相对论效应对大振幅电子等离子体振荡破裂影响的数值模拟  

Vlasov simulation of the relativistic effect on the breaking of large amplitude plasma waves

作　　者：徐慧[1] 盛政明[1] 张杰[1] 

机构地区：[1]中国科学院物理研究所光物理实验室,北京100080

出　　处：《物理学报》2007年第2期968-976,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10335020;10476033);国家杰出青年基金(批准号:10425416);国家高技术研究计划(863)资助的课题~~

摘　　要：通过数值求解符拉索夫方程和泊松方程,研究了相对论效应和温度效应对等离子体振荡破裂的影响.不考虑相对论效应情况下,初始扰动幅度较小时,不会发生等离子体振荡破裂,系统具有时间周期性.此时电子温度的增加,会使得等离子体振荡最大幅度减小.考虑相对论效应时,即使初始的等离子体电子密度扰动幅度不大,随着时间演化,相对论效应也能导致等离子体振荡破裂,而且初始电子密度扰动越小,产生等离子体振荡破裂所需时间越长.在初始电子密度扰动较大时,无论考虑和不考虑相对论效应都会出现波破裂,但两者的结果有很大不同.此外温度效应会降低能发生等离子体波破裂的阈值;等离子体波的相速度越大,能产生的波破裂现象也越明显.The influence of relativistic and thermal effects on plasma wave breaking has been studied by solving the coupled Vlasov- Poission equations. When the relativistic effect is not considered, the wave breaking will not occur, provided the initial perturbation is less than certain value as predicted previously, and the largest amplitude of the plasma wave will decrease with the increase of the initial temperature. When the relativistic effect is considered, wave breaking always occurs during the time evolution, irrespective of the initial perturbation amplitude. Yet the smaller the initial perturbation amplitude is, the longer is the time for wave breaking to occur. With large initial perturbations, wave breaking can always occur with and without the relativistic effect. However, the results are significantly different in the two cases. The thermal effects of electrons decrease the threshold value of initial amplitude for wave breaking and large phase velocity makes the nonlinear phenomenon occur more easily.

关 键 词：等离子体振荡 相对论效应 振荡破裂 

分 类 号：O534.1[理学—等离子体物理]