 - 10.1002/1521-3994(200011)321:4<235::aid-asna235>3.0.co;2-9
Subject(s) - dynamo , dynamo theory , physics , inverse , eigenvalues and eigenvectors , solar dynamo , magnetic field , inverse problem , field (mathematics) , statistical physics , quantum electrodynamics , classical mechanics , mathematical analysis , mathematics , quantum mechanics , geometry , pure mathematics
For a simple spherically symmetric mean‐field dynamo model we investigate the possibility of determining the radial dependence of the coefficient α. Growth rates for different magnetic field modes are assumed to be known by measurement. An evolutionary strategy (ES) is used for the solution of the inverse problem. Numerically, we find quite different α‐profiles giving nearly the same eigenvalues. The ES is also applied to find functions α( r ) yielding zero growth rates for the lowest four magnetic field modes. Additionally, a slight modification of the ES is utilized for an “energetic” optimization of α 2 ‐dynamos. The consequences of our findings for inverse dynamo theory and for the design of future dynamo experiments are discussed.