University of California San Diego, La Jolla, California 92093, USA.
Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA.
Rev Sci Instrum. 2023 Feb 1;94(2):023508. doi: 10.1063/5.0135265.
We report the first optical Thomson scattering measurements inside a high electron temperature (≳1 keV) and moderate electron density (mid 10 cm) plasma. This diagnostic has been built to provide critical plasma parameters, such as electron temperature and density, for Advanced Research Projects Agency-Energy-supported fusion-energy concepts. It uses an 8 J laser at 532 nm in 1.5 ns to measure the high frequency feature of the Thomson scattering profile at 17 locations along the probe axis. It is able to measure electron density from 5 × 10 cm to several 10 cm and electron temperatures from tens of eV to several keV. Here, we describe the design, deployment, and analysis on the sheared flow stabilized Z-pinch machine at Zap Energy named FuZE. The probe beam is aimed at an axial distance of 20 cm from the central electrode and is timed within the temporal envelope of neutron emission. The high temperature and moderate density plasmas generated on FuZE lie in an unconventional regime for Thomson scattering as they are between tokamaks and laser-produced plasmas. We described the analysis considerations in this regime, show that the electron density was below 5 × 10 cm at all times during these measurements, and present a sample shot where the inferred electron temperature varied from 167 ± 16 eV to 700 ± 85 eV over 1.6 cm.
我们报告了首例在高电子温度（≳1 keV）和中等电子密度（中 10 cm）等离子体内进行的光学汤姆逊散射测量。该诊断方法旨在为高级研究计划署能源支持的聚变能概念提供关键的等离子体参数，如电子温度和密度。它使用 532nm 的 8J 激光在 1.5ns 内测量探针轴线上 17 个位置的汤姆逊散射谱的高频特征。它能够测量 5×10 cm 到几个 10 cm 的电子密度和几十电子伏到几 keV 的电子温度。在这里，我们描述了在 Zap Energy 名为 FuZE 的剪切流稳定 Z 箍缩机上的设计、部署和分析。探针束瞄准距离中心电极 20 cm 的轴向距离，并在中子发射的时间包络内定时。在 FuZE 上产生的高温和中等密度等离子体处于汤姆逊散射的非常规区域，因为它们处于托卡马克和激光产生等离子体之间。我们描述了该区域的分析考虑因素，表明在这些测量过程中的所有时间，电子密度都低于 5×10 cm，并展示了一个示例，其中推断的电子温度在 1.6cm 内从 167±16 eV 变化到 700±85 eV。
