  In this study we model early times dynamics of the system produced in
relativistic heavy ion collisions by an initial color electric field which then
decays to a plasma by the Schwinger mechanism, coupling the dynamical evolution
of the initial color field to the dynamics of the many particles system
produced by the decay. The latter is described by relativistic kinetic theory
in which we fix the ratio $\eta/s$ rather than insisting on specific
microscopic processes. We study isotropization and thermalization of the system
produced by the field decay for a static box and for a $1+1$D expanding
geometry. We find that regardless of the viscosity of the produced plasma, the
initial color electric field decays within $1$ fm/c; however in the case
$\eta/s$ is large, oscillations of the field are effective along all the entire
time evolution of the system, which affect the late times evolution of the
ratio between longitudinal and transverse pressure. In case of small $\eta/s$
($\eta/s\lesssim0.3$) we find $\tau_{isotropization}\approx 0.8$ fm/c and
$\tau_{thermalization}\approx 1$ fm/c in agreement with the common lore of
hydrodynamics. Moreover we have investigated the effect of turning from the
relaxation time approximation to the Chapman-Enskog one: we find that this
improvement affects mainly the early times evolution of the physical
quantities, the effect being milder in the late times evolution.
