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'Joe 4' (Warhead name: RDS-6s (''Reaktivnyi Dvigatel Stalina''; Stalin's Rocket Engine)) was an American nickname for the first Soviet test of a thermonuclear weapon and was on August 12, 1953. It was not a "true" hydrogen bomb—it was similar to a "boosted" fission bomb rather than a multi-stage, megaton-range fusion weapon. It utilized a scheme in which fission and fusion fuel were "layered", a design known as the '''Sloika''' ((Ru: Слойка) named after a type of layer cake) model in the Soviet Union. A similar design was earlier theorized, but never tested, in the USA as the "Alarm Clock".
The Soviet thermonuclear weapons program initially researched two weapon designs. One design was the '''Sloika''' (RDS-6s), the other design was the '''Truba''' (RDS-6t). The RDS-6t was a two stage gun-type bomb with a deuterium-tritium secondary and was similar to the U.S. “classical Super” design. However, when the United States detonated a hydrogen bomb in the Pacific in 1952 (Ivy Mike), higher priority was given to the RDS-6s design, which was considered to be more likely to work. ^[1]
Joe 4 detonated with a force equivalent to 400 kilotons of TNT. The Soviet physicist Yuli Khariton estimated that Joe 4's yield was 15% to 20% fusion, the rest fission boosted by the fast neutrons released in the fusion. Being a single-stage weapon, though, it was not capable of being scaled up indefinitely like "true" hydrogen bombs (see Teller-Ulam design for more details on the distinctions between fusion weapons).
Despite its inability to be scaled into the megaton range, the detonation was used by Soviet diplomats as leverage. The Soviets claimed that they too had a hydrogen bomb, but unlike the United States' first thermonuclear weapon, theirs was deployable (i.e. could be dropped from a bomber). Despite this claim, U.S. experts disputed its standing as a "true" hydrogen bomb. The United States did not develop a deployable version of its hydrogen bomb until 1954. The ''Sloika'' model was never widely deployed.
The first Soviet test of a "true" hydrogen bomb was on November 22, 1955, the RDS-37 warhead. All were at Semipalatinsk Test Site, Kazakhstan.

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See also

External links

References

Notes

See also

★ Joe 1

★ RDS-37

★ Soviet atomic bomb project

★ Ivy Mike

★ Castle Bravo

External links

★ Soviet and Nuclear Weapons History

★ Soviet/Russian Nuclear Arsenal

★ Video footage of the Joe-4 Nuclear Test

References

★ David Holloway, ''Stalin and the Bomb: The Soviet Union and Atomic Energy 1939-1956'' (Yale University Press, 1995), ISBN 0-300-06664-3

★ Alexei Kojevnikov, ''Stalin's Great Science: The Times and Adventures of Soviet Physicists'' (Imperial College Press, 2004), ISBN 1-86094-420-5

★ Richard Rhodes, ''Dark Sun: The Making of the Hydrogen Bomb'' (Simon and Schuster, 1995), ISBN 0-684-80400-X

Notes

1. Atomic Forum; Soviet/Russian Nuclear Arsenal, "[1]"