Growth of a ring ripple on a Gaussian beam in a plasma

Sodha, M. S.; Sharma, Ashutosh; Prakash, Gyan; Verma, Manisha

doi:10.1063/1.1712976

Cited by 17 publications

(7 citation statements)

References 31 publications

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“…This assumption leads to the same dielectric function for both the ring ripple part as well as a Gaussian part of the electromagnetic beam and hence the same focusing factors (valid in the vicinity of the maximum of the ripple). This is in contrast to the earlier analyses [62][63][64][65][66][67][68][69], which separately consider the beam and the ripple, leading to incorrect results.…”

Section: Introductioncontrasting

confidence: 89%

“…The other approach is based on the direct [52,53] and indirect [54] evidence, suggesting that the filamentational instability in nonlinear media is caused by the occurrence of strong irradiance spikes, riding on an incident smooth-looking irradiance distribution in the plane, transverse to the direction of propagation. On the basis of the paraxial theory formulated by Akhmanov et al [55] and developed by Sodha et al [39,56], the growth of a Gaussian ripple on a plane uniform beam [57][58][59][60][61] and of a ring ripple on a Gaussian electromagnetic beam [62][63][64][65][66][67][68][69] in a plasma have been investigated to a significant extent. An interesting critique of the two approaches has been made by Sodha and Sharma [70].…”

Section: Introductionmentioning

confidence: 99%

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Focusing of a ring ripple on a Gaussian electromagnetic beam in a magnetoplasma

Misra¹,

Mishra²

2009

J. Plasma Phys.

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In this paper we present a theoretical investigation of the growth/propagation of a ring ripple, superposed on a Gaussian electromagnetic beam propagating along the direction of magnetic field in a magnetoplasma. The nature of propagation of the ripple is analysed in a paraxial-like approximation by radial expansion of the dielectric function, corresponding to the composite (Gaussian and ripple) electric field profile of the beam around the position of the maximum of the ripple. The two cases of collisional plasmas (with negligible thermal conduction) and collisionless plasmas (dominant ponderomotive nonlinearity) are considered. The effect of the magnetic field on the critical curves and focusing/defocusing of the ripple are studied and discussed.

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Section: Introductioncontrasting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Focusing of a ring ripple on a Gaussian electromagnetic beam in a magnetoplasma

Misra¹,

Mishra²

2009

J. Plasma Phys.

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“…(42a) and (42b) in Eq. (40) and equating the coefficient of r 2 , we obtain the dimensionless width parameters of the scattered beam (f S )…”

Section: Stimulated Raman Scaterringmentioning

confidence: 99%

Growth of ring ripple in a collisionless plasma in relativistic-ponderomotive regime and its effect on stimulated Raman backscattering process

Rawat¹,

Gauniyal

Purohit³

2014

Physics of Plasmas

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A theoretical and numerical study has been made of the propagation of a ring rippled laser beam in collisionless plasma with dominant relativistic ponderomotive nonlinearity and its effect on the excitation of electron plasma wave and stimulated Raman backscattering process. The growth of ring ripple, riding on an intense Gaussian laser beam in plasma has also been studied. A paraxial-ray and WKB approximation has been invoked to understand the nature of propagation of the ring rippled Gaussian laser beam in plasma, electron plasma wave and back reflectivity under the influence of both nonlinearities. The growth rate and focusing of a ring rippled beam is found to be considerably affected by the power of the main beam and the phase angle between the electric vectors of the main beam and the ring ripple. It has also been observed that the focusing is released by the coupling of relativistic and ponderomotive nonlinearities, which significantly affected the dynamics of the excitation of electron plasma wave and back reflectivity of stimulated Raman scattering (SRS). Due to the strong coupling between ring rippled laser beam and the excited electron plasma wave, back reflectivity of SRS is enhanced. It has been observed from the computational results that the effect of the increased intensity leads to suppression of SRS back reflectivity. The results have been presented for established laser and plasma parameters.

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“…Ponderomotive force is a nonlinear force that a charged particle experiences in an inhomogeneous oscillatory electromagnetic field, reforming the plasma electron density distribution and effective dielectric constant of medium, which has been extensively considered in ultraintense standing wave propagation, nonisothermal plasma, magnetoplasma, co-axial electromagnetic wave propagation, and ring ripple formation. [14][15][16][17][18][19][20] Malik and Aria presented the spatial electron density distribution in the microwave and plasma interaction for different electron temperatures, and they regarded the electrons equilibrated by ponderomotive force and plasma pressure gradient force as the starting point. 21 Drude model was first proposed by Paul and Drude in 1900 to explain the transport properties of electrons in materials.…”

Section: Introductionmentioning

confidence: 99%

Propagation of Gaussian laser beam in cold plasma of Drude model

et al. 2011

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The propagation characters of Gaussian laser beam in plasmas of Drude model have been investigated by complex eikonal function assumption. The dielectric constant of Drude model is representative and applicable in describing the cold unmagnetized plasmas. The dynamics of ponderomotive nonlinearity, spatial diffraction, and collision attenuation is considered. The derived coupling equations determine the variations of laser beam and irradiation attenuation. The modified laser beam-width parameter F, the dimensionless axis irradiation intensity I, and the spatial electron density distribution n/n0 have been studied in connection with collision frequency, initial laser intensity and beam-width, and electron temperature of plasma. The variations of laser beam and plasma density due to different selections of parameters are reasonably explained, and results indicate the feasible modification of the propagating characters of laser beam in plasmas, which possesses significance to fast ignition, extended propagation, and other applications.

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Growth of a ring ripple on a Gaussian beam in a plasma

Cited by 17 publications

References 31 publications

Focusing of a ring ripple on a Gaussian electromagnetic beam in a magnetoplasma

Focusing of a ring ripple on a Gaussian electromagnetic beam in a magnetoplasma

Growth of ring ripple in a collisionless plasma in relativistic-ponderomotive regime and its effect on stimulated Raman backscattering process

Propagation of Gaussian laser beam in cold plasma of Drude model

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