This article discusses the existence of solitary electromagnetic waves trapped in a self-generated Langmuir wave and embedded in an infinitely long circularly polarized electromagnetic wave propagating through a plasma. From the mathematical point of view they are exact solutions of the 1-dimensional relativistic cold fluid plasma model with nonvanishing boundary conditions. Under the assumption of traveling wave solutions with velocity $V$ and vector potential frequency $ω$, the fluid model is reduced to a Hamiltonian system. The solitary waves are homoclinic (grey solitons) or heteroclinic (dark solitons) orbits to fixed points. By using a dynamical systems description of the Hamiltonian system and a spectral method, we identify a great variety of solitary waves, including asymmetric ones, discuss their disappearance for certain parameter values, and classify them according to: (i) grey or dark character, (ii) the number of humps of the vector potential envelope and (iii) their symmetries. The solutions come in continuous families in the parametric $V-ω$ plane and extend up to velocities that approach the speed of light. The stability of certain types of grey solitary waves is investigated with the aid of particle-in-cell simulations that demonstrate their propagation for a few tens of the inverse of the plasma frequency.
Reflection of a dust acoustic solitary wave in a dusty plasma
我们报告的第一个实验观测的反射尘埃声孤波从一个潜在的障碍在尘埃等离子体介质。实验是在一个倒置的$Π$形状的尘埃等离子体实验（DPEx）设备中进行的，在直流辉光放电等离子体环境中。尘埃声孤波是通过叠加在放电电压上的短负高斯脉冲调制等离子体激发的。孤立波结构被认为是朝着一个潜在的障碍，产生的鞘周围偏置的电线，并返回后反射的障碍。记录了孤子的振幅、宽度和速度随时间的变化。对不同势垒强度和不同初始孤立波振幅的情况重复实验。发现孤立波最接近势垒中心的距离随势垒强度的增大而增大，随初始波幅的减小而减小。发射探针用于测量鞘层电位及其厚度，通过测量连接到偏置线的电阻范围内的轴向方向上的等离子体电位分布。修正的Korteweg de Vries方程的推导和数值求解定性地了解实验结果。
