Origin of the high energy proton component below the geomagnetic cutoff   in near earth orbit
  The high flux proton component observed by AMS below the geomagnetic cutoff can be well accounted for by assuming these particles to be secondaries originating from the interaction of Cosmic Ray protons with the atmosphere. Simulation results are reported 
L. Derome, M. Buenerd, A. Barrau, A. Bouchet, A. Menchaca-Rocha, and   T. Thuillier