Journal ArticleDOI
Stimulated scattering of light by ion modes in a homogeneous plasma: Space-time evolution
Bruce I. Cohen,Claire E. Max +1 more
TLDR
In this article, a generalized Green's function is found that describes the impulse response for stimulated scattering by electron and ion modes in a coherent electromagnetic plane wave propagating in a uniform plasma.Abstract:
Stimulated Brillouin scattering, filamentation, and induced Thomson scattering are studied for a coherent electromagnetic plane wave propagating in a uniform plasma. A generalized Green’s function is found that describes the impulse response for stimulated scattering by electron and ion modes. Explicit asymptotic Green’s functions are calculated for those parametric instabilities involving ion modes or quasi‐modes. Special attention is given to whether the instabilities are convective or absolute. For a traveling wave pump in a uniform plasma, Brillouin and induced Thomson backscatter can be absolute, but sidescatter is convective; filamentation of traveling waves is always convective. Spatial growth rates are calculated for convectively unstable modes. Finally, the competition of filamentation and stimulated Brillouin scattering is considered for parameters typical of real laser‐fusion experiments.read more
Citations
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Smilei : A collaborative, open-source, multi-purpose particle-in-cell code for plasma simulation
Julien Derouillat,Arnaud Beck,Frederic Perez,Tommaso Vinci,M. Chiaramello,Anna Grassi,Anna Grassi,M. Flé,G. Bouchard,I. Plotnikov,Nicolas Aunai,J. Dargent,J. Dargent,Caterina Riconda,Mickael Grech +14 more
TL;DR: The Vlasov–Maxwell system describing the self-consistent evolution of a collisionless plasma is solved using the Particle-In-Cell (PIC) method, and a hybrid MPI-OpenMP strategy, based on a patch-based super-decomposition, allows for efficient cache-use, dynamic load balancing and high-performance on massively parallel super-computers.
Journal ArticleDOI
The physics of the nonlinear optics of plasmas at relativistic intensities for short-pulse lasers
Abstract: The nonlinear optics of plasmas at relativistic intensities are analyzed using only the physically intuitive processes of longitudinal bunching of laser energy, transverse focusing of laser energy, and photon acceleration, together with the assumption of conservation of photons, i.e., the classical action. All that is required are the well-known formula for the phase and group velocity of light in plasma, and the effects of the ponderomotive force on the dielectric function. This formalism is useful when the dielectric function of the plasma is almost constant in the frame of the light wave. This is the case for Raman forward scattering (RFS), envelope self-modulation (SM), relativistic self-focusing (SF), and relativistic self-phase modulation (SPM). In the past, the growth rates for RFS and SPM have been derived in terms of wave-wave interactions. Here we rederive all of the aforementioned processes in terms of longitudinal bunching, transverse focusing, and photon acceleration. As a result, the physical mechanisms behind each are made clear and the relationship between RFS and envelope SM is made explicitly clear. This allows a single differential equation to be obtained which couples RFS and SM, so that the relative importance between each process can now be predicted for given experimental conditions.
Journal ArticleDOI
Theory and three‐dimensional simulation of light filamentation in laser‐produced plasma
TL;DR: In this paper, the effects of nonlocal electron transport and kinetic ion damping of the acoustic waves are modeled in a three-dimensional fluid model, and a simple criterion is obtained analytically and supported by simulations for stabilization of filamentation by laser beam-smoothing techniques such as induced spatial incoherence and random phase plates.
Journal ArticleDOI
Effects of ion trapping on crossed-laser-beam stimulated Brillouin scattering
E. A. Williams,Bruce I. Cohen,Laurent Divol,M. R. Dorr,Jeffrey Hittinger,Denise Hinkel,A. B. Langdon,R. K. Kirkwood,Dustin Froula,Siegfried Glenzer +9 more
TL;DR: An analysis of the effects of ion trapping on ion acoustic waves excited by the stimulated Brillouin scattering of crossing intense laser beams is presented in this paper, along with reasonably successful comparisons of the theory to results from particle simulations and laboratory experiments.
Journal ArticleDOI
Resonantly excited nonlinear ion waves
TL;DR: In this paper, a Boltzmann fluid model is used for the electrons and a particle-in-cell representation for the ions to simulate ion wave phenomena efficiently, while retaining a fully kinetic representation of the ions, and a new dispersion relation is derived describing the parametric instability of ion waves, evidence for which is observed in their simulations.
References
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Journal ArticleDOI
Parametric Instabilities of Electromagnetic Waves in Plasmas
TL;DR: In this article, a simple formalism for the parametric decay of an intense, coherent electromagnetic wave into an electrostatic wave and scattered electromagnetic waves in a homogeneous plasma is developed.
Journal ArticleDOI
Theory of stimulated scattering processes in laser‐irradiated plasmas
TL;DR: In this paper, the linear and nonlinear behavior of the one-dimensional Brillouin and Raman scattering instabilities is analyzed for the problems of an infinite homogeneous plasma and of a finite inhomogeneous plasma.
Journal ArticleDOI
Self-Modulation and Self-Focusing of Electromagnetic Waves in Plasmas
TL;DR: In this article, the nonlinear frequency shift of a strong electromagnetic wave in a plasma, due to weak relativistic effects and the $\stackrel{\ensuremath{\rightarrow}}{\mathrm{v}}\ifmmode\times\else\texttimes\fi{}\stackrel{ensureMath{\right arrow}}{B}}$ force, can cause modulation and self-focusing instabilities.