Van Allen belt

WordReference Random House Unabridged Dictionary of American English © 2025

Van Al′len belt′, [Physics.]

1. Physics either of two regions of high-energy-charged particles surrounding the earth, the inner region centered at an altitude of 2000 mi. (3200 km) and the outer region at an altitude between 9000 and 12,000 mi. (14,500 and 19,000 km). Also called Van Al′len radia′tion belt′. 

• named after J. A. Van Allen 1955–60

Collins Concise English Dictionary © HarperCollins Publishers::

Van Allen belt noun

1. either of two regions of charged particles above the earth, the inner one extending from 2400 to 5600 kilometres above the earth and the outer one from 13 000 to 19 000 kilometres. The charged particles result from cosmic rays and are trapped by the earth's magnetic field

Etymology: 20th Century: named after its discoverer, J. A. Van Allen