Steady copropagation mode of laser pulse and plasma wave

Stimulated Raman scattering is investigated using a nonperturbative method. The existence of steady copropagation modes of laser field and plasma wave is discussed. The plasma wave strength is analyzed through its relation with the total energy of the laser-plasma system. It is found that at a sufficiently high laser intensity there exist stable copropagating modes with non-zero-strength plasma waves. The strength of plasma wave in a stable steady copropagation mode is found to have an exact expression in terms of the frequency, the wave vector of the plasma wave and the laser intensity.