Convection within the inner‐core and thermal implications

Abstract

Estimation of the Rayleigh numbers of the inner‐core leads to the conclusion that, even with low internal heating rates, this region of the Earth is convecting. This work presents an axisymmetrical model able to investigate convection in a sphere and its applications to the Earth's inner‐core. Rayleigh numbers ranging from the critical (onset of the convection) to ten thousand times the critical have been explored. The thermal implications of a convecting inner‐core have been pointed out: in all the cases the temperature profiles are very close to the adiabat, leading to the possibility of a partially molten regions in the inner‐core. Indeed, the most important effects appear in the first tens of kilometers, just below the inner‐core surface and could be at the origin of the low quality factors Qα and Qβ revealed by seismological studies.