The high-energy, charged particles that are trapped into orbits by the geomagnetic field, forming radiation belts that surround the Earth. The belts consist primarily of electrons and protons and extend from a few hundred kilometers above the Earth to a distance of about 8 R_e (R_e = radius of Earth = 6371 km = 3959 mi). James Van Allen and coworkers discovered them in 1958 using radiation detectors carried on satellites Explorer 1 and 3, and they are often referred to as the Van Allen belts.