Studies of laser-plasma interaction physics with low-density targets for direct-drive inertial confinement fusion on the Shenguang III prototype
Studies of laser-plasma interaction physics with low-density targets for direct-drive inertial confinement fusion on the Shenguang III prototype
复制标题
神光三号原型机上直驱惯性约束聚变低密度靶激光-等离子体相互作用物理研究
DOI：
10.1063/5.0023006
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发表时间：
2021-03-01
影响因子：
5.1
通讯作者：
Weber, S.
中科院分区：
文献类型：
--
作者：
Tikhonchuk, V. T.;Gong, T.;Weber, S.
在神光III原型激光装置上，在与惯性约束聚变设计有关的条件下，研究了激光-等离子体相互作用的物理学。一个亚毫米大小的低密度热等离子体是由四个高能量（3.2千焦）激光束电离的低密度塑料泡沫。相互作用光束发射的延迟允许在等离子体演化的不同阶段的参数不稳定性的激发的评价。多种诊断用于等离子体表征、散射辐射和加速电子。实验结果进行了分析与辐射流体动力学模拟，考虑到泡沫电离和均匀化。测得的受激拉曼散射的水平几乎是一个数量级大于在同一装置上的气囊和黑腔的实验中测得的，可能是因为更大的等离子体密度。显着的放大，实现了高强度散斑，表明实施激光时间平滑技术的重要性与控制激光传播和吸收的大带宽。
The physics of laser-plasma interaction is studied on the Shenguang III prototype laser facility under conditions relevant to inertial confinement fusion designs. A sub-millimeter-size underdense hot plasma is created by ionization of a low-density plastic foam by four high-energy (3.2 kJ) laser beams. An interaction beam is fired with a delay permitting evaluation of the excitation of parametric instabilities at different stages of plasma evolution. Multiple diagnostics are used for plasma characterization, scattered radiation, and accelerated electrons. The experimental results are analyzed with radiation hydrodynamic simulations that take account of foam ionization and homogenization. The measured level of stimulated Raman scattering is almost one order of magnitude larger than that measured in experiments with gasbags and hohlraums on the same installation, possibly because of a greater plasma density. Notable amplification is achieved in high-intensity speckles, indicating the importance of implementing laser temporal smoothing techniques with a large bandwidth for controlling laser propagation and absorption.