超强激光参数对等离子体折射系数的影响分析

分析了超强激光与等离子体相互作用的“准静态”冷等离子体模型,求出了等离子体相对于矩形和非矩形脉冲激光的折射系数;讨论了激光参数对等离子体折射系数的影响,结果发现：1）当激光强度归一化矢势的大小大于1.4时,在同一激光强度下,矩形激光对应的静电势大于非矩形激光对应的静电势,激光强度越小,两者的差异越小;2）在同一激光强度下,矩形脉冲激光引起的折射系数远较非矩形激光脉冲引起的折射系数大;3）不管是哪种脉冲激光,只要激光强度增加,折射系数都增加,但矩形脉冲激光更易使折射系数达到1;4）在激光强度一定时,随着脉冲激光波长的增加,折射系数都按一定的指数规律减少,非矩形脉冲激光的减少幅度大于矩形脉冲激光减少的幅度;5）当波长趋于零时,折射系数都趋于1,这是由于脉冲激光的频率增高,等离子体中产生了非常强的 “透镜”效应所至.

The Influence Analyses of Superstrong Laser Parameter to Refraction Coefficient of Plasma

The “near static state” cold plasma model of the interaction between the super-stength laser and the plasma was analysed.The refraction coefficient of plasma relativing to rectangle-pulse laser and un-rectangle-pulse laser were worked out.The influence of laser parameter to the refraction coefficient of plasmawasdiscussed.Theresultsarefounded:1)Whenthesizeofunitaryvectorpotentialislargerthan1.4,under the same laser strength,the electrostatic potential of rectangle laser is larger than that of the un-rectangle laser.And the less of laser strength is,the less is the discrepancy between the two;2)Under the same laser strength, the refraction coefficient aroused by rectangle-pulse laser is much bigger than that aroused by un-rectangle-pulse laser;3)No matter which kind the pulse laser is,so long as the laser strength increases,the refraction coefficient will increase too.But only the rectangle-pulse laser is the most easy to make the refraction coefficient reach 1;4)When the laser strength is certain,with the inc