软X射线激光汤姆逊散射实验尝试

汤姆逊散射是诊断高温稠密等离子体状态参数的重要方法之一, 受到广泛的关注. 但是目前用于进行汤姆逊散射的探针光波长多局限于可见光或紫外光, 能够诊断的区域电子密度远低于驱动激光的临界密度. 相比较而言, 以软X射线激光作为探针, 有希望诊断更高密度区域的等离子体. 利用“神光Ⅱ”高功率激光装置产生的类氖锗软X射线激光作为探针, 开展了软X射线激光汤姆逊散射实验的尝试. 根据散射的条件, 分别进行了非相干散射和相干散射的实验, 但均未能获得明显的散射谱. 理论分析表明, 主要原因可能是实验中作为探针的类氖锗软 X射线激光的聚焦功率密度不够, 通过优化实验条件, 有希望在今后的研究中获得相干汤姆逊散射的结果. 关键词： 等离子体诊断 软X 射线激光 汤姆逊散射

An experimental attempt to produce Thomson scattering with soft X-ray lasers

Thomson scattering is one of the important methods of diagnosing parameters of the hot and dense plasma state that receive widespread attention. But the probe light wavelength for Thomson scattering is more limited to the visible or ultraviolet light, so the electron density that is copable to be diagnosed is much lower than the critical density of the driving laser. In comparison, soft X-ray laser as a probe is hopeful for diagnosing higher density of plasma. The experimental attempt of soft X-ray laser Thomson scattering has been carried out using Ne-like Ge soft X-ray laser generated on the SG-II high-power laser device. According to the scattering case, incoherent scattering and coherent scattering experiments were carried out, but it is unable to obtain the significant scattering spectrum. Theoretical analysis shows that the main reason may be the focusing power density of Ne-like Ge soft X-ray laser being not enough, in the experiments. By optimizing the experimental conditions, it is expected to obtain coherent Thomson scattering in the future.
Keywords： plasma diagnostic Soft x-ray lasers Thomson scattering