Investigation on laser plasma instability of the outer ring beams on SGIII laser facility
Investigation on laser plasma instability of the outer ring beams on SGIII laser facility
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DOI：
10.1063/1.5087936
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发表时间：
2019-09
期刊：
影响因子：
1.6
通讯作者：
L. Hao;Dong Yang;Xin Li;Zhi-chao Li;Yao-yuan Liu;H. Cai;Zhanjun Liu;P. Gu;T. Xu;
中科院分区：
文献类型：
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作者：
L. Hao;Dong Yang;Xin Li;Zhi-chao Li;Yao-yuan Liu;H. Cai;Zhanjun Liu;P. Gu;T. Xu;
为了研究激光束以大角度入射的六面激光间接驱动黑腔和三轴圆柱形黑腔的激光等离子体不稳定性。根据SGIII激光装置现有的激光器布置条件，首次设计并实现了圆柱形黑腔中只有外光束的LPI实验。受激布里渊后向散射（SBS）是实验中发现的具有高瞬时反射率的主要不稳定性。在SBS的时间分辨光谱中得到了一个典型的特征，在不同的相互作用光束的激光强度保持相似。结合基于射线追踪模型的HLIP程序，对实验数据进行了流体力学模拟分析。通过对实验数据的分析，指出气体与Au界面区域的混合对SBS的影响是重要的，这表明在流体动力学模拟中需要填充气体与黑腔壁高Z等离子体的混合模型。本文还讨论了受激布里渊散射的非线性饱和问题和平滑光束问题。为了研究激光束以大角度入射的六面激光间接驱动黑腔和三轴圆柱形黑腔中的激光等离子体不稳定性，我们对离子扩散效应和平滑光束的有效考虑为改进现有的光线追迹方法提供了实用的途径。根据SGIII激光装置现有的激光器布置条件，首次设计并实现了圆柱形黑腔中只有外光束的LPI实验。受激布里渊后向散射（SBS）是实验中发现的具有高瞬时反射率的主要不稳定性。在SBS的时间分辨光谱中得到了一个典型的特征，在不同的相互作用光束的激光强度保持相似。结合基于射线追踪模型的HLIP程序，对实验数据进行了流体力学模拟分析。通过对实验数据的分析，认为气体与Au界面区域的混合对SBS的形成起着重要作用，这表明了研究SBS的必要性。
In order to study the laser plasma instabilities (LPIs) in the context of some novel six-side laser-driven indirect designs like the six-cylinder-port hohlraum and the three-axis cylindrical hohlraum, where the laser beams inject in hohlraum with a large angle. LPI experiments in cylindrical hohlraum with only outer beams were designed and performed based on the current laser arrangement condition of SGIII laser facility for the first time. Stimulated Brillouin backscatter (SBS) was found to be the dominant instability with high instantaneous reflectivity in experiments. A typical feature was obtained in the time-resolved spectra of SBS, which maintained similar for different laser intensities of the interaction beam. The experimental data are analyzed by the hydrodynamic simulations combined with HLIP code, which is based on the ray-tracing model. By analysis of experimental data, it is argued that the mixture of gas and Au in the region of their interface is important to SBS, which indicates the need for the mixture model between the filled gas and the high Z plasma from hohlraum wall in the hydrodynamic simulations. Nonlinear saturation of SBS as well as the smoothed beam are also discussed here. Our effective considerations of the ions pervasion effect and the smoothed beam provide utilitarian ways for improvement of the current ray-tracing method.In order to study the laser plasma instabilities (LPIs) in the context of some novel six-side laser-driven indirect designs like the six-cylinder-port hohlraum and the three-axis cylindrical hohlraum, where the laser beams inject in hohlraum with a large angle. LPI experiments in cylindrical hohlraum with only outer beams were designed and performed based on the current laser arrangement condition of SGIII laser facility for the first time. Stimulated Brillouin backscatter (SBS) was found to be the dominant instability with high instantaneous reflectivity in experiments. A typical feature was obtained in the time-resolved spectra of SBS, which maintained similar for different laser intensities of the interaction beam. The experimental data are analyzed by the hydrodynamic simulations combined with HLIP code, which is based on the ray-tracing model. By analysis of experimental data, it is argued that the mixture of gas and Au in the region of their interface is important to SBS, which indicates the need fo...