Slow electrostatic fluctuations generated by beam-plasma interaction
Slow electrostatic fluctuations generated by beam-plasma interaction
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束-等离子体相互作用产生的缓慢静电波动
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
P. Veltri
中科院分区：
文献类型：
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作者：
K. Pommois;F. Valentini;O. Pezzi;P. Veltri
Vlasov-Poisson 方程的欧拉模拟已用于分析由于束-等离子体相互作用而引起的慢静电波动（相速度接近电子热速度）的激发及其在线性和非线性状态下的传播。 1968 年，奥尼尔和马尔姆伯格 [Phys. Fluids 11, 1754 (1968)]将这些波称为“光束模式”。本文对线性和非线性束流模式的分析结果进行了数值回顾，指出当电子束在麦克斯韦电子和静止质子的等离子体中发射时，这种初始平衡受到单色密度扰动的扰动，电场幅度随时间呈指数增长，然后经历非线性饱和，这与粒子捕获和相空间涡旋产生的动力学效应有关。此外，新的数值结果证明，当初始密度扰动以低幅度的形式设置时……
Eulerian simulations of the Vlasov-Poisson equations have been employed to analyze the excitation of slow electrostatic fluctuations (with phase speed close to the electron thermal speed), due to a beam-plasma interaction, and their propagation in linear and nonlinear regimes. In 1968, O'Neil and Malmberg [Phys. Fluids 11, 1754 (1968)] dubbed these waves “beam modes.” In the present paper, previous analytical results on the beam modes in both linear and nonlinear regimes have been revisited numerically, pointing out that, when an electron beam is launched in a plasma of Maxwellian electrons and motionless protons and this initial equilibrium is perturbed by a monochromatic density disturbance, the electric field amplitude grows exponentially in time and then undergoes nonlinear saturation, associated with the kinetic effects of particle trapping and phase space vortex generation. Moreover, new numerical results give evidence that, when the initial density perturbation is setup in the form of a low amplitu...