The quest to build an electromagnetic weapon — an e-bomb, in military jargon — was sparked on 8 July 1962, when the United States carried out Starfish Prime, the largest high-altitude nuclear test that had ever been attempted. The 1.4-megaton thermonuclear warhead, detonated 400 kilometres above the central Pacific Ocean at 9 seconds past 11 p.m., Hawaii time, blasted huge swarms of charged particles outwards along Earth's magnetic field. Their gyrations generated a pulse of microwave energy that drove measuring instruments off the scale. Artificial auroras lit up the night across swathes of ocean. And in Honolulu, more than 1,300 kilometres from the detonation point, the pulse set off burglar alarms, knocked out street lights and tripped power-line circuit breakers. Nothing like Starfish Prime has been seen since August 1963, when the Partial Test Ban Treaty outlawed nuclear explosions anywhere but underground. But the test showcased the potential destructiveness of an electromagnetic pulse to military planners on both sides of the cold-war divide, and launched them into a race to harness it as a weapon using a non-nuclear source.
Language: en
LA - en SN - 0028-0836 UR - http://dx.doi.org/10.1038/489198a ID - ref1 ER -