冲击波波后辐射效应对Richtmyer-Meshkov不稳定性增长影响的实验研究  

Understanding effects of radiation from radiative shock on Richtmyer-Meshkov instability

作　　者：袁永腾[1] 涂绍勇[1] 尹传盛[1] 李纪伟[2] 戴振生[2] 杨正华[1] 侯立飞[1] 詹夏宇[1] 晏骥[1] 董云松[1] 蒲昱东[1] 邹士阳[2] 杨家敏[1] 缪文勇[1] Yuan Yong-Teng;Tu Shao-Yong;Yin Chuan-Sheng;Li Ji-Wei;Dai Zhen-Sheng;Yang Zheng-Hua;Hou Li-Fei;Zhan Xia-Yu;Yan Ji;Dong Yun-Song;Pu Yu-Dong;Zou Shi-Yang;Yang Jia-Min;Miao Wen-Yong(Research Center of Laser Fusion,China Academy of Engineering Physics,Mianyang 621900,China;Institute of Applied Physics and Computational Mathematics,Beijing 100088,China)

机构地区：[1]中国工程物理研究院激光聚变研究中心,绵阳621900 [2]北京应用物理与计算数学研究所,北京100088

出　　处：《物理学报》2021年第20期157-166,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11705179,11905205);科学挑战计划(批准号:TZ2016005)资助的课题。

摘　　要：辐射冲击波波后物质具有辐射属性,它通过扰动界面引起的Richtmyer-Meshkov(RM)不稳定性的增长有别于通常的冲击波.在高功率激光装置上开展冲击波波后辐射效应对界面不稳定性增长影响的实验研究,认识波后辐射对界面增长的影响过程及规律,有助于提高高能量密度条件下RM不稳定性演化规律的认识水平及预测能力.基于神光Ⅲ原型高功率激光装置,设计并开展了两种激光驱动条件下的界面流体力学不稳定性实验,研究波后辐射效应对界面RM不稳定性增长的影响.实验中在较高功率密度驱动条件下CHBr扰动样品未见明显的扰动增长,结合模拟分析发现较高功率密度条件下辐射前驱波波阵面和冲击波波阵面明显分离,辐射前驱波在冲击波到达扰动界面前烧蚀扰动界面,改变了界面的初始状态,界面不稳定性增长过程中密度梯度的增大和界面Atwood数的减小抑制了界面RM不稳定性的增长.Radiative shocks are ubiquitous in stellar environments and are characterized by high temperature plasma emitting a considerable fraction of their energy as radiation.Radiative shocks occur commonly in nature,especially in astronomical systems and inertial confinement fusion.The study of the effects of radiation on Richtmyer-Meshkov(RM)instability will improve our ability to understand and predict the evolution of RM instability under high energy density conditions.A few experiments have been performed to compare the radiative case with the non-radiative case in Rayleigh-Taylor(RT)instability,thereby studying how the radiative effects change the evolution of RT instability,but the interplay between RM instability and radiative shock has been studied rarely.This paper reports mainly the role of radiation in the changing of the RM instability.Two experiments are performed at ShenguangⅢprototype laser facility,the RM instability growth data are obtained by varying the laser intensity.The laser intensity for high-drive experiment is approximately 60%greater than that for lowdrive experiment.The target consists of a multiple layer in the axial direction,in which the first layer is a15μm-thick CH sample serving as an ablator,followed by a 10μm-thick aluminum used as a shield layer to prevent the preheat effect.The next layer is a 350-μm-thick SiO2 foam,which is used as a material to produce a radiative shock.The last layer is the CH perturbed sample.There is a sinusoidal perturbation on the surface of CH sample which is adjacent to the SiO2 foam.The target is irradiated by four overlapping laser beams,and the laser beams produce a large pressure that drives a shock wave,whose velocity can be changed by varying the laser intensity,into the target package.In the experiments,shock-generated radiative fluxes first ablate the unstable interface which the shock has not passed through,then the shock transmits the unstable interface to produce the RM instability.The images of unstable interface are captured using side-on

关 键 词：辐射冲击波 RICHTMYER-MESHKOV不稳定性 密度梯度尺度 烧蚀速度 Atwood数 

分 类 号：TN24[电子电信—物理电子学]