Combined effects of density ripples and transverse magnetic field on the suppression of stimulated Raman scattering of X- mode laser in a plasma

The present study shows that stimulated Raman Scattering of X-mode lasers may be suppressed significantly due to the presence of density ripples and transverse magnetic field in plasma. A laser propagating in magnetized plasma excites a primary upper hybrid wave and a sideband electromagnetic wave. Primary upper hybrid wave couples with density ripples and excites a secondary upper hybrid of same frequency but of longer wave number. Secondary wave is strongly Landau damped and diverts the energy available in feedback mechanism of Raman process. As a consequence, the growth rate of SRS reduces significantly. The growth rate of Raman process also decreases with applied magnetic field. The growth of Raman process is reduced ∼ 40% when the ripple wave number is twice the propagation constant of pump laser (intensity 1015 W/ cm2 at 1μm wavelength) in a 10% critical density plasma having electron temperature 1 keV.