Hydrogen bomb

Hydrogen bomb, or thermonuclear bomb, very powerful bomb whose explosive energy is produced by nuclear fusion of hydrogen isotopes, as of 2 deuterium atoms or of a deuterium and a tritium atom. The extremely high temperatures required to start the fusion reaction are produced by an atomic bomb. Lithium-6 deuteride (⁶LiD) is the explosive; neutrons produced by deuterium fusion react with the ⁶Li to produce tritium. The end products are the isotopes of helium, ³He and ⁴He. In warfare hydrogen bombs have the advantage of being far more powerful than atomic bombs, their power being measured in megatons (millions of tons) of TNT, capable of destroying a large city. In defensive and peaceful uses they can be modified so that the radioactivity produced is reduced. Hydrogen bombs were first developed in the United States (1949–52) by Edward Teller and others, and have been tested by the USSR, Great Britain, China, and France.

See also: Fallout; Nuclear weapon.