Protons with kinetic energy e > 70 MeV trapped in the Earth's radiation belts

Abstract

Accurate measurements of under cutoff proton fluxes in the energy range 0.07-9.1 GeV have been performed with the Alpha Magnetic Spectrometer (AMS) at altitudes of 370-390 km in the geographic latitude interval ±51.7°. A clear transition from a Stably Trapped population typical of the Inner Van Allen belts, in the region of the South Atlantic Anomaly (SAA), to a Quasi-Trapped population in the regions underneath the Van Allen belts outside the SAA is observed. The flux maps as a function of the canonical adiabatic variables L, α0, and energy E are presented and discussed. Copyright 2004 by the American Geophysical Union.