Saturation of zonal flow
¥Different expressions for random 3-wave (low γ) and coherent (high γ) regimes
¥Intermediate range with Uzf ~ V*.
¥Only weak ZF damping dependence (important γ is at ρk~1).
¥ No oscillatory behaviour. ZF cannot fall below the crit value because itÕd be immediately pumped due to renewed instability.