Behavior of geomagnetically trapped electrons injected by high-altitude nuclear detonations

This report describes recent investigations of the data obtained by the Jason sounding rockets during the Argus nuclear weapon tests. These instrumented rockets contained radiation detectors and observed electrons that were injected into the geomagnetic field by the decaying fission fragments from the second Argus explosion. An earlier analysis of the data has been published. The further investigations reported here yielded (1) the orientations of the detectors with respect to a plane perpendicular to local magnetic lines of force, (2) the calibration of the detectors in a planar flux of electrons as functions of electron energy and orientation of the detectors with respect to the electron plane, and (3) a re-evaluation of the Jason data based on items (1) and (2) and on recent data on characteristics of the natural radiation. The conclusions verified the results of the initial analysis regarding the location, width, and stability of the electron ‘shell’ produced by the Argus 2 detonation, as well as the presence of a less intense electron flux in wide regions (wings) away from the shell. In contradiction to the earlier analysis, it was found here that the electron spectrum was much more in agreement with the fission β spectrum. Within the accuracy of the data, the observed spectrum was found to be independent of the spatial locations of the rockets or of the passage of time. During the first 89 hours after the detonation, the decay of the flux appears to follow a time dependence of t−1.15±0.03.