【作者】 王晶晶；

【导师】 易林；

【作者基本信息】 华中科技大学 ， 光学， 2011， 硕士

【摘要】 激光惯性约束核聚变是比较有前景的核聚变研究方向,此系统中考虑到激光在等离子体中的传输。等离子体作为一种非线性介质,当满足一定条件时激光能在其中产生空间光孤子。激光的吸收的问题是解决核聚变问题的关键之一,激光与等离子体发生相互作用过程中产生的超热电子预热点火靶使得压缩度下降影响对激光的吸收,因此有必要对电子等离子波电子密度进行研究对其进行改进。本文主要研究激光与等离子体的相互作用。首先介绍了用分离变量与级数方法求解非局域非线性等离子体介质中非线性薛定谔方程,并研究了光束在此过程中的传输特性。然后介绍了用自相似方法求解,在电子等离子体波中的电子密度变量决定的一般非线性方程,研究电子密度的演化过程。通过分析我们可以得到下面的一些结论:1.光束的初始光束宽度受背景势场中的m,n量子数影响。不同β和A决定不同的调制势的值能改变两列波峰的重合速度和光场强度波峰值。光束随着距离的增加,光束由两列演化成一列,可以将等离子体中光传输运用于光信息间的耦合,且调制亮、暗孤子其表现出不同的传输特性。2.激光与等离子体相互作用过程中产生的电子等离子体波,其电子密度强度分布是周期性变化的,它是由等离子体与激光的固定特性所决定的。电子密度强度最大值波峰个数及强度都受m的影响,且呈现出一定的变化规律。电子等离子波电子密度强度极大值波峰的个数,随着量子数n的改变发生了变化,且呈现出2n的变化规律,波峰峰值也随着n而发生变化。更多还原

【Abstract】 Laser driven inertial confinement fusion is the more promising direction of fusion research. The system is considering the transmission of laser in plasma medium. When achieving certain range of condition, plasma as a nonlinear medium, laser can form spatial optical solitons in it. The absorption of laser is one of the key issues to solve fusion problem, thermal electron produced in the process of laser-plasma interaction, preheats ignition target to decline compressed degrees so that affecting the absorption of laser. So It is necessary to make research on electron densities of the electron plasma wave.In this paper, we study the laser-plasma interaction. First, by using the methods of separation of variables and progression, we make solutions to the nonlinear Schr?dinger equation in the strongly nonlocal nonlinear plasma medium, and study the propagation properties of beams in this process. And then by using the methods of self-similar to solve the general nonlinear Schr?dinger equation decided by electron density variable of electron plasma wave, study the evolution process of electron densities. The principal achievements obtained are as the following:1. The initial beam width of the beam is being affected by the quantum number of m and n. The different value of the variable ofβand A, deciding different modulation potential value, can change the Coincidence rate of two peaks and the intensity peaks of optical field. With the distance increasing, the beams evolved from two into one, we can use the characteristics in the coupling between light informations. The modulation of bright soliton and dark soliton showed different propagation properties.2. The electron plasma wave excited in the process of laser-plasma interaction, its electron densities intensity distribution is periodic, and it is determined by the inherent characteristics of laser and plasma. The number and intensity of maximum peaks of electron plasma waves are both affected by m, and display certain change laws. With the changing of quantum number n, the numbers of tremum peaks of electron plasma waves is 2n,and peaks value of electron plasma waves also changes.更多还原