Solitary electromagnetic pulses in a retarding system with an electron-ion beam

Abstract

The propagation of a combined electron-ion beam in a retarding plasma-filled system under the conditions of cyclotron (abnormal Doppler) resonance of electrons with the wave is studied. We show the possibility of existence of resonant electromagnetic solitons, which propagate along the beam. The nonlinear dispersion law and group velocity of the soliton are determined. Special attention is paid to the case in which effects associated with the longitudinal polarization field, which appears during charge separation in the electromagnetic-pulse field, are important. By numerical integration we have found solutions of the solitary-wave type, which exist for the discrete spectrum of system parameters. For the limiting case of rarefied plasma, when the discrete spectrum becomes continuous, the solution is found in the adiabatic approximation.