Spatially autoresonant stimulated Raman scattering in inhomogeneous plasmas in the kinetic regime
- Centre de Physique Theorique, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France)
- CEA, DAM, DIF, F-91297 Arpajon (France)
- Department of Physics, Theoretical Physics Institute, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada)
The impact of spatial autoresonance on backward stimulated Raman scattering in inhomogeneous plasmas is investigated in the regime where the dominant nonlinear frequency shift of the Langmuir wave is due to kinetic effects. By numerically solving the coupled mode equations, the spatial growth of the Langmuir wave is observed to self-adjust so as to cancel the detuning from resonance due to inhomogeneity, giving rise to phase-locked solutions to the electron plasma wave equation. For a single resonant point in a linear density profile, the envelope of the electron plasma wave is characterized by a growth that begins at the resonant point and is proportional to the square of distance propagated. In the more physical case where the scattered light is seeded with a broadband noise, autoresonance may lead to a reflectivity well above the level predicted by the usual Rosenbluth gain factor [M. N. Rosenbluth, Phys. Rev. Lett. 29, 565 (1972)].
- OSTI ID:
- 21532085
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 12 Vol. 17; ISSN PHPAEN; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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