Relativistic and ponderomotive self‐focusing of a laser beam in a radially inhomogeneous plasma. II. Beyond the paraxial approximation
Relativistic and ponderomotive self‐focusing of a laser beam in a radially inhomogeneous plasma. II. Beyond the paraxial approximation
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DOI：
10.1063/1.870756
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发表时间：
1994-04
影响因子：
2.2
通讯作者：
G. Bonnaud;H. Brandi;C. Manus;G. Mainfray;T. Lehner
中科院分区：
文献类型：
--
作者：
G. Bonnaud;H. Brandi;C. Manus;G. Mainfray;T. Lehner
通过二维模拟分析了高强度电磁波在等离子体中的传播，电磁波引起相对论质量增加和电子的有质动力排出。波的时间/空间演化由轴对称标量波方程建模，其中等离子体频率是波能量的瞬时和局部函数;假设入射辐照度在时间上是恒定的。首先讨论了相对论聚焦的特点。有质动力效应通过驱逐等离子体电子、在光束边缘产生密度隆起和尖锐的密度梯度来强制聚焦过程;非线性聚焦更快且更强，证实了第I部分[Phys. Fluids B 5，3539（1993）]中提出的傍轴/高斯光束核心分析。与第一部分相反，光在锐边密度通道中被引导。径向密度不均匀性的影响，然后检查通过使用凸（盆地形状）和凹（凸块形状）。
The propagation in a plasma of a high‐intensity electromagnetic wave inducing both relativistic mass increase and ponderomotive expulsion of electrons is analyzed via two‐dimensional simulations. The time/space evolution of the wave is modeled by an axisymmetric scalar wave equation in which the plasma frequency is an instantaneous and local function of the wave energy; the incident irradiance is assumed to be constant in time. The specific features of relativistic focusing are first discussed. The ponderomotive effect enforces the focusing process by expelling the plasma electrons, creating density bumps and sharp density gradient on the edge of the light beam; the nonlinear focusing is faster and stronger confirming the paraxial/Gaussian beam core analysis presented in Part I [Phys. Fluids B 5, 3539 (1993)]. In contrast to Part I, the light is guided in a sharp‐edged density channel. The influence of the radial density inhomogeneity is then examined by using both convex (basin shape) and concave (bump s...