  The evolution of plasma entropy and the process of plasma energy
re-distribution at the collisionless plasma shock front are evaluated based on
the high temporal resolution data from the four MMS spacecraft during the
crossing of the terrestrial bow shock. The ion distribution function has been
separated into the populations with different characteristic behavior in the
vicinity of the shock: the upstream core population, the reflected ions; the
gyrating ions; the ions trapped in the vicinity of the shock, and the
downstream core population. The values of ion and electron moments (density,
bulk velocity, and temperature) have been determined separately for these
populations. It was shown that the solar wind core population bulk velocity
slows down mainly in the ramp with the electrostatic potential increase but not
in the foot region as it was supposed. The reflected ion population determine
the foot region properties, so that the proton temperature peak in the foot
region is the effect of the relative motion of the different ion populations,
rather than an actual increase in the thermal speed of any of the ion
population. The ion entropy evaluated showed a significant increase across the
shock the enhancement of the ion entropy occurs in the foot of the shock front
and at the ramp, where the reflected ions are emerging in addition to the
upstream solar wind ions, the anisotropy growing to generate the bursts of
ion-scales electrostatic waves. The entropy of electrons across the shock
doesn't show significant change - electron heating goes almost adiabatically.
