多光子非线性Compton散射对激光等离子体中强朗缪尔湍动谱的影响

Influence of Strong Langmuir Turbulence in Laser-plasma by Multi-photon Nonlinear Compton Scattering

基于电子与多光子集团非线性Compton散射模型,研究了多光子非线性Compton散射对激光等离子体中强缪尔湍动谱的影响,提出了将入射光和散射光作为形成强缪尔湍动的新机制,给出了横等离激元、强朗缪尔激元和离声激元之间相互作用满足的修正方程,并进行了数值模拟.结果表明:Compton散射使横等离激元和朗缪尔激元间的碰撞频率大大增加,随着时间的演化,横等离激元和朗缪尔激元的能量由小波数区向大波数区的转移比散射前要快得多,同时产生剧烈的坍塌.坍塌后期,等离激元的强非线性作用激发出高次共振谐波,使能量从一个谐波转移到另一个谐波,形成无限高次谐波,引起波的破碎,出现由调制不稳定性控制的强朗缪尔湍动、较强的激光成丝和能量均分现象.研究结果为进一步研究强朗缪尔湍动的加速机制、反常碰撞、激光加热实验及快点火实验提供了理论支持.

According to the model of multi-photon nonlinear Compton scattering,the influence of the multi-photon nonlinear Compton scattering on the strong Langmuir turbulence spectra in the laser-plasma is studied.A new mechanism of the strong Langmuir turbulence formed by the incident light and scattered optical is given.The revised equation met by the mutual action on the transverse plasma wave,the strong Langmuir turbulence wave and ion acoustic wave and its results of the numerical number modulation are also given.The results show that because the collision frequency between the transverse plasma wave and strong Langmuir turbulence wave is greatly increased by Compton scattering,along the time evolution,the transformation of the energy from the small-k region to the large-k region between the transverse plasma wave and Langmuir wave is faster than that before Compton scattering,and the strenuous collapsing is taken place at the same time.During the anaphase of collapse,the nonlinear effect of the laser-plasma excites out the high degree resonance waves.The energy is diverted from one of the resonance wave to another,and the infinite high degrees resonance wave is formed.The phenomenon on breakage of the wave,the strong Langmuir turbulence controlled by the modulation instability,the stronger laser filamentation and energy egalitarian are taken place.The research results will provide a theoretic support for the further study on the increasing speed mechanism of the strong Langmuir turbulence,abnormal collision and laser heating experimentation and fast igniting experimentation.