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Scaling laws for convective dynamos
We study magnetic dynamos in developed (turbulent) convection. The scaling laws for the strength of the induced magnetic field measured by the Hartmann and the Nusselt number (measuring the superadiabatic convective heat flux) number with the Rayleigh number (measuring the strength of the driving force) are found. Three cases are studied - two of them covering the range of parameters achievable in numerical and possible future laboratory experiments and the third corresponding to the parameter regime for the Earth’s liquid outer core. We find, that at least in the case of Boussinesq dynamos the presence of induced magnetic field tends to decrease (or leave unchanged) the order of magnitude of the convective heat flux in the system. The effect of compressibility is also studied; it is found to be more complex and it typically decreases the convective heat flux.Author(s):
Krzysztof Mizerski
Department of Magnetism, Institute of Geophysics, Polish Academy of Sciences, ul. Ksiecia Janusza 64, 01-452 Warsaw
Poland
Chris Jones
Department of Applied Mathematics, University of Leeds, Woodhouse Lane, LS2 9JT
United Kingdom