Thermonuclear bombs operate on energy released from a fusion reaction where hydrogen isotopes, usually an interaction of deuterium and tritium, combine to produce helium atoms. Because the light materials must overcome the repellent forces of their protons this can only occur at extremely high temperatures (millions of degrees). A thermonuclear explosion occurs in several stages. The first stages are an implosion-type of fission bomb. However, the fission bomb is exploded inside of a uranium reflector that directs the force of the fission explosion back onto the fusion materials thereby directing enough heat and energy onto them to initiate a fusion reaction. The fusion explosion then affects the uranium reflector causing it to fission also. This adds to the explosion and also creates materials that form fallout. Thermonuclear bombs can be many times more powerful than fission-type bombs and their equivalent energy is usually expressed in megatons of TNT. The USA exploded the first thermonuclear bomb on 01 November 1952 on Enewetak atoll in the Pacific.
Atomic cloud during Baker Day blast at Bikini Atoll, 25 July 1946.
Operation Crossroads: Atomic cloud during Baker Day blast at Bikini Atoll in the Pacific. Here, the atomic cloud lofts over the target fleet. Sweeping out in all directions is a haze of water, steam, spray and radioactive substances obscuring the sky over all but the outer fringes of the target fleet a few minutes after the blast of 25 July 1946.
Many of the ships that were at this test had to be scuttled because of radioactive contamination. Bikini Atoll is still being cleaned up today at great expense.
Ironically, the bikini swimsuit was introduced at a Paris fashion show just 3 days later.
Photo: US Department of Defense.
Department of the Navy - Naval Photographic Center.
National Archives and Records Administration.
Still Picture Branch; College Park, Maryland.