Inverse problem for the Earth's core evolution model

The size and the age of the inner core impose constraints in modeling of the Earth's core evolution. The origin of the solid core corresponds to the change in convection regime in the core and, correspondingly, to the change in the magnetic field behavior. Meanwhile the standard evolutionary models predict quite young inner core that is not supported by the palaeomagnetic observations, which claim existence of geomagnetic field older than 3 Gy. We solve the inverse problem and find parameters of the model with the inner core older than 3 Gy.