Propagation characters of Gaussian laser beams in collisionless plasma: Effect of plasma temperature

2011 ◽  
Vol 18 (4) ◽  
pp. 043101 ◽  
Author(s):  
Ying Wang ◽  
Zhongxiang Zhou
Keyword(s):  
Collisionless Plasma ◽  
Plasma Temperature ◽  
Laser Beams ◽  
Plasma Effect

An analytical investigation of the optical mixing of two laser beams of identical frequencies in a spatially homogeneous collisionless plasma

1976 ◽  
Vol 54 (24) ◽  
pp. 2387-2395
Author(s):  
Orestes Spyrou ◽  
Jochen Meyer
Keyword(s):  
Electric Field Intensity ◽  
Collisionless Plasma ◽  
Charged Particles ◽  
Elliptic Functions ◽  
Particle Dynamics ◽  
Analytical Investigation ◽  
Laser Beams ◽  
Wave Number ◽  
Optical Mixing ◽  
Spatially Homogeneous

Two laser beams of the same frequency and intensity propagating in opposite directions are mixed in a uniform collisionless plasma.A standing longitudinal wave of wave number k0 = 2kL (kL being the wave number of one of the lasers) is excited and traps charged particles. Including trapped particle dynamics and making use of the properties of the Jacobi elliptic functions, an expression for the power P(t) and the energy. ΔU0 absorbed by the plasma electrons is derived. It is found that the power varies sinusoidally with time. Then the energy density ΔU0 is plotted as a function of the variable E10/kL, E10 being the electric field intensity of the lasers, and the validity of the results is discussed.

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 Numerical programming of self-focusing at laser–plasma interaction

2000 ◽  
Vol 18 (1) ◽  
pp. 59-72 ◽  
Author(s):  
F. OSMAN ◽  
R. CASTILLO ◽  
H. HORA
Keyword(s):  
Collisionless Plasma ◽  
Relativistic Effects ◽  
Laser Beams ◽  
Moderate Intensity ◽  
Lateral Direction ◽  
Laser Plasma Interaction ◽  
Relativistic Mass ◽  
Self Focusing ◽  
Wide Range ◽  
Nonlinear Force

This paper presents an investigation into the behavior of a laser beam of finite diameter in plasma with respect to forces and optical properties, which lead to self-focusing of the beam. The transient setting of ponderomotive nonlinearity in a collisionless plasma has been studied, and consequently the self-focusing of the pulse, and the focusing of the plasma wave occurs. The description of a self-focusing mechanism of laser radiation in the plasma due to nonlinear forces acting on the plasma in the lateral direction, relative to the laser has been investigated in the nonrelativistic regime. The behavior of the laser beams in plasma, which is the domain of self-focusing at high or moderate intensity, is dominated by the nonlinear force. The investigation of self-focusing processes of laser beams in plasma results from the relativistic mass and energy dependency of the refractive index at high laser intensities. Here, the relativistic effects are considered to evaluate the relativistic self-focusing lengths for the Nd glass radiation, at different plasma densities of various laser intensities. A numerical program in c++ that incorporates both the ponderomotive force in self-focusing mechanism and relativistic effects has been developed to explore in depth self-focusing over a wide range of parameters.

Cross Focusing of two Coaxial Gaussian Beams with Relativistic and Ponderomotive Nonlinearity

2012 ◽  
Vol 67 (1-2) ◽  
pp. 10-14
Author(s):  
Prerana Sharma
Keyword(s):  
Laser Beam ◽  
Collisionless Plasma ◽  
Laser Beams ◽  
Fourth Power ◽  
Gaussian Beams ◽  
Wave Processes ◽  
Plasma Parameters ◽  
Ponderomotive Nonlinearity ◽  
Paraxial Ray ◽  
Pump Laser Beam

This paper presents the cross focusing of two high power lasers by taking off-axial contributions of the laser beams in a collisionless plasma. Due to relativistic and ponderomotive nonlinearities the two laser beams affect the dynamics of each other and cross focusing takes place. The expressions for the laser beam intensities by using the eikonal method are derived. The contributions of the r2 and r4 terms are incorporated. By expanding the eikonal and the other relevant quantities up to the fourth power of r, the solution of the pump laser beam is obtained within the extended paraxial ray approximation. Filamentary structures of the laser beams are observed due to the relativistic and the ponderomotive nonlinearity. The focusing of the laser beams is shown to become fast in the extended paraxial region. Using the laser beam and the plasma parameters, appropriate for beat wave processes, the filaments of the laser beams are studied and the relevance of these results to beat wave processes is pointed out.

scholarly journals Domains of modulation parameter in the interaction of finite Airy–Gaussian laser beams with plasma

2020 ◽  
Vol 38 (3) ◽  
pp. 204-210
Author(s):  
V. S. Pawar ◽  
S. R. Kokare ◽  
S. D. Patil ◽  
M. V. Takale
Keyword(s):  
Absorption Coefficient ◽  
Collisionless Plasma ◽  
Beam Width ◽  
The Self ◽  
Laser Beams ◽  
Linear Absorption Coefficient ◽  
Linear Absorption ◽  
Self Focusing ◽  
Modulation Parameter ◽  
Paraxial Ray

AbstractIn this paper, self-focusing of finite Airy–Gaussian (AiG) laser beams in collisionless plasma has been investigated. The source of nonlinearity considered herein is relativistic. Based on the Wentzel–Kramers–Brillouin (WKB) and paraxial-ray approximations, the nonlinear coupled differential equations for beam-width parameters in transverse dimensions of AiG beams have been established. The effect of beam's modulation parameter and linear absorption coefficient on the self-focusing/defocusing of the beams is specifically considered. It is found that self-focusing/defocusing of finite AiG beams depends on the range of modulation parameter. The extent of self-focusing is found to decrease with increase in absorption.

Self-focusing and defocusing of TEM0p Hermite–Gaussian laser beams in collisionless plasma

2009 ◽  
Vol 282 (15) ◽  
pp. 3157-3162 ◽  
Author(s):  
M.V. Takale ◽  
S.T. Navare ◽  
S.D. Patil ◽  
V.J. Fulari ◽  
M.B. Dongare
Keyword(s):  
Collisionless Plasma ◽  
Laser Beams ◽  
Self Focusing

scholarly journals Turbulence and Particle Acceleration in a Relativistic Plasma

2022 ◽  
Vol 924 (1) ◽  
pp. L19
Author(s):  
Cristian Vega ◽  
Stanislav Boldyrev ◽  
Vadim Roytershteyn ◽  
Mikhail Medvedev
Keyword(s):  
Distribution Function ◽  
Energy Distribution ◽  
Power Law ◽  
Numerical Study ◽  
Collisionless Plasma ◽  
Plasma Temperature ◽  
Particle Energy ◽  
Energy Distribution Function ◽  
Scaling Exponent ◽  
Magnetic Perturbations

Abstract In a collisionless plasma, the energy distribution function of plasma particles can be strongly affected by turbulence. In particular, it can develop a nonthermal power-law tail at high energies. We argue that turbulence with initially relativistically strong magnetic perturbations (magnetization parameter σ ≫ 1) quickly evolves into a state with ultrarelativistic plasma temperature but mildly relativistic turbulent fluctuations. We present a phenomenological and numerical study suggesting that in this case, the exponent α in the power-law particle-energy distribution function, f(γ)d γ ∝ γ −α d γ, depends on magnetic compressibility of turbulence. Our analytic prediction for the scaling exponent α is in good agreement with the numerical results.

scholarly journals Particle acceleration by beating of two intense cross-focused cosh-Gaussian laser beams in plasma

2018 ◽  
Vol 36 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Bineet Gaur ◽  
Priyanka Rawat ◽  
Gunjan Purohit
Keyword(s):  
Particle Acceleration ◽  
Plasma Wave ◽  
Collisionless Plasma ◽  
Laser Beams ◽  
Gaussian Beams ◽  
Plasma Parameters ◽  
Remarkable Change ◽  
Relativistic Case ◽  
Electron Plasma Wave ◽  
Gaussian Profile

AbstractThe effect of two intense cross-focused cosh-Gaussian laser (CGL) beams on the generation of electron plasma wave (EPW) and particle acceleration in collisionless plasma has been investigated under the relativistic–ponderomotive regime. Due to mutual interaction of two laser beams, cross-focusing takes place in plasma. The EPW is generated by the beating of two cross-focused CGL beams of frequencies ω1 and ω2. An analytical expression for the beamwidth of laser beams and EPW as well as the power of the generated EPW has been evaluated using Wentzel–Kramers–Brillouin and paraxial approximations. The energy of the accelerated electrons by the beat-wave process has also been calculated. Numerical simulations have been carried out to investigate the effect of typical laser plasma parameters on the power of excited EPW and acceleration of electrons. The results are compared with only relativistic nonlinearity and the Gaussian profile of laser beams. It is observed that CGL beams focused earlier than Gaussian beams, which significantly affected the dynamics of plasma wave excitation and particle acceleration. Numerical results indicate that there is a remarkable change in the power of generated EPW and electron acceleration in the relativistic–ponderomotive case in comparison with only relativistic case.

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