An equivalent current system method and its application to Earth's core field

An inversion framework was applied for both the entire and the non-dipole core field part of the geomagnetic field model CHAOS-6 using data from three different satellite missions and ground observatories. This framework uses a forward model of equivalent stationary current systems, partially based on geodynamo simulations of low viscosity, to invert for. To validate the method, a systematic series of synthetic tests were carried out focusing on the difference of performance between models assuming radially aligned source axes (quasi-toroidal configuration) and models having no restrictions on the sources' spatial attitude. Authors also present here estimations using geomagnetic model data with special attention to the geographical distribution of the resulting current systems and its comparison with the properties of core surface flows inverted by them and other research groups. The full spatial structure of the inverted current densities is revealed as well.