Convenors: Gary Egbert (USA), Astrid Maute (USA), Patrick Alken (USA), Nils Olsen (Denmark)

Recent developments in EM induction modeling and inversion, together with new global geomagnetic datasets (e.g., from the SWARM mission), present exciting new opportunities for imaging three-dimensional electrical conductivity variations in the mantle. Results from these studies may ultimately provide important new constraints on the composition (e.g., water content), physical state, and geodynamics of the deep Earth. Probably the greatest obstacle to success in this endeavor is the need to accurately characterize the spatially complex external source fields, which must be disentangled from the induced internal fields to image mantle conductivity reliably. Observations of the time-varying magnetic fields remain sparse, making a direct empirical separation very challenging. One promising approach is to make use of physics-based numerical models of ionospheric and magnetospheric current systems. These are becoming increasingly sophisticated, and may provide additional constraints on source geometries, and enable significant advances in realistic modeling of external sources. This symposium seeks to bring the induction and external source communities together, to explore progress on combining ground- and satellite-based geomagnetic observations with numerical models for improved separation, characterization and modeling of external source current systems in the ionosphere and magnetosphere.

Contributions on improving source models for mantle induction studies are sought, along with novel uses of satellite and ground based data to validate or improve models for external source studies. We also welcome contributions on other aspects of global-scale studies of mantle electrical conductivity, including theoretical or methodological developments, and results based on analysis of data from ongoing or past satellite magnetic missions, as well as ground based arrays.