单束激光脉冲俘获及放大机理的理论分析与数值模拟研究

Theory and simulation of laser pulse trapping and amplifying in the interaction with a thin foil and a solid target

本文提出用固体靶前放置薄膜靶来实现激光场放大的新方案,研究了针对单束激光脉冲条件的俘获及放大机理.理论模型与数值模拟均表明入射激光能量可以部分地以驻波形式驻留在靶间区域并得到有效放大.研究表明在入射激光光压、俘获激光光压和电荷分离场的共同作用下,薄膜靶电子层压缩和膨胀是能量积累存在反复振荡过程的直接原因,经过振荡后激光脉冲得到稳定俘获.

In this paper we suggest a simple structure consisting of a thin foil and a solid target with specified gap width to achieve the laser-field amplification,and study the trapping process of a single pulse.Both the theoretical and simulation results show that the EM fields are trapped as standing waves between two layers of enhanced electron density.The laser energy can be accumulated like the accumulation of charges in capacitor,a stably trap is reached after several oscillations.The compressing and the expanding of the electron layer,generated by the incident light pressure,the trapped light pressure and the charge electrostatic fields,are the direct reason for the energy oscillations.