Magnetosphere

The Earth’s magnetic dipole field that extends over a distance from Earth up to approximately 75,000 km around the geomagnetic equator. Charged particles in a specific energy range are trapped in the magnetic field. They move in spirals along the geomagnetic field lines, are reflected back between the magnetic poles acting as mirrors, and form radiation belts where the density of electrons and protons is much higher than outside of these areas. The belts were discovered by van Allen and named ‘van Allen belts’. (ICRP Publication 123, 2013)

ICRP Glossary entry - May 2019

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