Evolution of the inner core of the earth: consequences for geodynamo

Abstract

Using models of the Earth's core evolution and the length of the day observations the change of the dimensionless geodynamo parameters is considered. The evolutionary model includes cooling of the liquid adiabatic core, growing solid core, and the region in the outer part of the core with a subadiabatic temperature gradient. The model covers time period 4.5Ga in the past till 1.5Gy to the future, and produce evolution of the energy sources of the thermal and compositional convection, spatial scales of the convective zone. These quantities are used for Ekman, Rayleigh and Rossby numbers estimates. So far these numbers determine regime of the geomagnetic field generation, we discuss evolution of the geomagnetic field over Earth's evolution.