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Van Allen, James (Alfred)

radiation iowa war belts

(1914– ) US physicist: discovered the magnetosphere (the Van Allen radiation belts).

Van Allen was educated at Iowa Wesleyan College and the University of Iowa. During the Second World War he served in the US Navy, helping to develop the radio proximity fuse for missiles and anti-aircraft shells. Afterwards he worked at Johns Hopkins University, and was appointed professor of physics at the University of Iowa in 1951.

Van Allen’s contributions, to a large extent, reflected his war-time experiences with rocketry and miniaturized electronics. After the war he used left-over German V-2 rockets to carry instruments to measure cosmic radiation into the upper atmosphere, and in 1958 put a Geiger radiation counter on the first American satellite, Explorer 1. This and later Explorer satellites revealed a region of high levels of radiation at a height of several hundred kilometres above the Earth. More detailed investigation has since shown that there are in fact two toroidal (doughnut-shaped) belts, which are created by charged particles (electrons and protons) from the Sun being trapped by the Earth’s magnetic field. These Van Allen radiation belts constitute the Earth’s magnetosphere.

Van Andel, Jay - Overview, Personal Life, Career Details, Social and Economic Impact, Chronology: Jay Van Andel [next] [back] Van Allen, James

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