Figure 1. Schematic view of the satellite-radiation belt geometry for detecting lightning-induced electron precipitation.

Figure 2. Nighttime orbital passes of the S81-1/SEEP satellite for 9 September 1982.

Figure 3. SEEP detector response during a nighttime pass 9 Sept. 1982. Top two panels are photometer data at 391.4 nm and 630 nm; the third panel is the plasma probe response. The bottom panel shows the particle flux intensities for the TE2 (trapped) and LE5 (precipitating) electron sensors.

Figure 4. LEP bursts (labeled A to G) recorded with the S81-1/SEEP satellite on 9 Sept. 1982 are correlated one-to-one with concurrent ground-based VLF whistlers at Palmer Station, Antarctica. Panels A and B show the VLF spectrograms and the scaled whistlers and sferics. The uppermost insets show the Palmer VLF data with an expanded time scale for the 8 LEP events. The solid lines and arrows represent sferics that were directly identified on these (and other) records, while the dashed lines represent estimates of sferic times based on the dispersion properties of all events. The sampling interval for the energetic particle measurements shown in the lower panel is 64 ms.

Figure 5a. Expanded time scale for LEP event A of Figure 4.

Figure 5b. Expanded time scale for LEP event D of Figure 4.

Figure 6. Expanded time scale for LEP events F and G of Figure 4.

Figure 7. Record of 20 October showing LEP events over North America correlated with whistlers observed at Palmer, Antarctica.

Figure 8. Series of four closely spaced LEP bursts on 6 June 1982.

Figure 9. Extended time record of whistlers and LEP events on 20 October 1982.

Figure 10. Locations where the SEEP satellite identified strong LEP events during its 6 month lifetime.

Figure 11. Histogram of the latitude variation of nighttime LEP events.

Figure 12. Strong lightning activity observed with the SEEP photometer as the satellite passed over a thunderstorm center. Each impluse represents a lightning flash.

Figure 13. Global distribution of lightning activity observed with the SEEP photometer for June to October 1982.

Figure 14. Color Spectrogram of the differential electron energy spectra for LEP events on 9 September 1982.

Figure 15a. Dynamic energy spectra and integral counts for event D of Figure 4.

Figure 15b. Dynamic energy spectra and integral counts for event G of Figure 4.

Figure 16. Comparison of Monte Carlo simulation of LEP event D for 9 September 1982 with observed electron pulse sequence. Simulation results are displaced downward for easier comparison.

Figure 17. Geometry of detector aperture and magnetic field orientation for calculating sensor response in non-isotropic flux.

Figure 18. Best fit obtained for directional electron flux of > 45 keV electrons scattered by whistler. At this altitude (200 km), electrons with pitch angles < 78 degrees will enter the atmosphere at 100 km.

Figure 19. Time delay between sferic and the arrival of the maximum of precipitating electron burst. Time delays at different days will differ since plasmaspheric electron concentrations are not the same.