Multimode Rayleigh-Taylor Experiments on Nova

Multimode Rayleigh-Taylor experiments have been conducted with planar CH(Br) foils accelerated by x-ray ablation. The perturbations consisted of the superposition of either two or eight sinusoids. In the linear regime the modes grow independently, but become coupled in the nonlinear regime, leading to the appearance of $k_i\pm k_j$ "beat" modes. This results in a redistribution of the perturbation into a broader Fourier spectrum causing a change of shape: bubbles become broader and spikes narrower. The overall size of the perturbation is not significantly altered.