Multimode excitation and modulational instability of beam plasma system with Tsallis-distributed electrons

In the present investigation, authors have studied the linear mode structure of electron-acoustic waves, their modulational instability and rogue wave profiles in four-component plasma system consisting of stationary ions, cold electron fluid, Tsallis-distributed hot electrons and an electron beam. By applying standard perturbation method to the fluid equations, the dispersion relation is obtained that depends on various parameters such as beam density, beam velocity, beam temperature and non-extensivity q. Based on the phase velocities, two electron-acoustic (EA) modes known as slow and fast, have been extracted as real modes for which a detailed analysis is presented. Further, the basic set of equations is reduced to nonlinear Schrodinger equation (NLSE), where the nonlinearity and dispersion coefficients compete and significantly affect the stability characteristics of EA waves. For both the modes, a comprehensive study of modulational instability and rogue wave profile has been carried out by taking into consideration the effect of non-extensivity and beam velocity. The obtained results have been compared with other research works. The present investigation may be relevant to the observation from Viking satellite in the day-side auroral zone.