Theoretical analysis of precipitating energetic electrons in the South Atlantic Anomaly

A detailed analysis of old and new theories and experimental data is presented to assess the importance of energetic electron (20 to 300 KeV) precipitation in the South Atlantic Anomaly (SAA) for the electon density balance of the ionospheric E and D regions. The 'geometrical' theory of precipitation (Torr et al., 1974) is compared with earlier theories, and all are shown to be appropriate for obtaining an average value of the precipitation flux, but completely inaccurate for evaluating ionospheric effects in the middle latitudes, and especially in the SAA. An alternative model, which accounts for multiple electron scattering, is derived, and it is shown that this model provides better agreement with experimental data than any of the previous ones.