Coupled model analysis of the ablitive Rayleigh-Taylor instability


 The weakly nonlinear stage of the ablative Rayleigh-Taylor instability (ARTI) is investigated by the expanded hydrodynamic equations in which the third-order corrections of the two-mode perturbations are considered. In the present coupling model, two linear perturbations are simultaneously added near the ablation front at the initial moment, and we have derive the first three coupling harmonics. Furthermore, the coupling model analysis is studied via direct numerical simulation as well. When the original two fundamental modes are always dominant over other modes, the time evolution of the density amplitudes for these modes agrees well with the results of direct numerical simulation. It is found that the harmonics are stabilized by the mode coupling effects, and the long wavelength mode of the fundamental modes tends to dominate the growth of the ARTI. Two-mode coupling is one of restriction factors for the realization of controlled inertial confinement fusion (ICF). Therefore, the coupling harmonics excited by two-mode perturbations have good application potentials and are worth for further study.