Tamagawa T, Hironaka Y, Kawasaki K, Tanaka D, Idesaka T, Ozaki N, Kodama R, Takizawa R, Fujioka S, Yogo A, Batani D, Nicolai Ph, Cristoforetti G, Koester P, Gizzi L A, Shigemori K
Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
Graduate School of Engineering and Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
Rev Sci Instrum. 2022 Jun 1;93(6):063505. doi: 10.1063/5.0089969.
The shock ignition (SI) approach to inertial confinement fusion is a promising scheme for achieving energy production by nuclear fusion. SI relies on using a high intensity laser pulse (≈10 W/cm, with a duration of several hundred ps) at the end of the fuel compression stage. However, during laser-plasma interaction (LPI), several parametric instabilities, such as stimulated Raman scattering and two plasmon decay, nonlinearly generate hot electrons (HEs). The whole behavior of HE under SI conditions, including their generation, transport, and final absorption, is still unclear and needs further experimental investigation. This paper focuses on the development of an experimental platform for SI-related experiments, which simultaneously makes use of multiple diagnostics to characterize LPI and HE generation, transport, and energy deposition. Such diagnostics include optical spectrometers, streaked optical shadowgraph, an x-ray pinhole camera, a two-dimensional x-ray imager, a Cu Kα line spectrometer, two hot-electron spectrometers, a hard x-ray (bremsstrahlung) detector, and a streaked optical pyrometer. Diagnostics successfully operated simultaneously in single-shot mode, revealing the features of HEs under SI-relevant conditions.
惯性约束聚变的冲击点火（SI）方法是一种很有前景的实现核聚变能源生产的方案。SI依赖于在燃料压缩阶段末期使用高强度激光脉冲（≈10 W/cm，持续时间为几百皮秒）。然而，在激光与等离子体相互作用（LPI）过程中，一些参数不稳定性，如受激拉曼散射和双等离子体衰变，会非线性地产生热电子（HEs）。在SI条件下HE的整体行为，包括它们的产生、输运和最终吸收，仍然不清楚，需要进一步的实验研究。本文重点介绍了一个用于与SI相关实验的实验平台的开发，该平台同时利用多种诊断手段来表征LPI以及HE的产生、输运和能量沉积。这些诊断手段包括光学光谱仪、条纹光学阴影图、X射线针孔相机、二维X射线成像仪、Cu Kα线光谱仪、两个热电子光谱仪、一个硬X射线（轫致辐射）探测器和一个条纹光学高温计。这些诊断手段在单次模式下成功同时运行，揭示了与SI相关条件下热电子的特征。
