Radiation field characteristics of lightning discharges in the band 1 kc/s to 100 kc/s

Abstract

The groundwave portion of atmospheric waveforms was examined to determine various characteristics of the radiation field from lightning discharges. Sixty-nine representative waveforms were selected from 1,029 atmospherics from 21 thunderstorms in the Oklahoma and North Texas area. The average amplitude and phase spectra, from 1 kc/s to 100 kc/s, are presented for several groups of atmospherics having distinguishable characteristics. Various relationships involving the total radiated energy, peak field strength, first half cycle length, spectral amplitude peak and frequency of spectra peak are presented. \par The ``normal'' type of atmospheric, composing 86% of the total, is predominately of positive initial polarity, has a spectrum peak near 5 kc/s and has well defined relationships between the parameters mentioned above. All ``other'' types of atmospherics are predominately of negative initial polarity, have a spectrum peak from less than 1 kc/s to 18 kc/s and have no well defined relationships between the various parameters.