On the Dynamics of Langmuir Wave Soliton

Various descriptions for the one-dimensional Langmuir wave soliton are classified according to the relations among various smallness parameters. Four different regimes are found to emerge depending on the relative importance of various forces acting on the electrons and are graphically represented in the parameter space. When the field energy becomes as large as the electron kinetic energy, second harmonic generation and local charge separation (in slow time scale) are found to occur, but their effect on the description of the Langmuir wave soliton is found insignificant. Dynamic behavior of the Langmuir wave soliton is discussed in terms of the trajectory in the parameter space and is compared with recent experimental and numerical analyses.