Spherical single-roll dynamos at large magnetic Reynolds numbers

Henrik Latter; David Ivers

doi:10.1063/1.3453712

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arXiv · 1006.2308

Spherical single-roll dynamos at large magnetic Reynolds numbers

Henrik Latter·David Ivers

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Abstract

This paper concerns kinematic helical dynamos in a spherical fluid body surrounded by an insulator. In particular, we examine their behaviour in the regime of large magnetic Reynolds number $\Rm$, for which dynamo action is usually concentrated upon a simple resonant stream-surface. The dynamo eigensolutions are computed numerically for two representative single-roll flows using a compact spherical harmonic decomposition and fourth-order finite-differences in radius. These solutions are then compared with the growth rates and eigenfunctions of the Gilbert and Ponty (2000) large $\Rm$ asymptotic theory. We find good agreement between the growth rates when $\Rm>10^4$, and between the eigenfunctions when $\Rm>10^5$.

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Henrik Latter, David Ivers. 2010-06-11. Spherical single-roll dynamos at large magnetic Reynolds numbers. https://doi.org/10.1063/1.3453712

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