Publication Date:
2023-08-02
Description:
The core surface flow and its radial derivative are related to geomagnetic field and its first time derivative (Secular Variation, SV) through the three components of the induction equation. Because the total geomagnetic field in the insulating mantle can be reconstructed from its radial component alone, most studies, until now, have considered only the radial component of the induction equation. Then, core surface flows can be inverted from this non-linear relationship between the flow and the SV. Here, we show that the horizontal components of the diffusion-less induction equation provide a relationship between the flow and the shear. To obtain this relationship we need to consider both the poloidal and the toroidal part of the induction equation. The use of dynamo simulations, where the velocity obeys a stress-free boundary condition, allowed us to test our derivation of the shear. We successfully recover the shear from the synthetic data. Finally, we used a geomagnetic field model based on satellite data to calculate the radial shear of the flow at the top of the core.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
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