Stimulated Raman scattering in self-focused light filaments in laser-produced plasmas

Abstract
The stimulated Raman scattering instability is treated for laser light propagating through a plasma in a self‐focused filament. It is shown that self‐focusing of hot spots in the incident laser beam can greatly enhance the growth rate of the instability. This result may help to explain experimental observations of Raman scattering at nominal incident intensities well below the theoretical threshold, and may also account for an anomalous spectral structure that has been observed at low intensities.