The main part of the geomagnetic field arises from the Earth’s outer core. It extends to a distance of ~10 Earth radii and acts as to shield against solar and cosmic particle radiation, and determines the strength and geometry of ionospheric and magnetospheric current systems. These systems vary as Earth’s field changes due to core dynamics but are also profoundly altered during space weather events.
Understanding the processes responsible for these various magnetic field contributions and tracking their variability in time is there vital to ensure the preparedness of modern technology on ground and in space on which society increasingly depends. Most of our knowledge of the spatial and temporal variations of the recent geomagnetic field has been achieved through observations from high precision magnetic satellite missions, such as Ørsted, CHAMP, and Swarm. However, a multitude of satellites in Low Earth Orbit (LEO) carry avionics magnetometers for satellite attitude determination and control. These magnetometers, by design, do not meet high precision scientific requirements, but have been shown to add valuable information in characterizing the geomagnetic field and its environment after appropriate calibration.
Edited by Claudia Stolle, Nils Olsen, Brian J. Anderson,Eelco Doornbos,