A spatial model of theF-region ionospheric traveling disturbance following a low-altitude nuclear explosion

Abstract

The ƒoF2 fluctuations observed by means of vertical-incidence ionosondes at various Pacific Island stations following the low-altitude, megaton-range nuclear explosion on October 30, 1962, were analyzed. By accounting for the influence of the earth's magnetic field on the response of the ionosphere to the passage of the neutral atmospheric gravity wave (AGW) disturbance, the properties of the neutral AGW disturbance were determined as a function of time after the explosion and distance from the explosion. It was found that the average period of the neutral AGW increases linearly with range, with an additive constant; this constant is related to the initial period of a virtual source located within the ionosphere above the point of the explosion (G0). The amplitude of the neutral AGW varies as exp(−kr), where r is the range from the explosion. Isoionic contours of the ΔN/N fluctuations were computed. Four cases of the expanding ionospheric disturbance are given, for 22, 44, 65, and 109 minutes after the explosion; these times correspond to the expansion of the leading edge of the neutral AGW to 1000, 2000, 3000, and 50000 km from the explosion. The Housatonic data agree well with the published theoretical papers on AGW's generated by impulsive, low-altitude sources.