  Averaged over ensemble of initial conditions kinetic transport equations of
weakly coupled systems of quarks and gluons are derived. These equations
account for the correlators of fluctuations of particles and classical gluon
fields. The isotropization of particle momenta by field fluctuations at the
early prethermal stage of matter evolution in ultrarelativistic heavy ion
collisions is discussed. Our results can be useful for understanding under what
conditions isotropization of the quark-gluon plasma in ultrarelativistic heavy
ion collisions can be reached within phenomenologically observed time scales.
