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A Look Back At Bombing the Van Allen Belts
An anonymous reader points out a recent story at NPR describing one of the greatest lightshows in history — a US hydrogen bomb test 250 miles above the Pacific Ocean in 1962. The mission came about after James Van Allen confirmed the existence of radiation belts around the earth that now bear his name. As it turns out, the same day Van Allen announced his findings at a press conference, he "agreed with the military to get involved with a project to set off atomic bombs in the magnetosphere to see if they could disrupt it." According to NPR, "The plan was to send rockets hundreds of miles up, higher than the Earth's atmosphere, and then detonate nuclear weapons to see: a) If a bomb's radiation would make it harder to see what was up there (like incoming Russian missiles!); b) If an explosion would do any damage to objects nearby; c) If the Van Allen belts would move a blast down the bands to an earthly target (Moscow! for example); and — most peculiar — d) if a man-made explosion might 'alter' the natural shape of the belts." The article is accompanied by a podcast and a video with recently declassified views of the test. They also explain how the different colors of light in the sky were produced.
Isaac Azimov wrote a short sci-fi story about an explorer, who had just come back from visiting the newly contacted planet "Earth", adding humans to the "Register Of Intelligent Life". Some minutes later, after the explorer explained how humans tested atomic bombs "on their own planet" the registrar erased the entry as being unqualified for inclusion under "Intelligent".
Those radiation belts are composed of trapped electron and proton particles, bouncing back and forth along those magnetic field lines. There are several numerical models that predict what the population of these particles based on their location, and general behavior under different conditions (solar cycle variations, solar flares, etc).
Anyone building a satellite will use those models to determine what levels of radiation levels the satellite will encounter along its orbit, and add on the appropriate level of shielding to protect the electronics.
A nuclear bomb will never be able to alter the shape of the belts. All it will do is add a spectacular amount of electron and proton particles to the radiation belt, potentially frying the electronics of most of the low to medium orbit satellite (geosynchronous ones will probably be ok). Depending on the size of the bomb, the radiation belt may take weeks or even months to return to a 'natural' state.
There are some experiments in the works to 'tweak' the radiation belts by beaming low frequency EM waves, to change the energy of the existing particle populations. In theory, that will enable some of the particles to become 'untrapped', thereby reducing the overall population.