超强激光参数对等离子体折射系数的影响分析  

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

作　　者：张可言[1] 

机构地区：[1]涪陵师范学院物理系,重庆408003

出　　处：《光子学报》2005年第11期1620-1624,共5页Acta Photonica Sinica

基　　金：涪陵师范学院院级重点学科建设基金[批准号:2003148]资助

摘　　要：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 “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 plasma was discussed. The results are founded ： 1） When the size of unitary vector potential is larger than 1.4, 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 increasing of the laser wavelength,the refraction coefficient will decrease by index law; and the extend of decreasing of un-rectangle-pulse laser is larger than that of rectangle-pulse laser; 5）When the wavelength tends to zero, the refraction coefficient will tends to 1. Because with the frequency of pulse laser is going up,the very strong “Lens” effect will be produced in plasma.

关 键 词：激光参数 等离子体 折射系数 “透镜”效应 

分 类 号：O437[机械工程—光学工程]