Does ELF Chorus Show Evidence of Power Line Stimulation?

Abstract

It has previously been reported (Luette et al, 1977) that electromagnetic chorus exhibits a longitudinal dependence, with enhanced occurrence over population centers (Alaska-New Zealand, Eastern U.S.—Canada, Western Europe and Western Siberia). This result has been cited as possible evidence of Power Line Harmonic Radiation (PLR) control of magnetospheric chorus. In this paper we report an analogous study using chorus data from OGO-5 to test this result. Chorus is found to exhibit maxima over the Eastern USSR, Greenland and Central Siberia and minima over central and Eastern Canada, a distribution significantly different than the OGO-3 result. This gross discrepancy is explained as an effect of data oversampling (persistence) in the method of analysis used in the previous study. The OGO-5 data are reanalyzed with the oversampling removed. It is found that none of the longitudinal maxima or minima are then statistically significant (<2σ). Thus, we find no statistically significant correlation between longitude and chorus occurrence which implies that there is little or no evidence of PLR effects on chorus triggering.