Belts that are sources of intense radiation surrounding the earth, consisting of high-energy charged particles trapped in the earth's magnetic field within which they follow roughly helical paths. They were discovered in 1958 by James Van Allen (1914– ) as a result of radiation detectors carried by Explorer satellites. The lower belt, extending from 1000 to 5000 km above the equator, contains electrons and protons, while the upper belt, 15000–25000 km above the equator, contains mainly electrons (see illustration).
Van Allen belts
- linear energy transfer
- linear equation
- linear expansivity
- linear momentum
- linear motor
- lines of force
- Linz-Donawitz process
- liquation
- liquefaction of gases
- liquefied petroleum gas
- liquid
- liquid crystal
- liquid-crystal display
- liquid-drop model
- Lissajous figures
- litre
- Lloyd's mirror
- loaded concrete
- Local Group
- local oscillator
- localization
- locus
- Lodge, Sir Oliver Joseph
- logarithm
- logarithmic scale