Hydromagnetic dynamos in rotating non-uniformly stratified spherical fluid shells in dependence on the Rayleigh number

Ján Šimkanin (1) , Pavel Hejda (1) , Dana Saxonbergová (1)

1 CAS - Czech Academy of Sciences [Prague]

We present an investigation of dynamo in non-uniformly stratified spherical shells dependent on the Rayleigh number and thickness of a stable stratified sub-shell with emphasis on the case characterized by the identical thicknesses of both sub-shells. Our previous study of rotating convection showed that this case of stratification is a typical extreme case. However, the dynamo action in the shell characterized by the identical thicknesses of both subshells is not the typical extreme case. The generated magnetic field is close to the cases of uniform stratification and non-uniform one if the thickness of a stable stratified sub-shell is smaller than the thickness of an unstable stratified sub-shell. Similarly as in the case of rotating convection also in the case of dynamo action the multilayer convection ("teleconvection") is not developed in such a case because of the significant amount of stable stratification.

Mots clés: Hydromagnetic dynamo; Non-uniform stratification; Penetrative convection; Rayleigh number

Domaines: Sciences de la Terre

Ján Šimkanin, Pavel Hejda, Dana Saxonbergová. Hydromagnetic dynamos in rotating non-uniformly stratified spherical fluid shells in dependence on the Rayleigh number. Physics of the Earth and Planetary Interiors, 2011, 185 (3-4), pp.100. ⟨10.1016/j.pepi.2011.02.002⟩. ⟨hal-00735848⟩