Stimulated Raman scattering of high power beam in thermal quantum plasma

Abstract

Stimulated Raman Scattering (SRS) of high power beam in thermal quantum plasma (TQP) is investigated in present communication. There is an interaction of pump beam with electron plasma wave (EPW), which results in generation of back-scattered beam. Due to intense laser beam, oscillatory velocity associated with electrons becomes equivalent to velocity of light on account of intense laser beam. This results in modification of background density profile of plasma in a direction normal to axis of pump beam. There is increase in effective mass of electrons on account of relativistic nonlinearity, which in turn affects the incident beam, EPW and scattered beam. 2nd order differential equations for the beam widths of input beam, EPW and scattered beam and also expression for back-reflectivity have been set up by using WKB and paraxial approximations. Effects of variation in laser parameters and plasma parameters on the beam widths of various beams involved and SRS back-reflectivity are analyzed. Observations made from the analysis show that SRS back reflectivity is greatly affected by self-focusing.