  Based on the generic acceleration model, which suggests different types of
electromagnetic interactions between the cosmic charged particles and the
different configurations of the electromagnetic (plasma) fields, the ultra high
energy cosmic rays are studied. The plasma fields are assumed to vary,
spatially and temporally. The well-known Fermi accelerations are excluded.
Seeking for simplicity, it is assumed that the energy loss due to different
physical processes is negligibly small. The energy available to the plasma
sector is calculated in four types of electromagnetic fields. It has been found
that the drift in a time--varying magnetic field is extremely energetic. The
energy scale widely exceeds the Greisen-Zatsepin-Kuzmin (GZK) cutoff. The
polarization drift in a time--varying electric field is also able to raise the
energy of cosmic rays to an extreme value. It can be compared with the Hillas
mechanism. The drift in a spatially--varying magnetic field is almost as strong
as the polarization drift. The curvature drift in a non--uniform magnetic field
and a vanishing electric field is very weak.
