Speaker
Didier Bénisti
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P5.2002.pdf
Recent advances in the modeling of stimulated Raman scattering
D. Bénisti
CEA, DAM, DIF 91297 Arpajon Cedex, France
In this talk, we first present a quick overview of the recent theoretical results obtained, both,
in nonlinear wave-particle interaction and in the use nonlocal variational principles to describe
wave propagation. As an application, we show how to solve theoretically for the nonlinear
growth and saturation of the cold-beam plasma instability, and we introduce a set of coupled
envelope equations that the model stimulated Raman scattering. These equations account for
nonlinear kinetic effects, plasma inhomogenity and non stationarity in a three-dimensional ge-
ometry, and interspeckle coupling. They proved to provide accurate results as regards Raman
reflectivity in the nonlinear kinetic regime, within computation times reduced by about five
orders of magnitude compared to a Particle-In-Cell code.
In spite of their accuracy and effectiveness, the envelope equations cannot be solved directly
in the hydrodynamical codes used for inertial confinement fusion. Consequently, one needs to
introduce simplified models, and such a model, that accounts for nonlinear kinetics effects, is
introduced. Comparaisons between the results obtained with this model and the complete set of
equations are given, and the interplay between both approaches is discussed.
