Nonlinear evolution of the ablative Rayleigh-Taylor instability with preheating

الأصل · EN

Evolution of the single-mode ablative Rayleigh-Taylor instability in the presence of preheating is investigated numerically. It is found that the instability evolution depends strongly on the preheating length L in front of the ablation-front interface. For weak preheating (L/L SH≤ f₀, where L SH is the Spitzer-Harm length and f₀ 20 is a critical value), the linear growth rate has a sharp maximum and a secondary spike-bubble structure is generated. Interaction of this growing structure with the master spike-bubble leads to rupture of the latter. However, for strong preheating (L/L SH>20), the linear growth rate has no sharp maximum and no secondary spike-bubble is generated. Instead, the master spike-bubble evolves into an elongated jet. These results are interpreted in terms of the evolution and interaction of the instability-generated harmonic modes.