Saturation process induced by vortex-merging in numerical Vlasov-Maxwell experiments of stimulated Raman backscattering

M. Albrecht-Marc (1) , A. Ghizzo (1) , T. W Johnston (2) , T. Reveille (1) , D. del Sarto (1) , Pierre Bertrand (1)

1 LPMIA - Laboratoire de physique des milieux ionisés et applications
2 INRS - Institut National de la Recherche Scientifique [Québec]

The influence of low-frequency nonlinear Bernstein-Greene-Kruskal (BGK)-type waves induced by trapped electrons in backward stimulated Raman scattering is investigated in optical mixing. Semi-Lagrangian Vlasov-Maxwell simulations show two nonlinear behaviors. First, there is a Morales-O’Neil plasma wave frequency downshift retuned by a small wavenumber shift which maintains the Stimulated Raman Scattering (SRS) resonance. The saturation of Raman backscattering begins with phase space vortex merging followed by a transition to lower wavenumbers following the (nonlinear) dispersion relation, resembling weak turbulence.

Domaines: Physique des plasmas [physics.plasm-ph]; Physique de l'espace [physics.space-ph]; Dynamique des Fluides [physics.flu-dyn]; Physique mathématique [math-ph]; Physique des Hautes Energies - Théorie [hep-th]; Dynamique Chaotique [nlin.CD]; Calcul parallèle, distribué et partagé [cs.DC]

M. Albrecht-Marc, A. Ghizzo, T. W Johnston, T. Reveille, D. del Sarto, et al.. Saturation process induced by vortex-merging in numerical Vlasov-Maxwell experiments of stimulated Raman backscattering. Physics of Plasmas, 2007, 14 (7), pp.072704. ⟨10.1063/1.2749715⟩. ⟨hal-01804605⟩