Enhanced Raman scattering of a laser beam in an unmagnetized collisional plasma

Summary form only given, as follows. The nonlinear three-wave interaction, as a physical concept in its variety of appearances has found its applications in hydrodynamics, nonlinear optics and plasma physics. There has been of considerable interest in the interactions of intense laser beams with plasmas. In this paper we have studied the nonlinear interaction of a rippled laser beam with an electron plasma wave leading to enhanced Raman scattering in a collisional unmagnetized plasma. The coupling between the main beam, ripple and plasma wave is strong. The excited plasma wave further interacts with rippled laser beam giving rise to enhanced Raman scattering. The role of collisional parameter S is highlighted. An expression for the scattered power is set up and solved numerically using Runge-Kutta method. The effects of the intensity of main beam and phase angle between ripple and the main beam on the normalized scattered power are also discussed. It is observed that the normalized scattered power is suppressed with increase in intensity of the main beam.