"Geomagnetism" is the study of Geomagnetism is the study of the dynamics of the Earth's magnetic field, which is produced in the inner core.
A few notable experts of "Geomagnetism" include Emiliani, Cesare, Serway, Raymond A.
Why study "Geomagnetism"? The Earth's magnetic field is predominantly a geo-axial dipole, with north and south magnetic poles located near the geographic poles that undergo periodic reversals and excursions.
Intensity, Inclination, Declination are a few categories of "Geomagnetism".