Comprehensive Diagnosis of Growth Rates of the Ablative Rayleigh-Taylor Instability

The growth rate of the ablative Rayleigh-Taylor instability is approximated by γ=√kg/(1+kL)-βk ̇ m/ρₐ, where k is the perturbation wave number, g the gravity, L the density scale length, ̇ m the mass ablation rate, and ρₐ the peak target density. The coefficient β was evaluated for the first time by measuring all quantities of this formula except for L, which was taken from the simulation. Although the experimental value of β=1.2±0.7 at short perturbation wavelengths is in reasonably good agreement with the theoretical prediction of β=1.7, it is found to be larger than the prediction at long wavelengths.