Study of methods to reduce SRS of inner beams in ICF ignition hohlraums
-
摘要: 激光等离子体相互作用(LPI)是制约在美国国家点火装置(NIF)上实现间接驱动惯性约束聚变的关键问题之一。LPI的激发不仅依赖于激光束功率密度与光束品质,还强烈依赖于光束所经过的等离子体状态。模拟显示,内环激光通道上靠近腔壁的He等离子体是受激拉曼散射(SRS)产生的主要区域。通过改变黑腔设计参数(包括构型、尺寸和填充物材料等)可以一定程度优化特定区域的等离子体状态,进而抑制LPI的产生。据此,提出了使用大黑腔高激光能量和改变填充气体组分两条控制SRS增长的技术路线。线性分析表明,两条技术路线效果明显,可分别将SRS峰值增益降低70%与63%。
-
关键词:
- 间接驱动惯性约束聚变 /
- 激光等离子体相互作用 /
- 等离子体定标关系 /
- 点火黑腔设计
Abstract: Laser-plasma interactions (LPI) is very important to the success of indirect-drive inertial confinement fusion on NIF. LPI is related not only to laser intensity or laser quality, but also to the plasma state on laser path. Simulations show that the He plasma near gold wall in inner cone laser path is prone to produce SRS in ignition hohlraums. The plasma state can be optimized by changing hohlraum parameters to depress LPI. Accordingly, two methods (using large hohlraums and high laser energy, changing the filling gases) are proposed to reduce SRS gain at this position. Simulations show the peak SRS gain is reduced by 70% and 63% respectively by these two methods.
点击查看大图
计量
- 文章访问数: 933
- HTML全文浏览量: 143
- PDF下载量: 226
- 被引次数: 0