  We extend the ideas of Kolmogorov theory on symmetries of turbulent dynamics
to analyze invariants, scaling and spectra of unsteady turbulent mixing induced
by the Rayleigh-Taylor instability. Time- and scale-invariance of the rate of
momentum loss leads to non-dissipative momentum transfer between the scales, to
and power-law scale-dependencies of the velocity and Reynolds number and
spectra distinct from Kolmogorov, and sets the viscous and dissipation scales.
Turbulent mixing exhibits more order compared to isotropic turbulence.
Mechanisms of flow regularization are discussed.
