Compton散射下等离子体交叉相位调制不稳定性增益谱  

Gain spectrum of the cross-pulse modulation instability in plasma under Compton scattering

作　　者：禹定臣[1] 郝晓飞[1] 郝东山[1] 

机构地区：[1]黄淮学院信息工程学院,驻马店463000

出　　处：《原子与分子物理学报》2013年第1期167-172,共6页Journal of Atomic and Molecular Physics

基　　金：河南省基础与前沿技术研究资助项目(092300410227)

摘　　要：应用多光子非线性Compton散射模型和非线性Schrodinge方程,将入射光和Compton散射光作为形成等离子体交叉相位调制不稳定性的新机制,给出了高阶色散和高阶非线性下等离子体交叉相位调制不稳定性增益谱表达式,并进行了数值模拟.结果表明:与Compton散射前相比,Comnpton散射下的四阶色散使等负色散区的交叉相位调制不稳定性的两个频谱宽度比正色散区的宽,增益谱第二谱区及其峰值更接近零点,即使小功率光波,高频散射光的高阶色散和高阶非线性对交叉相位调制不稳定性的影响依然不可忽略.正五阶非线性使交叉相位调制不稳定性加强,第二谱区增益谱宽和峰值比第一谱区增大得更为明显;负五阶非线性对交叉相位调制不稳定性起抑制作用,五阶非线性系数绝对值越大,抑制作用越明显.散射使等离子体损耗对交叉相位调制不稳定性的影响减弱,随传输距离增加,增益谱宽缓慢减小.这主要是由于散射产生的非线性有效地补偿因传输距离增加而减小非线性的缘故.Using the model of the multi-photon nonlinear Compton scattering and Schr^Sdinge＇s equation, a new mechanism of the cross-pulse modulation instability（CPMI）in the plasma formed by the incident light and scattered light is given,the expression formulas of the CPMI gain under the high-order disper- sion and high-order nonlinearity in the plasma are given and these expression formulas have been simula- ted using numbers. The results show that after considering Compton scattering,the widths of the two frequency spectrums in the negative dispersion regime are wider than those in the positive dispersion re- gime. The second spectrum regime of the gain spectrum and its peak value are closer to naught point, e- ven for the small power light wave. The influences of the CPMI induced by the high-order dispersion and high-order nonlinearity of the high frequency scattered optical stilly can not be ignored. The positive quintic nonlinearity results in the increase at CPMI,the increases of the width and peak value of the gain spectrum in the second spectrum regime are clearer than those in the first spectrum regime. The de- pressant effect to the CPMI is induced by the negative quintic nonlinearity. The bigger the absolute val- ue of the quintic nonlinear coefficient, the clearer the depressant effect. The influences on plasma loss induced by the scattering to the CPMI decrease and gain spectrum widths decrease slowly with the in- creasing propagation distances. The key cause is that the nonlinear decrease with the increase of propa-gation distance is compensated by the nonlinearity induced by the scattering.

关 键 词：非线性光学 交叉相位调制不稳定性 四阶色散 五阶非线性 COMPTON散射 增益谱 

分 类 号：O431[机械工程—光学工程]