Non-linear characteristics of Rayleigh-Taylor instable perturbations

• 来源期刊: 力学学报（英文版）
• 年，卷（期）: 2008,（2）
• 页码范围: 143-149
• 页数: 7页
• 语种: 英文
• DOI: 10.1007/s10409-008-0135-9

摘要

The direct numerical simulation method is adopted to study the non-linear characteristics of Rayleigh-Taylor instable perturbations at the ablation front of a 200 μm planar CH ablation target. In the simulation, the classical electrical thermal conductivity is included, and NND differ-ence scheme is used. The linear growth rates obtained from the simulation agree with the Takabe formula. The ampli-tude distribution of the density perturbation at the ablation front is obtained for the linear growth case. The non-linear characteristics of Rayleigh-Taylor instable perturbations are analyzed and the numerical results show that the amplitude distributions of the compulsive harmonics are very different from that of the fundamental perturbation. The characteris-tics of the amplitude distributions of the harmonics and their fast growth explain why spikes occur at the ablation front.The numerical results also show that non-linear effects have relations with the phase differences of double mode initial perturbations, and different phase differences lead to varied spikes.