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

The groundwave portion of atmospheric wavefor ms was examin ed to determine vario us characterist ics of the radiation field from li ghtn in g discha rges. Sixty-n ine representative waveforms were' selected from 1,029 atmospherics from 21 thunderstor ms in the Oklahoma and No rt h Texas area. The average ampli t ude and pha e spectra, from 1 kc/s to 100 kc/s, are presented for several groups of atmospherics hav ing distin guishable cha racteristics. Various relationships involving the total rad iated energy, peak fi eld strength, first half cycle length, spectral ampli tude peak and frequency of spectra peak are presented. The " normal" type of atmosplleric, composin g 86 percent of the total, is predominately of positive ini t ia l polarity, has a spectrum peak near 5 kc/s and has well defin ed relationships betwee n t he parameters mentioned above. All "other" types of atmospherics are predomin ately of negative initial polar ity, have a spectrum peak from less than 1 kc/ to 18 kc/s and have no well defined relationships between the various parameters.