Designs of Nuclear Bombs
To build an atomic bomb, you need:
  • A source of fissionable or fusionable fuel
  • A triggering device
  • A way to allow the majority of fuel to fission or fuse before the explosion occurs (otherwise the bomb will fizzle out)

The first nuclear bombs were fission devices, and the later fusion bombs required a fission-bomb trigger. We will discuss the designs of the following devices:

  • Fission bombs (in general)
  • Gun-triggered fission bomb (Little Boy), which was detonated over Hiroshima, Japan, in 1945
  • Implosion-triggered fission bomb (Fat Man), which was detonated over Nagasaki, Japan, in 1945
  • Fusion bombs (in general)
  • Teller-Ulam design of a hydrogen fusion bomb, which was test-detonated on Elugelap Island in 1952