Effect of nuclear detonation on the geomagnetic field at Palo Alto, California

Abstract

On July 9, 1962, shortly after 0900 UT, the United States detonated a nuclear device in the megaton range at an altitude of over 200 miles near Johnston Island in the Pacific Ocean. The rocketborne device was designed, among other reasons, to test the effects of such a detonation on electromagnetic phenomena in the high atmosphere and the resultant disruption of communication bands. As expected, the shot caused a very large perturbation on the normal magnetic field of the earth for at least six minutes immediately after the detonation. This change was recorded by two model X‐4936 rubidium vapor magnetometers in Palo Alto, California. One was located at site 501, Stanford University, and the other at Varian Associates, less than a mile away. The chart speed at the Stanford site was 6 inches per hour with a selected full‐scale sensitivity of 20 γ; the Varian system recorded at 2 inches per minute and 2 γ full scale. Unfortunately, the magnitude and frequency of the initial oscillations were much larger than expected and, though the magnetometer sensing head is capable of following millisecond field variations, the recorder response time was such that the precise amplitude and frequency of the initial oscillations were not accurately measured. By detailed comparison and analysis of both records, however, the character and general magnitude of these oscillations were determined and are reproduced in Figure 1.

Anthropogenic Space Weather

“…The geomagnetic disturbance caused by Starfish was reported to have been observed worldwide: in the Pacific and the continental United States (Bomke et al, 1964;Breiner, 1963;Miles and Lepping, 1964;Unterberger and Byerly, 1962), in Canada (Baker and Strome, 1962), in Tasmania, Australia (Edwards and Reid, 1964), in Peru (Casaverde et al, 1963), in India (Pisharoty, 1962), in France and in the Kerguelen Islands, South Indian Ocean (both these by Roquet et al, 1963). A noted characteristic was the near-instantaneous arrival of the prompt onset, implying the propagation of the initial disturbance by electromagnetic means, at or near the speed of light.…”

Anthropogenic Space Weather

“…The geomagnetic disturbance caused by Starfish was reported to have been observed worldwide: in the Pacific and the continental United States (Bomke et al, 1964;Breiner, 1963;Miles and Lepping, 1964;Unterberger and Byerly, 1962), in Canada (Baker and Strome, 1962), in Tasmania, Australia (Edwards andReid, 1964), in Peru (Casaverde et al, 1963), in India (Pisharoty, 1962), in France and in the Kerguelen Islands, South Indian Ocean (both these by Roquet et al, 1963). A noted characteristic was the near-instantaneous arrival of the prompt onset, implying the propagation of the initial disturbance by electromagnetic means, at or near the speed of light.…”

A comparison of high-altitude nuclear explosion effects in theElayer with variations in geomagnetic field strength

“…Bay disturbances of the type normally associated with magnetic storms, although on a much smaller scale, have been reported from sites as remote from the detonation as India [Pisharoty, 1962] and the Union of South Africa [van Wijk, 1962]. Complex micropulsation-like perturbations in the geomagnetic field have been reported as well, notably from stations located throughout the western hemisphere [Baker and Strome, 1962;Unterberger and Byefly, 1962;Ashburn et al, 1962;Breiner, 1963;Crook et al, 1963;Casaverde et al, 1963;Wilson and Sugiura, 1963;Burch and Green, 1962]. The explosion-associated magnetic field variations reported by North and South American observers have exhibited strikingly similar behavior; that is, the alternate increases and decreases in geomagnetic field strength measured at each of these locations immediately after the explosion have followed a similar pattern.…”