Physical causes of solar cycle amplitude variability

R. H. Cameron, J. Jiang, M. Schüssler, Laurent Gizon

    Research output: Contribution to journalArticle

    Abstract

    The level of solar activity varies from cycle to cycle. This variability is probably caused by a combination of nonlinear and random effects. Based on surface flux transport simulations, we show that the observed inflows into active regions and toward the activity belts provide an important nonlinearity in the framework of Babcock-Leighton model for the solar dynamo. Inclusion of these inflows also leads to a reproduction of the observed proportionality between the open heliospheric flux during activity minima and the maximum sunspot number of the following cycle. A substantial component of the random variability of the cycle strength is associated with the cross-equatorial flux plumes that occur when large, highly tilted sunspot groups emerge close to the equator. We show that the flux transported by these events is important for the amplitude of the polar fields and open flux during activity minima. The combined action of inflows and cross-equatorial flux plumes provides an explanation for the weakness of the polar fields at the end of solar cycle 23 (and hence for the relative weakness of solar cycle 24).

    Original languageEnglish (US)
    Pages (from-to)680-688
    Number of pages9
    JournalJournal of Geophysical Research A: Space Physics
    Volume119
    Issue number2
    DOIs
    StatePublished - Feb 1 2014

    Fingerprint

    solar cycles
    solar cycle
    inflow
    sunspot
    causes
    plume
    cycles
    surface flux
    sunspots
    solar activity
    nonlinearity
    plumes
    equators
    simulation
    inclusions

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Geophysics

    Cite this

    Physical causes of solar cycle amplitude variability. / Cameron, R. H.; Jiang, J.; Schüssler, M.; Gizon, Laurent.

    In: Journal of Geophysical Research A: Space Physics, Vol. 119, No. 2, 01.02.2014, p. 680-688.

    Research output: Contribution to journalArticle

    Cameron, R. H. ; Jiang, J. ; Schüssler, M. ; Gizon, Laurent. / Physical causes of solar cycle amplitude variability. In: Journal of Geophysical Research A: Space Physics. 2014 ; Vol. 119, No. 2. pp. 680-688.
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