激光等离子体中Thomson散射光谱的拟合

依据无碰撞、无磁场、麦克斯韦速度分布等离子体模型下的Thomson散射理论编写了一维Thomson散射光谱拟合程序，并考虑了等离子体中的热流引起的电子相对漂移.研究了诊断系统的谱分辨率、收集立体角、Thomson散射参数α、等离子体参数梯度和电子的相对漂移速度对Thomson光谱拟合的影响.等离子体不均匀性和有限收集立体角对参数诊断影响很小，因此可以用无梯度无收集立体角的拟合程序简化处理；实验中为了提高信号的信噪比可以适当增加收集立体角；α较小时对拟合影响很大，实验中可以通过选取散射角提高α值和精确监测等离子体密度来减小它的影响. 关键词： Thomson散射 激光等离子体 电子相对漂移

Precisely fitting Thomson scattering spectrum in laser-produced plasmas

Based on the collisionless,Maxewellian Thomson theory,a program is developed for carefully analyzing the influence of experimental set-up and plasma gradients and electron drifts on Thomson scattering spectrum. Calculations show that spectra resolution,collection angle,drift velocity and plasma gradient only have minor effects on diagnostics,so we can conveniently ignore these in fitting the spectrum. An important result is that signal-to-noise ratio can be enhanced by increasing the collection angle of the experimental system. The uncertainty of the scattering parameter can strongly affect the inferred plasma parameters when it is less than 3. This problem could be solved by choosing a smaller scattering angle or by accurately measuring the plasmas density.