锡-泡沫界面不稳定性增长与混合实验研究  

Instability Growth of Tin-Foam Interface and Mixing Experiment

作　　者：税敏[1] 杨曦[2] 于明海 吴玉迟[1] 张天奎[1] 赵永强[1] 席涛[1] 辛建婷[1] 杨雷[1] 何卫华[1] 储根柏[1] 谷渝秋[2] 刘旭东[2] Shui Min;Yang Xi;Yu Minghai;Wu Yuchi;Zhang Tiankui;Zhao Yongqiang;XiTao;Xin Jianting;Yang Lei;He Weihua;Chu Genbai;GuYuqiu;Liu Xudong(Science and Technology on Plasvia Physics Laboratory,Laser Fusion Research Center,China Academy of Engineering Physics,Mianyang,Sichuan 621900,China;Laser Fusion Research Center,China Academy of Engineering Physics,Mianyang,Sichuan 621900,China)

机构地区：[1]中国工程物理研究院激光聚变研究中心等离子体物理重点实验室,四川绵阳621900 [2]中国工程物理研究院激光聚变研究中心,四川绵阳621900

出　　处：《中国激光》2021年第7期66-74,共9页Chinese Journal of Lasers

摘　　要：强激光驱动的衰减冲击波作用下的界面不稳定性增长与混合是冲击压缩科学与工程研究领域的前沿和热点问题。在锡-泡沫界面(Atwood数A为-0.87)预制单模正弦扰动(kAη_(0)=0.82,其中η_(0)为初始扰动振幅,k为波数),采用高时空分辨的X光侧向透视照相技术研究激光加载产生的衰减冲击波作用下的界面不稳定性增长与混合。通过改变加载压强,研究材料强度对界面不稳定性增长与混合的影响。实验获得了不同时刻高对比度的界面不稳定性增长与混合面密度图像,冲击熔化压强点和卸载熔化压强点附近的尖钉形态和演化过程有明显差异,这表明锡材料强度对扰动增长速率及混合形态有重要影响。Objective Richtmyer-Meshkov instability arises when a shock wave encounters an interface between two materials of different densities.As instability develops through linear regime to nonlinear regime,mixing between two materials occurs and grows.The study of interface instability and mixing is relevant and of significant interest due to its promising application in many studies and engineering fields,such as phase transformations,multi-phase flow,and dynamic damage.Generally,hydrodynamic instabilities are studied under liquid conditions in which the materials have been shocked to liquid.Meanwhile,instability in solids is governed by their elastic and plastic properties(strength),and this area is attracting much interest presently due to its promising applications in investigating the constitutive properties of matter.Usually,a laser pulse ablation produces an unsupported shock in a material,and Rayleigh-Taylor instability(RTI)is induced due to the interface deceleration after the shock transit.In this study,we investigate the instability and mixing between the tin and polymer foam under unsupported shock loading via nanosecond laser ablation.The loading pressure is changed to evaluate the influence of strength on the instability growth and mixing characteristic via high-energy radiography.We hope the experimental results can improve the understanding of the issue and provide help for further studies.Methods Tin and polymer foam with initial single-mode sinusoidal interface perturbation(Atwood number A=-0.87,kAη_(0)=0.82)are employed in this study.A nanosecond laser pulse after the continuum phase plate of 2 mm diameter is focused on the tin surface,and an unsupported shock is produced at the tin-polymer foam interface.Another picosecond laser ablates the golden wire and produces several high-energy X-ray images,which are used to diagnose the instability and mixing via side-on radiography.The radiographs are recorded by the image plate fixed on the rear side of the high-energy X-ray camera.The evolution images of

关 键 词：材料 成像系统 X光成像 界面不稳定性 混合 微喷射 

分 类 号：O436[机械工程—光学工程]