Stimulated Raman scattering of a laser in a plasma with clusters

The presence of sub-micron size clusters in a gas jet plasma considerably modifies the dispersion relations for electromagnetic and Langmuir waves. A high intensity laser propagating through such a plasma undergoes stimulated Raman scattering (SRS). The free electrons inside the clusters play a significant role in the nonlinear coupling. The growth rate of SRS increases with the increase in cluster density in a low-density gas jet. Damping of the laser in cluster plasma introduces an intensity threshold that increases rather rapidly with decrease in pulse duration