Abstract
This paper describes the weakly nonlinear behaviour of a dynamo driven by rotating convection in the form of two-dimensional rolls. The linear problem is separable and the onset of dynamo action occurs at small wavenumbers m with a growth rate proportional to m2. In the weakly nonlinear regime a band of wavenumbers is unstable, and an amplitude equation is obtained describing the nonlinear interactions between modes of different wavenumber. The behaviour of the amplitude equation shows an inverse cascade, with the mode of fastest growth rate giving way to solutions with longer and longer wavelength, over long timescales.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsPreview
Unable to display preview. Download preview PDF.
References
Chandrasekhar, S. (1961) Hydrodynamic and hydromagnetic stability. Oxford.
Chapman, C.J. and Proctor, M.R.E. (1980) Nonlinear Rayleigh-Benard convection between poorly conducting boundaries, J. Fluid. Mech., 101, 759–782.
Childress, S. and Soward, A.M. (1972) Convection-driven hydrodynamic dynamo, Phys. Rev. Lett., 29, 837–839.
Cox, S.M. and Matthews, P.C. (2000) Exponential time differencing for stiff systems, J. Comp. Phys., submitted.
Galanti, B., Sulem, P.L. and Gilbert, A.D. (1991) Inverse cascades and time-dependent dynamos in MHD flows, Physica D, 47, 416–426.
Gilbert, A.D. and Sulem, P.L. (1990) On inverse cascades in alpha effect dynamos, Geophys. Astrophys. Fluid Dynamics, 51, 243–261.
Matthews, P.C. (1999) Dynamo action in simple convective flows, Proc. R. Soc. Lond. A, 455, 1829–1840.
Matthews, P.C. and Cox, S.M. (2000) Pattern formation with a conservation law, Nonlinearity, 13, 1293–1320.
Novick-Cohen, A. and Segel, L.A. (1984) Nonlinear aspects of the Cahn-Hilliard equation, Physica D, 10, 277–298.
Roberts, G.O. (1972) Dynamo action of fluid motions with two-dimensional periodicity, Phil Trans. R. Soc. Lond. A, 271, 411–454.
Soward, A.M. (1974) A convection-driven dynamo, Phil. Trans. R. Soc. Lond. A, 275, 611–630.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2001 Springer Science+Business Media Dordrecht
About this chapter
Cite this chapter
Matthews, P. (2001). Convection-Driven Dynamos, Amplitude Equations and Large-Scale Fields. In: Chossat, P., Ambruster, D., Oprea, I. (eds) Dynamo and Dynamics, a Mathematical Challenge. NATO Science Series, vol 26. Springer, Dordrecht. https://doi.org/10.1007/978-94-010-0788-7_42
Download citation
DOI: https://doi.org/10.1007/978-94-010-0788-7_42
Publisher Name: Springer, Dordrecht
Print ISBN: 978-0-7923-7070-3
Online ISBN: 978-94-010-0788-7
eBook Packages: Springer Book Archive