Stimulated Raman scattering in a plasma channel

An intense laser beam propagating in a low-density plasma channel undergoes stimulated Raman forward scattering, producing a plasma wave and two electromagnetic sideband waves. The electromagnetic waves are localized within a width ∼(ca/ωp0)1/2, where a is the radius of the channel, ωp0 is the plasma frequency on the axis of the channel, and c is the velocity of light, whereas the localization of the plasma wave is dependent on the growth rate of the Raman process. The localization effects reduce the region of interaction and the growth rate. At moderate intensities the growth rate scales as 2/3 power of intensity, however, at higher intensities it varies less rapidly.