Nonlinear Behavior of Stimulated Brillouin and Raman Scattering in Laser-Irradiated Plasmas

Forslund, D. W.; Kindel, J. M.; Lindman, E. L.

doi:10.1103/physrevlett.30.739

Cited by 192 publications

(59 citation statements)

References 16 publications

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“…In fact, filamentation is indeed such a process with a light wave going to a transverse electrostatic perturbation at rest and primarily forward scattered waves in the interior. Furthermore, news came to Princeton that while we were busy with parametric excitation of electrostatic waves, it was recognized by the Los Alamos group (Forslund et al 1973) that equally important processes are conversion of incident light wave into a plasma wave and a scattered light wave at the shifted sideband frequency (viz. SRS or socalled stimulated Raman scattering) or a three-wave process converting incident light wave into an ion acoustic wave and a scattered wave at shifted sideband frequency (SBS or stimulated Brillouin scattering).…”

Section: Stimulated Scattering: General Theory Of Parametric Instabilmentioning

confidence: 99%

“…The pump and scattered electromagnetic waves were described by the Maxwell equations in which additional currents due to the movement of electrostatic density fluctuations by the velocity of the pump wave generated the source sideband currents. It has been shown in references Forslund et al (1973) and Drake et al (1974) that the general dispersion relation for parametric instabilities in the presence of pump wave E ¼ E 0 cosðk 0 x À x 0 tÞ takes the form 1 v e ðk; xÞ …”

Section: Stimulated Scattering: General Theory Of Parametric Instabilmentioning

confidence: 99%

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Nonlinear laser–plasma interactions

Kaw

2017

Rev. Mod. Plasma Phys.

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Soon after lasers were invented, there was tremendous curiosity on the nonlinear phenomena which would result in their interaction with a fully ionized plasma. Apart from the basic interest, it was realized that it could be used for the achievement of nuclear fusion in the laboratory. This led us to a paper on the propagation of a laser beam into an inhomogeneous fusion plasma, where it was first demonstrated that light would go up to the critical layer (where the frequency matches the plasma frequency) and get reflected from there with a reflection coefficient of order unity. The reflection coefficient was determined by collisional effects. Since the wave was expected to slow down to near zero group speed at the reflection point, the dominant collision frequency determining the reflection coefficient was the collision frequency at the reflection point. It turned out that the absorption of light was rather small for fusion temperatures. This placed a premium on investigation of nonlinear phenomena which might contribute to the absorption and penetration of the light into high-density plasma. An early investigation showed that electron jitter with respect to ions would be responsible for the excitation of decay instabilities which convert light waves into electrostatic plasma waves and ion waves near the critical frequency. These electrostatic waves would then get absorbed into the plasma even in the collisionless case and lead to plasma heating which is nonlinear. Detailed estimates of this heating were made. Similar nonlinear processes which could lead to stimulated scattering of light in the underdense region ðx [ x p Þ were investigated together with a number of other workers. All these nonlinear processes need a critical threshold power for excitation. Another important process which was discovered around the same time had to do with filamentation and trapping of light when certain thresholds were exceeded. All of this work has been extensively verified in laser plasma experiments and have become the backbone of our present understanding of how lasers nonlinearly interact with fully ionized fusion plasmas. A review of this early work will be presented. We shall also present a review of our involvement in the recent work on nonlinearpenetration of light into overdense plasmas with gradual and sharp interfaces.

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Section: Stimulated Scattering: General Theory Of Parametric Instabilmentioning

confidence: 99%

Section: Stimulated Scattering: General Theory Of Parametric Instabilmentioning

confidence: 99%

Nonlinear laser–plasma interactions

Kaw

2017

Rev. Mod. Plasma Phys.

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“…In addition, we assume prescribed laser fields, neglecting throughout the entire interaction any changes to the laser envelopes due to linear effects such as diffraction or group-velocity dispersion, or any nonlinear back-action of the plasma on the lasers such as depletion, self-focusing, photon acceleration due to ionization or density variation, as well as Raman scattering, self-modulation, and other instabilities [35,36]. This model, although simplified, nevertheless reveals the essential features of autoresonance and its potential advantages for the PBWA.…”

Section: Fundamental Equationsmentioning

confidence: 99%

Robust Autoresonant Excitation in the Plasma Beat-Wave Accelerator

et al. 2004

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A modified version of the Plasma Beat-Wave Accelerator scheme is introduced and analyzed, which is based on autoresonant phase-locking of the nonlinear Langmuir wave to the slowly chirped beat frequency of the driving lasers via adiabatic passage through resonance. This new scheme is designed to overcome some of the well-known limitations of previous approaches, namely relativistic detuning and nonlinear modulation or other non-uniformity or non-stationarity in the driven Langmuir wave amplitude, and sensitivity to frequency mismatch due to measurement uncertainties and density fluctuations and inhomogeneities. As in previous schemes, modulational instabilities of the ionic background ultimately limit the useful interaction time, but nevertheless peak electric fields at or approaching the wave-breaking limit seem readily attainable. Compared to traditional approaches, the autoresonant scheme achieves larger accelerating electric fields for given laser intensity, or comparable fields for less laser power; the plasma wave excitation is much more robust to variations or uncertainties in plasma density; it is largely insensitive to the precise choice of chirp rate, provided only that chirping is sufficiently slow; and the quality and uniformity of the resulting plasma wave and its suitability for accelerator applications may be superior. In underdense plasmas, the total frequency shift required is only of the order of a few percent of the laser carrier frequency, and for possible experimental proofs-of-principle, the scheme might be implemented with relatively little additional modification to existing systems based on either solid-state amplifiers and Chirped Pulse Amplification techniques, or, with somewhat greater technological effort, using a CO2 or other gas laser system.

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“…Using .Eq. (14) , the thresholds for a number.of different modes in a magnetized plasma have been obtained (Porkolab 9 1 1~1 1 1 )…”

Section: Mn M4mentioning

confidence: 99%