Propagation of ground wave electromagnetic signal, with particular reference to a pulse of nuclear origin

Abstract

The physical phenomena of the theory of propagation of an electromagnetic pulse at low radiofrequencies are scrutinized from the viewpoint of detection systems. Methods for tagging a point in time on the pulse are described theoretically. The iilter action of the propagation medium together with various select receiver iilters are considered in the analysis. A particular electromagnetic pulse observed and recorded at a short distance from the source (44.6 km) is propagated theoretically to a great distance (>2OOO km) as a ground wave. The behavior of the tagged point in time on the pulse is studied both as a function of distance and as a function of the conductivity of the ground. The computer method is also used to determine the attenuation vs. distance function of the pulse. This study provides information of general interest on the subject of low radiofrequency pulse propagation. In addition, the results of this study form a basis for the determination of the effects of ground conductivity on location 5 ding systems, based on the theory of propagation of an electromagnetic pulse. in this paper was sponsored by the U. S. Air Force Electronic Systems Manuscript receix-ed September 29, 1965. The research reported Div., Air Force Systems Command, under contract AF19(628)2390, available as ED-TR-65-381. Further reproduction is authorized to satisfy the needs of the U. S. Government. J. R. Johler is with the Ionospheric Telecommunications Lab.,