  For the first time accurate measurements of electron and positron fluxes in
the energy range 0.2-10 GeV have been performed with the Alpha Magnetic
Spectometer (AMS) instrument at altitudes of 370-390 Km in the geographic
latitude interval +/- 51.7 deg. We present an original analysis of the AMS
data, focused on the study of the under-cutoff component of these fluxes,
outside the region of the South Atlantic Anomaly (SAA). A separation in
quasi-trapped, long lifetime (O(10 s)), and albedo, short life time (O(100
ms)), components is found. The flux maps as a function of the canonical
adiabatic variables L, alpha0 are determined in the interval
(L,alpha0)=(0.95-3,0-90) for electrons with E less than 10 GeV, and positrons
with E less than 3 GeV. The results are compared with existing data at lower
energies and in similar L, alpha0 range. The properties of the observed
under-cutoff particles are also investigated in terms of their residence times
and geographical origin. The resulting distributions are discussed and related
to the characteristics of the drift shells observed by AMS.
