Joe 4 was an American nickname for the first Soviet test of a hydrogen bomb and was on August 12, 1953. It was not a "true" fusion bomb—it was similar to a "boosted" fission bomb, not a multi-stage, megaton-range hydrogen bomb. It utilized a scheme in which fission and fusion fuel was "layered", similar to a design developed by the USA known as the "Alarm Clock." This scheme was know as the "Sloika " model in the Soviet Union, referring to a type of layer cake.

Its power was roughly equivalent to 400 kilotons of TNT. The Soviet physicist Yuli Khariton estimated that Joe 4's yield was 15 — 20% fusion, the rest fission. Being a single-stage weapon, though, it was not capable of being scaled up indefinitely like "true" hydrogen bombs.

The first Soviet test of a "true" hydrogen bomb was on November 22, 1955, and was dubbed RDS-37 by the Soviets. All were at Semipalatinsk Test Site, Kazakhstan.

See also:

Joe One

RDS-37

Soviet atomic bomb project

Ivy Mike

Castle Bravo

External links

• Soviet and Nuclear Weapons History

References

• David Holloway, Stalin and the Bomb: The Soviet Union and Atomic Energy 1939-1956 (Yale University Press, 1995), ISBN 0300066643
• Alexei Kojevnikov, Stalin's Great Science: The Times and Adventures of Soviet Physicists (Imperial College Press, 2004), ISBN 1860944205
• Richard Rhodes, Dark Sun: The Making of the Hydrogen Bomb (Simon and Schuster, 1995), ISBN 068480400X