Energetic charged particle and electromagnetic wave injections into space

Abstract

Man’s first, and most dramatic, activities in this field were to conduct high altitude (400...500 kin) nuclear explosions in the late 1950s and early 1960s. The Argus experiment created charged particles which affected the Van Allen trapped radiation belts. The Starfish experiment of 9 July 1962 had. a higher yield (l.L~Megaton (Mt)) than the Argus explosions (~1 kt); an intense artificial radiation belt was created, and this lasted longer (many years) since the source was at a lower latitude (Johnson Island, Pacific Ocean) than that used for the earlier Argus shots (South Atlantic). Three Soviet explosions in October and November 1962 made artificial radiation belts which were less intense than that due to Starfi~h. Because their source was at a higher latitude (Siberia) these belts decayed rather rapidly. Interesting effects have been observed in the VLF and ELF radio bands after high—altitude nuclear explosions. At the instant of detonation of Starfish, electromagnetic signals were radiated; a whistler was received in the opposite hemisphere. Only seconds after the explosion, artificial aurorae were observed in New Zealand and the absorption of cosmic radio noise by the Alaskan ionosphere was increased. The peak absorption occurred within one minute, with recovery to normal conditions taking a few hours. After a few minutes the ionosonde in Jamaica indicated greater absorption in the lower ionosphere. Also some minutes after the explosion the Q value of the resonant (8 Hz) earth-ionosphere cavity decreased; after about three hours it returned to its normal value. The change may be explained, not only by the enhancement of ionisation below the explosion, but also by the world—wide (low-latitude) ionisation produced by the trapped energetic electrons, arising from neutron decay, drifting eastwards in longitude. Synchrotron radiation from the ~ 2 million electron volt (MeV) electrons produced by the explosion was detected by radioastronomy observatories at low latitudes.