  Motivated by the boost-invariant Glasma state in the initial stages in
heavy-ion collisions, we perform classical-statistical simulations of SU(2)
gauge theory in 2+1 dimensional space-time both with and without a scalar field
in the adjoint representation. We show that irrespective of the details of the
initial condition, the far-from-equilibrium evolution of these highly occupied
systems approaches a unique universal attractor at high momenta that is the
same for the gauge and scalar sectors. We extract the scaling exponents and the
form of the distribution function close to this non-thermal fixed point. We
find that the dynamics are governed by an energy cascade to higher momenta with
scaling exponents $\alpha = 3\beta$ and $\beta = -1/5$. We argue that these
values can be obtained from parametric estimates within kinetic theory
indicating the dominance of small momentum transfer in the scattering
processes. We also extract the Debye mass non-perturbatively from a
longitudinally polarized correlator and observe an IR enhancement of the scalar
correlation function for low momenta below the Debye mass.
