激光间接驱动柱几何内界面减速段的流体力学不稳定性实验研究

Experimental study on the hydrodynamic instability of the decelerated inner interface in indirect-driven cylindrical implosions

研究收缩几何下的流体力学不稳定性增长对于惯性约束聚变靶丸降低流体力学不稳定性增长和混合的优化设计具有重要的作用。在神光100 kJ激光装置上开展了辐射驱动柱几何内界面减速段的流体力学不稳定性实验,观测到模耦合现象,以及收缩几何独有的Bell-Plesset(BP)效应,理论预估BP效应导致的扰动增长与实验结果基本一致。实验中观察到驱动不对称性引入的2阶模扰动,M2不对称性约为11%,提出了通过增加黑腔长度来优化驱动不对称性的方法。柱几何流体力学不稳定性增长研究将有助于理解收缩几何效应在高能量密度条件下对流体力学不稳定性增长的影响,为优化惯性约束聚变靶丸设计提供帮助。

The investigation of hydrodynamic instability growth in convergent geometry is crucial for optimizing the design of inertial confinement fusion capsules,which aims to mitigate the growth of hydrodynamic instability and mixing.Experiments about the hydrodynamic instability of the decelerated inner interface in radiationdriven cylindrical implosions were conducted at 100 kJ laser facility.Mode coupling of perturbations and the Bell-Plesset(BP)effect unique to convergent geometry were observed.The theoretical predictions of the growth induced by the BP effect are consistent with the experimental results.Additionally,these experiments identified a second-order mode introduced by an M2 drive asymmetry.The drive asymmetry is about 11%.To mitigate the drive asymmetry,a method of extending the length of the hohlraum was proposed.Researches of the hydrodynamic instability in cylindrical geometry contribute to a better understanding of how convergent geometry affects hydrodynamic instability growth at high energy density,thereby aiding in optimizing the design of inertial confinement fusion capsules.