Van Allen radiation belts

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Two zones of charged particles around the Earth's magnetosphere, discovered in 1958 by US physicist James Van Allen. The atomic particles come from the Earth's upper atmosphere and the solar wind, and are trapped by the Earth's magnetic field. The inner belt lies 1,000–5,000 km/600–3,000 mi above the Equator, and contains protons and electrons. The outer belt lies 15,000–25,000 km/9,000–15,000 mi above the Equator, but is lower around the magnetic poles. It contains mostly electrons from the solar wind.

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