Exploring the Atwood-number dependence of the highly nonlinear Rayleigh-Taylor instability regime in high-energy-density conditions
Exploring the Atwood-number dependence of the highly nonlinear Rayleigh-Taylor instability regime in high-energy-density conditions
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探索高能量密度条件下高度非线性瑞利-泰勒不稳定状态的阿特伍德数依赖性
DOI：
10.1103/physreve.104.045213
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发表时间：
2021
影响因子：
2.4
通讯作者：
Casner A.
中科院分区：
文献类型：
--
作者：
Rigon G.;Albertazzi B.;Mabey P.;Michel Th.;Falize E.;Bouffetier V.;Ceurvorst L.;Masse L.;Koenig M.;Casner A.
我们的实验研究的晚期，高度非线性制度的瑞利-泰勒不稳定性在减速阶段。在LULI 2000激光器上进行了一系列激光驱动实验，通过调节减速介质密度来改变初始Atwood数。高功率激光器用于直接驱动配置，以使固体目标运动。它的后侧，最初拥有一个二维加工的正弦扰动，膨胀和减速成泡沫，导致瑞利-泰勒不稳定的情况。通过时间分辨X射线照相术测量界面位置和形态。我们开发了一个简单的阿特伍德依赖模型描述的运动的减速界面，从它的加速历史。测得的振幅的不稳定性，或混合区的宽度，然后与后期的加速度依赖瑞利-泰勒不稳定性模型进行比较。这个经典模型的缺点，当应用到高能量密度的条件下，示出。这使人们对它们在存在冲击波的系统中的用途产生了疑问，例如在实验室天体物理学或惯性约束聚变中发现的系统。
We experimentally study the late-time, highly nonlinear regime of the Rayleigh-Taylor instability in a decelerating phase. A series of laser-driven experiments is performed on the LULI2000 laser, in which the initial Atwood number is varied by adjusting the decelerating medium density. The high-power laser is used in a direct drive configuration to put into motion a solid target. Its rear side, which initially possesses a two-dimensional machined sinusoidal perturbations, expands and decelerates into a foam leading to a Rayleigh-Taylor unstable situation. The interface position and morphology are measured by time-resolved x-ray radiography. We develop a simple Atwood-dependent model describing the motion of the decelerating interface, from which its acceleration history is obtained. The measured amplitude of the instability, or mixing zone width, is then compared with late-time acceleration-dependent Rayleigh-Taylor instability models. The shortcomings of this classical model, when applied to high-energy-density conditions, are shown. This calls into question their uses for systems, where a shock wave is present, such as those found in laboratory astrophysics or in inertial confinement fusion.