Statistical approach of weakly nonlinear ablative Rayleigh-Taylor instability

A weakly nonlinear model is proposed for the Rayleigh-Taylor instability in presence of ablation and thermal transport. The nonlinear effects for a single-mode disturbance are computed, included the nonlinear correction to the exponential growth of the fundamental modulation. Mode coupling in the spectrum of a multimode disturbance is thoroughly analyzed by a statistical approach. The exponential growth of the linear regime is shown to be reduced by the nonlinear mode coupling. The saturation amplitude is around 0.1 lambda for long wavelengths, but higher for short instable wavelengths in the ablative regime. (C) 2005 American Institute of Physics.