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An asymptotic solution of a kinematic αΩ-dynamo with meridional circulation


Soward, AM and Bassom, AP and Kuzanyan, KM and Sokoloff, D, An asymptotic solution of a kinematic αΩ-dynamo with meridional circulation, Geophysical and Astrophysical Fluid Dynamics, 107, (6) pp. 667-714. ISSN 0309-1929 (2013) [Refereed Article]

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Copyright 2013 Taylor & Francis

DOI: doi:10.1080/03091929.2013.807166


Asymptotic methods are used to study a one-dimensional kinematic αΩ-Parker dynamo wave model in the limit when the strength of the αΩ-sources, as measured by the dynamo number D, is large. The model includes the influence of meridional circulation with a characteristic poleward velocity (strictly a magnetic Reynolds number) V, and builds on the earlier work of Popova and Sokoloff (Meridional circulation and dynamo waves. Astron. Nachr. 2008, 329, 766768). On increasing V, the equatorward phase velocity of the Parker dynamo wave is decreased and, when a particular value of V (say VT α D1/3) is reached, non-oscillatory solutions ensue. Though a complete analytic solution is not possible for V = VT , the nature of the transition from travelling waves to non-oscillatory solution, as the value of V varies across VT, is readily understood within the asymptotic framework. It is remarkable that such a simple one-dimensional model can illustrate the possibility of either travelling waves or non-oscillatory solutions dependent on the magnitude of the meridional circulation, a feature, which has long been known from the numerical study of the full partial differential equations governing axisymmetric αΩ-dynamos (e.g. Roberts, P.H., Kinematic dynamo models. Phil. Trans. R. Soc. Lond. A 1972, 272, 663698).

Item Details

Item Type:Refereed Article
Keywords:dynamo waves, non-oscillatory dynamos, meridional circulation, WKB-solution
Research Division:Mathematical Sciences
Research Group:Applied mathematics
Research Field:Theoretical and applied mechanics
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the mathematical sciences
UTAS Author:Bassom, AP (Professor Andrew Bassom)
ID Code:105770
Year Published:2013
Web of Science® Times Cited:4
Deposited By:Mathematics and Physics
Deposited On:2016-01-14
Last Modified:2017-11-03

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