中文摘要：

使用二维辐射多群扩散流体力学程序LARED？S对点火靶内爆进行大规模数值模拟，同时考虑低阶辐射驱动不对称性和中高阶的表面粗糙度。计算结果表明：靶丸内爆流场不仅出现严重的低阶模面密度扰动，同时生成大幅度的尖钉与气泡结构；呈现明显的扰动模耦合效应，模耦合生成的扰动增长幅度与理论公式在一定时间内较好地吻合。在内爆减速阶段，扰动增长发展到强非线性阶段，模耦合效应使得扰动频谱分布变宽；同时芯部的涡流使得靶壳的尖钉弯曲，内爆流场出现明显的湍流混合现象。模耦合效应与湍流混合极大地降低了内爆性能，导致点火失败。

英文摘要：

We perform 2D ignition capsule implosion simulation by a 2D multi-group radiation diffusion hydrodynamic code LARED-S which simultaneously simulates radiation drive asymmetry and outer surface roughness. Implosion flow field shows large-amplitude spikes and bubbles as well as a significant low-mode shell areal density asymmetry. Amplitudes of modes generated by mode coupling are in good agreement with analytic mode coupling equation until perturbation amplitude of fundamental mode L24 is greater than nonlinear saturation amplitude. In deceleration phase, perturbation growth is in strong nonlinear phase, and strong mode coupling effects broaden mode distribution. High-density spikes are bent by vortex flow. Mode coupling degrades greatly implosion performance, leading to ignition failure. Further simulations of mode coupling between low-mode drive asymmetry and capsule surface roughness is critical for understanding influences of hydrodynamic instabilities on ignition capsule implosion.