Answers are grounded in this paper and cite their sources.
Initial results from the University of Minnesota search coil magnetometers aboard the Explorer 45 Satellite (S3-A) show several types of ELF signals during the magnetic storms of December 16–19,1971. The orbit of the satellite at this time was nearly equatorial, with an apogee near 5 RE at 2100 local time, and a perigee below 300 km. The emissions vary during different phases of the storms and also with the position of the spacecraft in the magnetosphere. The location of the plasmapause appears to be a particularly important factor in determining the type and intensity of the signals.
No takes yet. Share an insight, caveat, or question.
Parady et al. (1973) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: