Extensive Air Showers and Radio Frequency Electromagnetic Fields

Abstract

An estimate is made of the electric field expected from the ionization electrons produced by an extensive air shower moving in the geoelectric field for frequencies from 10 kHz to 10 MHz. The calculations are for a geoelectric production mechanism, and they invoke quite reasonable assumptions regarding the shower development. The calculated fields are found to be comparable with those produced by the geomagnetic mechanism, and fall short of the high values observed in this frequency range. Higher fields cannot be obtained from the present shower mechanism under normal weather conditions, but would require exceptionally large values for the geoelectric field (1 MVm-1) or a model for electron diffusion that is radically different from that assumed here.