Stimulated Brillouin backscattering in magnetized plasmas

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Stimulated Brillouin backscattering (SBBS) of an extraordinary electromagnetic wave from a magnetized homogeneous plasma is investigated. A system of equations that describes the problem is derived and solved for a weak-field limit. A modified expression for the maximum growth rate in magnetized plasmas is derived, which recovers the growth rate expression for non-magnetized plasma known in literature. Small values of static magnetic field are found to increase the instability growth rate, while high magnetic fields reduce the instability bringing it to zero at a cutoff field, beyond which the plasma becomes stable, a result that is consistent with numerical results known in the literature (Bawa'aneh, M. S. 2003 Contrib. Plasma Phys. 43, 447). Also, a threshold for incident laser intensity is found, below which the SBBS maximum growth rate is suppressed. The value of this threshold is found to increase as the static magnetic field increases.

“…The dispersion relation of (16) is different from that obtained in [35]. Here, we used the Fourier transform to obtain this dispersion relation.…”

Section: Dispersion Relation For Brillouin Backscattering In Magnetizmentioning

confidence: 95%

Section: Dispersion Relation For Brillouin Backscattering In Magnetizmentioning

confidence: 99%

See 1 more Smart Citation

Stimulated Brillouin scattering of X-waves in magnetized plasma

Bawa’aneh¹

2006

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“…When this coupling takes place, various parametric instabilities, such as self-focusing, filamentation, stimulated Brillouin scattering (SBS), stimulated Raman scattering (SRS), etc. takes place [3][4][5][6][7][8][9]. These instabilities can reduce the laser plasma coupling efficiency and produce energetic electrons, which can preheat the fusion fuel and reduce the compression rate [10].…”

Section: Introductionmentioning

confidence: 99%

Filamentation of laser beam and suppression of stimulated Raman scattering due to localization of electron plasma wave

Purohit¹,

Sharma

2011

This paper presents the effect of laser beam filamentation on the localization of electron plasma wave (EPW) and stimulated Raman scattering (SRS) in unmagnetized plasma when relativistic and ponderomotive nonlinearities are operative. The splitted profile of the laser beam is obtained due to uneven focusing of the off-axial rays. The semi-analytical solution of the nonlinearly coupled EPW equation in the presence of laser beam filaments has been found. It is observed that due to this nonlinear coupling between these two waves, localization of EPW takes place. Stimulated Raman scattering of this EPW is studied and back reflectivity has been calculated. Further, the localization of EPW affects the eigenfrequency and damping of plasma wave. The new enhanced damping of the plasma wave has been calculated and it is found that the SRS process gets suppressed due to the localization of plasma wave in laser beam filamentary structures.

“…Those models include nonlinear frequency shift approximation [10] and high harmonic generation [11]. Also, SBS was described by Korteweg-De Vries equation [12] and, by many authors, by a system of fluid equations [13,14]. A mechanism, that could lead to the enhancement of the level of ion acoustic fluctuations is one triggered by the non-uniform heating of the target plasma by the interaction beam.…”

Section: Introductionmentioning

confidence: 99%

Enhanced levels of stimulated Brillouin reflectivity from non-Maxwellian plasmas

Bawa’aneh¹,

Boyd

2007

Abstract.A model that counts for temperature gradients in the target plasma, which leads to higher ion acoustic noise and enhanced levels of stimulated Brillouin scattering (SBS) gain and SBS reflectivity, has been adopted. Enhanced Brillouin gain leading to higher SBS reflectivity levels has been computed for non-homogeneous, non-Maxwellian plasmas. SBS reflectivity levels obtained are higher than those predicted by linear convective gain theory by several orders of magnitude and coincide with the high values of experimental data known in literature, which could not be interpreted by the linear convective gain theory.