Onset of Inertial Magnetoconvection in Rotating Fluid Spheres

Magneto-inertial convection in rotating fluid spheres

The onset of convection in the form of magneto-inertial waves in a rotating fluid sphere permeated by a constant axial electric current is studied through a perturbation analysis. Explicit expressions for the dependence of the Rayleigh number on the azimuthal wavenumber are derived in the limit of high thermal diffusivity. Results for the cases of thermally infinitely conducting and of nearly t...

Anisotropic turbulence in rotating magnetoconvection

Numerical simulations of the 3D MHD-equations that describe rotating magnetoconvection in a Cartesian box have been performed using the code NIRVANA. The characteristics of large-scale quantities like the turbulence intensity and the turbulent heat flux that are caused by the average action of the small-scale fluctuations are computed directly from the fluctuating primitive variables. and the e...

Rotating Magnetoconvection with Magnetostrophic Balance

The linear theory for the onset of convection in a rotating layer with an imposed vertical magnetic field is studied for large Taylor (Ta) and Chandrasekhar (Q) numbers. The velocity and magnetic field perturbations are in magnetostrophic balance. For small values of σ = ν/κ and ζ = η/κ, where ν, κ and η are the kinematic viscosity, and thermal and ohmic diffusivities, three oscillatory modes a...

Onset of Turbulence in a Rotating Fluid

Geodynamo α-effect derived from box simulations of rotating magnetoconvection

The equations for fully compressible rotating magnetoconvection are numerically solved in a Cartesian box assuming conditions roughly suitable for the geodynamo. The mean electromotive force describing the generation of mean magnetic flux by convective turbulence in the rotating fluid is directly calculated from the simulations, and the corresponding α-coefficients are derived. Due to the very ...