Asymptotic behaviour of rotating convection-driven dynamos in the plane layer geometry

نویسندگان

چکیده

Dynamos driven by rotating convection in the plane layer geometry are investigated numerically for a range of Ekman number ( $E$ ), magnetic Prandtl $Pm$ ) and Rayleigh $Ra$ ). The primary purpose investigation is to compare results simulations with previously developed asymptotic theory that applicable limit rapid rotation. We find all quasi-geostrophic regime which Coriolis pressure gradient forces approximately balanced at leading order, whereas other forces, including Lorentz force, act as perturbations. Agreement between simulation output scalings energetics, flow speeds, field amplitude length scales found. transition from large-scale dynamos small-scale well described Reynolds based on small convective scale, $\widetilde {Rm}$ , preferred when {Rm} \lesssim O(1)$ . magnitude observed saturate become constant increasing number. Energy spectra show present consistent scaling $E^{1/3}$ even turbulent regime. For fixed value we viscous dissipation scale over broad ; ohmic within dynamo regime, but transitions {Rm}^{-1/2}$

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ژورنال

عنوان ژورنال: Journal of Fluid Mechanics

سال: 2022

ISSN: ['0022-1120', '1469-7645']

DOI: https://doi.org/10.1017/jfm.2022.848