Ablation effects in weakly nonlinear stage of the ablative Rayleigh-Taylor instability

Weakly nonlinear stage of the ablative Rayleigh-Taylor instability has been studied by the perturbation theory. Mode coupling of linear growing waves with wave numbers κA and κB drives new excited waves with wave numbers κO (=κA±κB, 2κA, 2κB). We have investigated time evolution of the excited waves and found that the ablation effect plays an important role even in the nonlinear stage to reduce amplitude of the excited waves. Differences between an ablation surface and a classical contact surface have been discussed. Dependence of the excited wave amplitude on the wavenumber κO, the ablation velocity υa, and the effective gravity g is also investigated. (Author)