Excitation of Electromagnetic Wake Fields by one-dimensional Electron Bunch in Plasma in the Presence of Circularly Polarized Intense Electromagnetic Wave

Abstract

The excitation of electromagnetic (EM) wake waves in electron plasma by an one-dimensional bunch of charged particles has been considered in the presence of intense monochromatic circularly polarized electromagnetic (CPEM) pump wave. In the zero state (in the absence of bunch) the interaction of the pump wave with plasma is described by means of Maxwell equations and relativistic nonlinear hydrodynamic equations of cold plasma. The excitation of linear waves by one-dimensional bunch is considered on this background. It is shown that there are three types of solutions of linear equations obtained for induced waves corresponding to three ranges of parameter values of the pump wave, bunch and plasma. In the first range of parameter values the amplitude of transverse components of induced waves is shown to grow as the bunch energy and after some value of the relativistic factor of the bunch to be almost independent of the energy and increase proportional to the intensity and frequency of the pump wave. The dependence of longitudinal component of induced waves on the relativistic factor of the bunch is weak. Its amplitude and wavelength grow as the intensity of pump wave. The second range of parameters is a resonance one. The amplitude of the wave excited by the bunch is a linear function of the distance to the bunch. In the third range of parameter values the longitudinal component of induced fields are localized near the bunch boundaries and are exponentially decreased with the increase in distance from these boundaries. The amplitudes of transverse components of induced waves reach a constant value with the distance from the bunch boundaries.