Ion acoustic nonlinearities in stimulated Brillouin scattering

Journal Article · Thu Mar 01 04:00:00 EST 1984 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.864652· OSTI ID:5144001

Heikkinen, J A; Karttunen, S J; Salomaa, R R.E.

Reduction of stimulated Brillouin scattering by the generation of higher ion wave harmonics is investigated. A theory model is derived which includes all harmonics. A simplified model based on the truncation to second harmonic ion waves reveals several interesting features. When damping and detuning are neglected the reflectivity is drastically reduced in a low-density plasma (n/sub e/<0.25n/sub c/r), but the solution turns phase unstable at low reflectivity levels. Finite damping of ion waves extends the range of validity of the model. Still nonlinear damping of the primary decay may considerably exceed the linear damping, rendering the generation of the second harmonic an important mechanism. A large detuning of the second harmonic is required before it can be considered decoupled. The strong interaction between the ion waves introduces a power shift which is able to dynamically reduce the Brillouin reflectivity. Undersone parameter conditions the reflectivity approaches an oscillatory steady state. The accuracy of the second harmonic model rapidly improves as damping and detuning of the ion waves increase, suggesting that harmonic generation is important in a medium-length (L/L/sub g/<10), slightly damped plasma.

• Research Organization: Technical Research Centre of Finland, Nuclear Engineering Laboratory, SF-00181 Helsinki 18, Finland
• OSTI ID: 5144001
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 27:3; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
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BRILLOUIN EFFECT
COHERENT SCATTERING
ELECTROMAGNETIC PULSES
ELECTROMAGNETIC RADIATION
HARMONICS
INHIBITION
INTERACTIONS
ION WAVES
LASER-PRODUCED PLASMA
MATHEMATICAL MODELS
NONLINEAR PROBLEMS
OSCILLATIONS
PLASMA
PLASMA WAVES
PULSES
RADIATIONS
SCATTERING