Modeling energetic electron precipitation near the South Atlantic anomaly

Amplitude enhancement of events in the South Atlantic anomaly region

“…This is in agreement with the finding from ionosonde results by Abdu and Batista (1977) that particle precipitation is a regular source of ionization in the E-region over SAMA even under quiet conditions. Abel and Thorne (1999) also have shown from numerical simulation study that precipitating electrons should be a prominent ionization source near the SAMA but relatively insignificant elsewhere. We may attribute SCðHÞ enhancements at the center of the SAMA to the ionization, notably, in the E-region over the SAMA due to a downward flux of charged particles (electrons) at the center of SAMA.…”

Geomagnetic phenomena in the South Atlantic anomaly region in Brazil

“…We ascribe the enhancement of H amplitudes at SMS to the electron precipitation taking place in the SAMA region. Abel and Thorne (1999) have shown that precipitating electrons should be a prominent mesospheric ionization source near the SAMA but relatively insignificant elsewhere. The phenomenon of charged particle precipitation in the SAMA region is attributed to pitch angle scattering by collisions or wave particle interaction (Macdonald and Walt, 1962;Roederer, 1970;Pinto and Gonzalez, 1989b;Jayanthi et al, 1997a,b).…”

Unusual ionospheric absorption characterizing energetic electron precipitation into the South Atlantic Magnetic Anomaly

“…Obara et al (2000) displayed an evident increase of 30-1100 keV energy electrons in the inner radiation belt of L < 1.5 near the maximum depression (D st ∼ − 200 nT) during the strong geomagnetic storm from the NOAA-12 satellite. Thus it is expected that energetic electrons in the inner radiation belt could precipitate into the SAMA ionosphere during the strong geomagnetic storm, taking account of a numerical simulation of electron pitch angle scattering in an asymmetric magnetic field environment (Abel and Thorne, 1999 We summarize characteristics of the present unusual absorption observed during the strong geomagnetic storm on September 22-23, 1999, as follows.…”