 The EMP mechanism that had been hypothesized before "Operation Fishbowl" had been conclusively disproven by the "Starfish Prime" test.Prompt gamma ray output measurements on these later tests were also carefully obtained so that a new theory of the mechanism for high-altitude EMP could be developed and confirmed.That new theory about the generation of nuclear EMP was developed by Los Alamos physicist Conrad Longmire in 1963, and it is the high-altitude nuclear EMP theory that is still used today.