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Issue A&A
Volume 413, Number 2, January II 2004
Page(s) L11 - L14
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20034636



A&A 413, L11-L14 (2004)
DOI: 10.1051/0004-6361:20034636

Letter

Constraints on the heliospheric magnetic field variation during the Maunder Minimum from cosmic ray modulation modelling

K. Scherer1 and H. Fichtner2

1  Institut für Astrophysik und Extraterrestrische Forschung der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
    e-mail: kscherer@astro.uni-bonn.de
2  Institut für Theoretische Physik IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, 44780 Bochum, Germany
    e-mail: hf@tp4.rub.de

(Received 6 October 2003 / Accepted 24 November 2003 )

Abstract
Using a dynamic multifluid model of the global heliosphere (Bonn model) we found, that the variation of the heliospheric interface and the corresponding cosmic ray modulation can not be made responsible for the increase of the mean cosmic ray flux during the Maunder Minimum. This is because the diffusion coefficients of cosmic rays required to simulate their flux increase need an "intrinsic" time variation, i.e. one that can be attributed to the solar or heliospheric magnetic field, thus, to the solar dynamo. Our study of the diffusion coefficients constrains the decrease in the strength of the solar magnetic field during the Maunder Minimum to about a factor of 4.


Key words: cosmogenic isotopes -- cosmic ray modulation -- Maunder Minimum -- heliospheric magnetic field -- solar dynamo

Offprint request: K. Scherer, kscherer@astro.uni-bonn.de

SIMBAD Objects in preparation



© ESO 2004


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