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Abstract

Convection in the liquid outer core generates the Earth’s magnetic field. Observations suggest that the secular variation of the magnetic field is weaker under the Pacific region. In turn, this indicates that flow in this region at the surface of the core is weaker. One hypothesis to explain this is that the conductance of lower mantle is higher in this region or, alternatively, that it features stratified core fluid trapped under topographic undulations. This leads to a larger electromagnetic coupling, attenuating the flow. In this work, we will test this hypothesis using numerical simulations of the geodynamo, in which we impose heterogeneous mantle conductance.