Levy M C, Ryutov D D, Wilks S C, Ross J S, Huntington C M, Fiuza F, Martinez D A, Kugland N L, Baring M G, Park H-S
Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
Rev Sci Instrum. 2015 Mar;86(3):033302. doi: 10.1063/1.4909536.
Proton radiography is a useful diagnostic of high energy density (HED) plasmas under active theoretical and experimental development. In this paper, we describe a new simulation tool that interacts realistic laser-driven point-like proton sources with three dimensional electromagnetic fields of arbitrary strength and structure and synthesizes the associated high resolution proton radiograph. The present tool's numerical approach captures all relevant physics effects, including effects related to the formation of caustics. Electromagnetic fields can be imported from particle-in-cell or hydrodynamic codes in a streamlined fashion, and a library of electromagnetic field "primitives" is also provided. This latter capability allows users to add a primitive, modify the field strength, rotate a primitive, and so on, while quickly generating a high resolution radiograph at each step. In this way, our tool enables the user to deconstruct features in a radiograph and interpret them in connection to specific underlying electromagnetic field elements. We show an example application of the tool in connection to experimental observations of the Weibel instability in counterstreaming plasmas, using ∼10(8) particles generated from a realistic laser-driven point-like proton source, imaging fields which cover volumes of ∼10 mm(3). Insights derived from this application show that the tool can support understanding of HED plasmas.
质子射线照相术是一种用于诊断高能量密度（HED）等离子体的有用方法，目前正处于积极的理论和实验研究阶段。在本文中，我们描述了一种新的模拟工具，该工具将实际的激光驱动点状质子源与任意强度和结构的三维电磁场相互作用，并合成相关的高分辨率质子射线照片。该工具的数值方法捕捉了所有相关的物理效应，包括与焦散形成相关的效应。电磁场可以以简化的方式从粒子模拟或流体动力学代码中导入，并且还提供了一个电磁场“基元”库。后一种功能允许用户添加一个基元、修改场强、旋转基元等等，同时在每一步快速生成高分辨率射线照片。通过这种方式，我们的工具使用户能够解构射线照片中的特征，并将它们与特定的潜在电磁场元素联系起来进行解释。我们展示了该工具在与反向流动等离子体中韦贝尔不稳定性的实验观测相关的一个示例应用，使用了从实际的激光驱动点状质子源产生的约10^8个粒子，对覆盖约10立方毫米体积的场进行成像。从这个应用中获得的见解表明，该工具可以支持对高能量密度等离子体的理解。
