Effect of laser beam filamentation on plasma wave localization and electron heating

2007 ◽  
Vol 14 (10) ◽  
pp. 103112 ◽  
Author(s):  
R. P. Sharma ◽  
Prerana Sharma ◽  
P. K. Chauhan
Keyword(s):  
Laser Beam ◽  
Plasma Wave ◽  
Wave Localization ◽  
Electron Heating

Transverse plasma-wave localization in multiple dimensions

2011 ◽  
Vol 83 (4) ◽  
Author(s):  
J. E. Fahlen ◽  
B. J. Winjum ◽  
T. Grismayer ◽  
W. B. Mori
Keyword(s):  
Plasma Wave ◽  
Wave Localization ◽  
Multiple Dimensions

Effect of relativistic self-focusing on plasma wave excitation by a hollow Gaussian beam

2011 ◽  
Vol 77 (6) ◽  
pp. 777-784 ◽  
Author(s):  
RUCHIKA GUPTA ◽  
M. RAFAT ◽  
R. P. SHARMA
Keyword(s):  
Laser Beam ◽  
Gaussian Beam ◽  
Plasma Wave ◽  
Radial Distance ◽  
Laser Frequency ◽  
Pump Laser ◽  
Wave Excitation ◽  
Paraxial Ray Approximation ◽  
Self Focusing ◽  
Paraxial Ray

AbstractA paraxial-like approach has been invoked to understand the nature of propagation of a hollow Gaussian beam (HGB) propagating in plasma under the influence of relativistic non-linearity. In this approach, the parameters are expanded in terms of the radial distance from the maximum of irradiance rather than that from the axis. This paper investigates the excitation of plasma wave in a hot collision less plasma by HGB. On account of the × force, a plasma wave at 2ω0 (here, ω0 is the pump laser frequency) is generated. The solution of the HGB has been obtained within the paraxial ray approximation. Filamentary structures of the laser beam are observed due to relativistic non-linearity.

scholarly journals Effect of self-focused cosh Gaussian laser beam on the excitation of electron plasma wave and particle acceleration

2016 ◽  
Vol 34 (4) ◽  
pp. 621-630 ◽  
Author(s):  
B. Gaur ◽  
P. Rawat ◽  
G. Purohit
Keyword(s):  
Particle Acceleration ◽  
Laser Beam ◽  
Plasma Wave ◽  
Electron Plasma ◽  
The Self ◽  
Acceleration Process ◽  
Gaussian Laser Beam ◽  
Electron Plasma Wave ◽  
Self Focusing ◽  
Paraxial Ray

AbstractThis work presents an investigation of the self-focusing of a high-power laser beam having cosh Gaussian intensity profile in a collissionless plasma under weak relativistic-ponderomotove (RP) and only relativistic regimes and its effect on the excitation of electron plasma wave (EPW), and particle acceleration process. Nonlinear differential equations have been set up for the beam width and intensity of cosh Gaussian laser beam (CGLB) and EPW using the Wentzel-Kramers-Brillouin and paraxial-ray approximations as well as fluid equations. The numerical results are presented for different values of decentered parameter ‘b’ and intensity parameter ‘a’ of CGLB. Strong self-focusing is observed in RP regime as compared with only relativistic nonlinearity. Numerical analysis shows that these parameters play crucial role on the self-focusing of the CGLB and the excitation of EPW. It is also found that the intensity/amplitude of EPW increases with b and a. Further, nonlinear coupling between the CGLB and EPW leads to the acceleration of electrons. The intensity of EPW and energy gain by electrons is significantly affected by including the ponderomotive nonlinearity. The energy of the accelerated electrons is increased by increasing the value of ‘b’. The results are presented for typical laser and plasma parameters.

scholarly journals Enhanced Raman scattering of a rippled laser beam in a magnetized collisional plasma

2004 ◽  
Vol 22 (1) ◽  
pp. 35-40 ◽  
Author(s):  
NARESHPAL SINGH SAINI ◽  
TARSEM SINGH GILL
Keyword(s):  
Raman Scattering ◽  
Laser Beam ◽  
Plasma Wave ◽  
Scattered Wave ◽  
Electron Plasma ◽  
Main Beam ◽  
Stimulated Scattering ◽  
Electron Plasma Wave ◽  
Scattered Power ◽  
Enhanced Raman Scattering

In the laser–plasma interaction experiments, self-focusing and filamentation affect quite a large number of other parametric processes including stimulated scattering processes. Nonlinearity considered in the present problem is the collisional type. The coupling between the main beam, ripple, and excited electron plasma wave is strong. Authors have investigated the growing interaction of a rippled laser beam with an electron plasma wave leading to enhanced Raman scattering. An expression for scattered power is derived and the effect of the externally applied magnetic field on the enhancement of scattered power is observed. From computational results, it is observed that the effect of increased intensity of the main beam leads to suppression of power associated with the Raman scattered wave.

scholarly journals Higher harmonic generation by self-focused q-Gaussian laser beam in preformed collisionless plasma channel

2014 ◽  
Vol 32 (4) ◽  
pp. 621-629 ◽  
Author(s):  
Arvinder Singh ◽  
Naveen Gupta
Keyword(s):  
Differential Equation ◽  
Laser Beam ◽  
Plasma Wave ◽  
Harmonic Generation ◽  
Plasma Channel ◽  
Field Region ◽  
Incident Laser Beam ◽  
Gaussian Laser Beam ◽  
Incident Laser ◽  
Higher Harmonic

AbstractThis paper presents an investigation of self-focusing of a q-Gaussian laser beam and its effect on harmonic generation in a preformed collisionless parabolic plasma channel. In the presence of a q-Gaussian laser beam, the carriers get redistributed from high field region to low field region on account of ponderomotive force as a result of which a transverse density gradient is produced in the channel which in turn generates plasma wave at pump frequency. Generated plasma wave interacts with the incident laser beam and generate higher harmonics of the incident laser beam. Moment theory has been used to derive differential equation for the spot size of laser beam propagating through the channel. The differential equation so obtained has been solved numerically. The effect of the intensity of laser beam, deviation of intensity distribution of laser beam along its wave front from Gaussian distribution, plasma density and depth of channel on beam width of laser beam and harmonic yield has been investigated. The effect of order of higher harmonic on harmonic yield has been also investigated.

scholarly journals Electron plasma wave excitation by beating of two q-Gaussian laser beams in collisionless plasma

2016 ◽  
Vol 34 (2) ◽  
pp. 230-241 ◽  
Author(s):  
Arvinder Singh ◽  
Naveen Gupta
Keyword(s):  
Laser Beam ◽  
Plasma Wave ◽  
Electron Concentration ◽  
Collisionless Plasma ◽  
Electron Plasma ◽  
Spot Size ◽  
Laser Beams ◽  
Plasma Parameters ◽  
Electron Plasma Wave ◽  
Ponderomotive Nonlinearity

AbstractThis paper presents a scheme for excitation of an electron-plasma wave (EPW) by beating two q-Gaussian laser beams in an underdense plasma where ponderomotive nonlinearity is operative. Starting from nonlinear Schrödinger-type wave equation in Wentzel–Kramers–Brillouin (WKB) approximation, the coupled differential equations governing the evolution of spot size of laser beams with distance of propagation have been derived. The ponderomotive nonlinearity depends not only on the intensity of first laser beam, but also on that of second laser beam. Therefore, the dynamics of one laser beam affects that of other and hence, cross-focusing of the two laser beams takes place. Due to nonuniform intensity distribution along the wavefronts of the laser beams, the background electron concentration is modified. The amplitude of EPW, which depends on the background electron concentration, is thus nonlinearly coupled with the laser beams. The effects of ponderomotive nonlinearity and cross-focusing of the laser beams on excitation of EPW have been incorporated. Numerical simulations have been carried out to investigate the effect of laser and plasma parameters on cross-focusing of the two laser beams and further its effect on EPW excitation.

scholarly journals Direct Electron Acceleration By An Intense Nonparaxial Cosh-Gaussian Laser Beam Driven Electron Plasma Wave in Plasma

2021 ◽  
Author(s):  
Gunjan Purohit ◽  
Bineet Gaur ◽  
Amita Raizada ◽  
Pradeep Kothiyal
Keyword(s):  
Laser Beam ◽  
Plasma Wave ◽  
Electron Acceleration ◽  
Electron Plasma ◽  
Acceleration Process ◽  
Gaussian Laser Beam ◽  
Plasma Parameters ◽  
Electron Plasma Wave ◽  
Self Focusing ◽  
Paraxial Ray

Abstract Excitation of electron plasma wave by an intense short laser pulse is relevant to electron acceleration process in laser plasma interactions. In this work, the self-focusing of an intense cosh-Gaussian laser beam in collissionless plasma have been studied in the non-paraxial region with relativistic and ponderomotive nonlinearities. Further, the effect of self-focusing of the cosh-Gaussian laser beam on the excitation of electron plasma wave and on subsequent electron acceleration has been investigated. Analytical expressions for the beam width parameter/intensity of cosh-Gaussian laser beam and the electron plasma wave have been established and solved numerically. The energy of the accelerated electrons has also been obtained. The strong self-focusing of the cosh-Gaussian laser beam in plasmas stimulates a large amplitude electron plasma wave, which further accelerates the electrons. The well-established laser and plasma parameters have been used in numerical computation. The results have been compared with paraxial ray approximation, Gaussian profile of laser beam and only with the relativistic nonlinearity. Numerical results suggest that the focusing of the cosh-Gaussian laser beam, the amplitude of electron plasma wave, and energy gain by electrons increases in non-paraxial region, when relativistic and ponderomotive nonlinearities are simultaneously operative. In addition, it has also been observed that the electron plasma wave is driven more efficiently by a cosh-Gaussian laser beam that accelerates plasma electrons to higher energies.

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