Organized by
Department of Mathematics
Department of Physics
Joint Research Institute for Applied Mathematics

Nonlinear evolution of ablative Rayleigh-Taylor instability

Professor Xian-Tu He

Institute of Applied Physics and Computational Mathematics, China


Date: 12 April 2010 (Monday)

4:00pm - 5:00pm (Preceded by Reception at 3:30pm)

RRS905, Sir Run Run Shaw Building,
Ho Sin Hang Campus,
Hong Kong Baptist University


Evolution of the ablative single-mode Rayleigh-Taylor instability in the present of preheating is investigated numerically. It is found that the evolution depends strongly on the preheating length L in front of the ablation-front interface. For weak preheating (L/L_{SH} <= f_0, where LSH is the Spitzer-Harm length and f_0 ~ 20 is a critical value), the linear growth rate has a sharp maximum, and a secondary spike-bubble pattern is generated. Interaction of the growing secondary pattern with the master spike-bubble pattern leads eventually to rupture of the latter. However, for strong preheating (L/L_{SH} > 20), the linear growth rate has no sharp maximum and there is no secondary spike-bubble pattern. Instead, the master spike-bubble pattern evolves into an elongated jet. These results are interpreted in terms of the evolution and interaction of the instability generated harmonic modes.




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