Geomagnetism
Geomagnetism is the branch of geophysics that investigates Earth’s magnetic field, its origins in the planet’s core, its spatial structure, and its variations over timescales from seconds to millions of years. The discipline spans internal field generation by the geodynamo, crustal magnetization, and external sources in the ionosphere and magnetosphere, with applications in navigation, resource exploration, and space-weather hazard mitigation.
