Spherical Single-Roll Dynamos at Large Magnetic Reynolds Numbers
David Ivers and Henrik Latter
The asymptotic theory of Gilbert and Ponty (2000) for axisymmetric spherical roll flow dynamos at large magnetic Reynolds \Rm numbers is compared to the numerical eigen-solutions for two flows. The flows are the s01t01 of Dudley and James(1989) and an s01t01t03 modification of it. The numerical method uses the hybrid vector spherical harmonic technique of Ivers and Phillips (2003) with fourth-order finite-differences. Excellent agreement is in the asymptotic regime \Rm>10,000 for both the growth rate and the angular frequency. The asymptotic theory is extended to the next order.Keywords: magnetohydrodynamics, kinematic dynamos, asymptotic theory.
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