Precipitation of low energy electrons near the lower edge of inner radiation belt

Abstract

Considering Landau resonance interaction between energetic electrons and plasmaspheric hiss of natural origin, precipitation of low energy (eV and keV) electrons near the lower edge of the inner radiation belt is studied. The results show that the off-equatorial Landau resonance acts on resonant electrons of energy as low as ~45 eV, whereas the first order cyclotron resonance acts on electrons of higher energy (>10⁴ keV). The maximum flux of precipitating electrons in this region by Landau resonance is found to be ~10^-3 times the trapped flux, which is consistent with the observed spectrum of precipitated energetic electrons in the South Atlantic Magnetic Anomaly (SAMA) region. Thus, the off-equatorial Landau resonance satisfactorily explain the loss of low energy electrons near the lower edge of inner radiation belt, the upper limit of energy of resonant electrons precipitated by this mechanism being ~210 keV.