Three dimensional analysis of nonlinear plasma oscillation
Three dimensional analysis of nonlinear plasma oscillation
复制标题
非线性等离子体振荡的三维分析
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
G. Miano
中科院分区：
文献类型：
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作者：
G. Miano
在低密度等离子体中，两个外部共线电磁波的频率差近似等于等离子体频率-等离子体拍波（PBW）共振机制，可以产生等离子体的大幅度振荡。等离子体的振荡是由两个施加的电磁波的振动所产生的有源动力驱动的。本文研究了具有任意横剖面的两种泵浦电磁波。用三维弱相对论流体方程描述等离子体。采用欧拉描述法、平均法和多时间尺度法研究了等离子体的非线性振荡动力学。与线性理论不同，等离子体振荡的纵向和横向电场分量之间存在强的交叉场耦合，导致两个分量之间的非线性相变和能量传递。与一维非线性理论不同，非线性频移是由相对论效应以及三维等离子体振荡产生的对流效应和电磁场引起的。具有任意横截面的束状相对论电子束-等离子体尾迹场（PWF）或具有任意横截面的高功率单频短电磁脉冲-电磁等离子体尾迹场（EPWF）所产生的等离子体大振幅振荡动力学可以用本理论来描述。
In an underdense plasma a large-amplitude plasma oscillation may be produced by the beating of two external and colinear electromagnetic waves with a frequency difference approximately equal to the plasma frequency - plasma beat wave (PBW) resonant mechanism. The plasma oscillations are driven by the ponderomotive force arising from the beating of the two imposed electromagnetic waves. In this paper two pump electromagnetic waves with arbitrary transverse profiles have been considered. The plasma is described by using the three dimensional weakly relativistic fluid equations. The nonlinear plasma oscillation dynamics is studied by using the eulerian description, the averaging and the multiple time scale methods. Unlike the linear theory a strong cross field coupling between longitudinal and transverse electric field components of the plasma oscillation comes out, resulting in a nonlinear phase change and energy transfer between the two components. Unlike the one-dimensional nonlinear theory, the nonlinear frequency shift is caused by relativistic effects as well as by convective effects and electromagnetic field generated from the three dimensional plasma oscillation. The large amplitude plasma oscillation dynamics produced by a bunched relativistic electron beam with arbitrary transverse profile - plasma wake field (PWF) - or by a high power single frequency short electromagnetic pulse with arbitrary transverse profile - electromagnetic plasma wake field (EPWF) - may be described by means of the present theory.