Anomalous Stimulated Raman Scattering and Electron Acoustic Waves in Laser-Produced Plasmas: A Linear Model

LLE Review, Volume 92 181 Stimulated Raman scattering (SRS), an instability in which light is scattered by and amplifies electron plasma waves, has long been a concern in laser-fusion research because of its potential to reduce absorption and implosion efficiency. This concern is enhanced by the unsatisfactory state of the theory, particularly in accounting for the prevalence of anomalous SRS—scattering from plasma waves that according to conventional theory should be very heavily Landau damped.1–5 Furthermore, scattering from waves satisfying the electron-acoustic (EA) dispersion relation (see below), which according to conventional theory should also be very heavily damped, has recently been identified.2,4 These observations imply that Landau damping in laser-produced plasmas is often lower by an order of magnitude than would be predicted by the conventional linear theory of waves in a Maxwellian plasma.5