Raman scattering in inhomogeneous laser-produced plasma

Abstract
A model of Raman scattering in inhomogeneous laser‐produced plasma is described, which invokes enhanced Thomson scattering. The enhancement is caused by pulses of hot electrons arising from laser–plasma interactions at the critical or quarter‐critical surfaces. A simple model predicts the locations of two enhanced frequency bands, one between ω0 and ω0/2, and the other between 2ω0 and ω0. The model is shown to fit the results of eight experiments, including a new experiment using the six‐beam Omega laser facility [Phys. Rev. Lett. 4 8, 1179 (1982); Phys. Fluids 2 7, 2181 (1984)], converted to 351 nm. In this latter experiment, simultaneous measurement of the upscattered and downscattered bands is carried out, and good agreement is found with the enhanced Thomson model.