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 thermally insulating boundaries are obtained.Comment: 10 pages, 5 figures, to be submitted for publicatio
