激光直接加热自背光法辐射不透明度测量方法探索

本文提出一种基于单束激光直接加热多层平面靶开展 稠密等离子体辐射不透明度特性研究的靶物理设计并对其进行了实验验证. 在XG-II激光装置上, 采用三倍频束匀滑激光辐照Au/CH/Al/CH多层平面靶产生背光源和Al样品等离子体, 通过观测背光源经样品等离子体衰减后的透过谱得到样品等离子体的辐射吸收性质. 采用Multi-1D程序对激光加热多层靶进行了辐射流体力学数值模拟, 给出了样品等离子体状态及其时间演化过程. 利用细致谱项模型 (DTA) 对实验测量的Al等离子体吸收谱进行理论分析, 表明等离子体温度在20–70 eV之间, 该结果与辐射流体力学模拟结果基本一致. 关键词： 吸收光谱 自背光 激光等离子体

Investigations on radiative opacity measurement by the method of direct laser-heating and self-backlighting

A target designed for opacity studies of dense plasmas by laser direct heating and self-backlighting technique was presented and tested. The backlight source and sample plasma were generated by directing a frequency-tripled Nb-glass laser onto an Au/CH/Al/CH multilayer target on the XG-II laser facility, and the absorption of the sample plasma was obtained by measuring the attenuated backlight spectrum of the sample plasma. One-dimensional radiative hydrodynamic code Multi-1D was used to simulate the laser heating of the multilayer target, and the temperature and density profiles in the target were given. Experimental data were compared with the theoretically calculated spectra using the detailed-term-accounting model, which showed a temperature range from 20 eV to 70 eV in the sample plasma, a result in quite good agreement with the Multi-1D simulations.
Keywords： absorption spectroscopy self-backlight laser-produced plasma