The Study of Radiative Effects on Turbulent High Energy Density Plasmas

该项目旨在了解是否可以在实验室高能量密度等离子体中创建和理解湍流状态。高能量密度等离子体（HED）是一种由电子、离子和光子组成的热汤，它以一种极端的状态存在于我们的宇宙中，温度超过10,000 K，密度非常高。HED天体物理系统包括吸积现象，超新星残余物，超音速流出或射流，仅举几例。在天体物理学的尺度上，比如在超新星中，高能等离子体系统的大小可以达到数千英里。在实验室里，例如在一个聚变实验中，HED等离子体可以是十分之一厘米。本研究将研究实验室大小的高能等离子体中光子携带的强辐射对低压力和低密度等离子体典型的复杂流体状湍流特性的影响。更好地了解实验室大小的等离子体的这种基本行为可以为理解一般的HED等离子体提供信息。本文采用理论、计算和实验相结合的方法，研究了辐射对等离子体后期多模流体力学的影响。要做到这一点，首先，一个后期的，流体动力学不稳定的系统将被创建和观察。这将通过测量密度变化和多模扰动的不稳定增长的依赖性来完成，使用由国家点火设施和欧米茄激光设施正在进行的实验开发的技术。这些测量将使多维辐射流体动力学代码的验证成为可能，从而设计一个探索辐射对后期流体动力学过程演化影响的实验。

This project seeks to learn whether or not a turbulent state can be created and understood in a laboratory high energy density plasma. High-energy-density (HED) plasmas, a hot soup of electrons, ions and photons, exist throughout our universe in an extreme state with high temperatures of over 10,000 K and very high densities. HED astrophysical systems include accretion phenomena, supernovae remnants, and supersonic outflows or jets, to name a few. On the astrophysical scales, such as in supernovae, HED plasma systems can be thousands of miles in size. In the laboratory, in a fusion experiment for example, an HED plasma can be one tenth of a centimeter. This study will investigate the impacts of the strong radiation carried by photons in a laboratory-sized HED plasma on the properties of complex fluid-like turbulence typical of plasmas at lower pressures and densities. Better understanding of this fundamental behavior in laboratory-sized plasmas can inform understanding of HED plasmas in general. The aim of this work is to investigate the effect of radiation on late-time, multi-mode hydrodynamics of an HED plasma using an integrated approach combining theory, computation and experiments. To do so, first, a late-time, hydrodynamically unstable system will be created and observed. This will be accomplished by measuring the dependence of the unstable growth of density variations and multimode perturbations, using techniques developed by the team for ongoing experiments at the National Ignition Facility and the Omega Laser Facility. These measurements will enable validation of multidimensional radiation hydrodynamics codes to design an experiment that explores the effect of radiation on the evolution of late-time hydrodynamic processes.