Joe-4

The "Joe-4" was the Western designation for the Soviet Union's RDS-6, a deliverable thermonuclear bomb detonated on August 12, 1953. This weapon was a significant milestone, marking the first use of solid lithium-6 deuteride as fusion fuel and achieving a yield of 400 kilotons.1

A thermonuclear bomb, also known as a hydrogen bomb, derives its immense power from nuclear fusion, where hydrogen isotopes combine to form helium under extreme temperatures. These high temperatures are generated by the detonation of an atomic bomb, which acts as the primary stage. Unlike atomic bombs that rely on nuclear fission (splitting heavy nuclei), thermonuclear bombs utilize fusion (combining light nuclei). This process converts a small amount of mass into a tremendous amount of energy, as described by Einstein's famous equation, (E = mc^2). Thermonuclear bombs can be hundreds or thousands of times more powerful than atomic bombs, with yields measured in megatons.2