Analysis of Satellite Data on Precipitating Particles in Coordination with ELF Propagation Anomalies

The report describes the analyses of satellite energetic particle data for coordination with ELF transmission anomalies. The precipitating electrons typically exhibit pronounced flux and spectral variations on a small latitude scale. The electron fluxes and energy spectra, when averaged over a wide latitude interval, are presented as well as the resulting ion-pair production rates and the free electron concentrations in the lower ionosphere. Significant enhancements over the quiet-time night profiles were often observed. The particle measurements indicated significant enhancements in the D-region electron densities during all of the times of the ELF transmission anomalies. Based on the electron and ion concentrations a waveguide model computer program, which was developed at the Naval Electronics Laboratory Center, was used to calculate the mode constants applicable in the extremely low frequency range. The program predicts the measured field strengths in an undisturbed uniformly stratified ionosphere, but for the nights of enhanced ionization the calculated field strengths indicate increases in contrast to the observed decreases.