Application of a new magnetospheric field model to 3-D inversion of Swarm magnetic data in terms of mantle electrical conductivity

The large-scale electrical conductivity structures in the deep Earth's mantle, in the depth range of 670 to 1400 km, can be in principle determined from Swarm-observed induction response to time-variable magnetospheric currents (Velímský & Knopp 2021). However, these efforts have been so far encumbered by limited spatio-temporal description of the magnetospheric field from moving satellite platforms. In particular, the polar electrojets (PEJs) and field-aligned currents (FACs) are sources of a strong bias in the spherical-harmonic analysis of Swarm magnetic data. An electric circuit model of PEJs and FACs (Martinec & Velímský 2022) provides a novel data processing tool to suppress the bias and obtain a reliable model of the large-scale magnetospheric field during magnetically disturbed times. In this contribution we apply the new magnetospheric field model to the 3-D time-domain  forward and inverse modelling of global electromagnetic induction. We determine its impact on the sensitivity and resolution of the inverse problem, and proceed with regularized 1-D and 3-D inversions to update the electrical conductivity model of the deep mantle.