Shock Wave Propagation from a Nuclear Blast

Abstract

SINCE the American nuclear explosion on July 9, 1962, at Johnston Island, independent reports from different parts of the world^1–5 have become available relating to the time of onset of some of its magnetic and earth-current effects. Apparently, in some places, the first impetus of the signal, almost instantaneously with the detonation, has not been noticed for some reason or other. The more intense impulse registered after 2 sec after zero time has been, perhaps, thought to be the first. At some other places, no mention is made of anything other than that received almost simultaneously with the blast. This note is to point out a substantial possibility of a hydromagnetic shock propagation due to the blast giving rise to almost simultaneous signal at different parts of the globe. Both the impulses, one at zero time, and the other 2 sec later, are treated from this point of view. It is, incidentally, pointed out that some of the auroral luminosity reported on this occasion might be attributed to the interaction of shock waves with the magnetosphere.