F2-region electron concentration enhancements from inner radiation belt particles

Existence of electron concentration enhancements over the South Pacific and Africa at small L values is established from satellite data. In the fall of 1963, at a local time of 0130, and at an altitude of 300 km, the concentration at the center of the South Pacific enhancement was approximately 3 × 105 cm−3 greater than the base level. The enhancement is relatively stable and does not appear to be restricted in local time. The power input required to maintain the enhancement is estimated at 1017 ergs/sec, a value that is a few tenths the input in the auroral zones. Inner radiation belt electrons with energy in the range from a few tens ev to a few kev are the suggested source of ionization. A second region of enhanced electron concentration, which is stronger but apparently less geographically stable than that in the South Pacific, extends from near the South Atlantic magnetic anomaly eastward to the eastern edge of Africa and is approximately symmetric about the magnetic equator.