  We investigate the motion of the primary beam outside the light cylinder in
the pulsar wind. Inside the light cylinder both primary and secondary plasma
move along dipole magnetic field lines where their energies can be arbitrary.
But at larger distances the theory predicts quasi-radial motion with the
velocity exactly corresponding to the drift velocity which cannot be the same
for primary and secondary plasma. Hence, the deceleration of the primary beam
is to take place simultaneously resulting in the acceleration of the secondary
plasma. We investigate this process in the three-fluid MHD approximation and
demonstrate that for most pulsars the energy of the beam remains practically
unchanged. Only for young radio pulsars (Crab, Vela) essential deceleration up
to the energy of the secondary plasma takes place outside the fast magnetosonic
surface $r_{\rm F} \sim (10$-$100) R_{\rm L}$, the energy of secondary plasma
itself increasing insufficiently.
