The Propagation Properties of a Laguerre–Gaussian Beam in Nonlinear Plasma

2021 ◽  
Author(s):  
Suo Qiangbo ◽  
Yiping Han ◽  
Zhiwei Cui
Keyword(s):  
Gaussian Beam ◽  
Order Differential Equation ◽  
Plasma Temperature ◽  
Beam Width ◽  
The Self ◽  
Nonlinear Plasma ◽  
Vortex Charge ◽  
Self Focusing ◽  
Propagation Properties ◽  
Focusing Properties

Abstract The self-focusing properties of the Laguerre-Gaussian (LG) beam in nonlinear plasma, characterized by significant collisional or ponderomotive nonlinearity have been explored. The second-order differential equation of the beam width is established from Maxwell’s equations with Wentzel–Kramers–Brillouin (WKB) and paraxial like approximation. The effect of the vortex charge number, intensity parameter and plasma temperature on the self-focusing properties of the Laguerre-Gaussian beam has been investigated.

Combined influence of axial electron temperature and exponential plasma density ramp on the self-focusing of a chirped laser in plasma

2020 ◽  
Vol 75 (7) ◽  
pp. 671-675
Author(s):  
Niti Kant ◽  
Vishal Thakur
Keyword(s):  
Electron Temperature ◽  
Pulse Laser ◽  
Plasma Density ◽  
Beam Width ◽  
Spot Size ◽  
Higher Order ◽  
The Self ◽  
Chirped Pulse ◽  
Self Focusing ◽  
Paraxial Ray

AbstractAn analysis of the self-focusing of highly intense chirped pulse laser under exponential plasma density ramp with higher order value of axial electron temperature has been done. Beam width parameter is derived by using paraxial ray approximation and then solved numerically. It is seen that self-focusing of chirped pulse laser is intensely affected by the higher order values of axial electron temperature. Further, influence of exponential plasma density ramp is studied and it is concluded that self-focusing of laser enhances and occurs earlier. On the other hand defocusing of beam reduces to the great extent. It is noticed that the laser spot size reduces significantly under joint influence of the density ramp and the axial electron temperature. Present analysis may be useful for the analysis of quantum dots, the laser induced fusion and etc.

scholarly journals Focusing of Hermite-cosh-Gaussian laser beams in collisionless magnetoplasma

2010 ◽  
Vol 28 (2) ◽  
pp. 343-349 ◽  
Author(s):  
S.D. Patil ◽  
M.V. Takale ◽  
S.T. Navare ◽  
M.B. Dongare
Keyword(s):  
Beam Width ◽  
The Self ◽  
Laser Beams ◽  
Combined Effects ◽  
Dimensionless Distance ◽  
Self Focusing ◽  
Mode Index ◽  
Ponderomotive Nonlinearity

AbstractThis paper presents an investigation of the focusing of Hermite-cosh-Gaussian laser beams in magneto-plasma by considering ponderomotive nonlinearity. The dynamics of the combined effects of nonlinearity and spatial diffraction is presented. To highlight the nature of focusing, plot of beam-width parameter vs. dimensionless distance of propagation has been obtained. The effect of mode index and decentered parameter on the self-focusing of the beams has been discussed.

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.

scholarly journals Relativistic and ponderomotive self-focusing of a laser pulse in magnetized plasma

2012 ◽  
Vol 30 (4) ◽  
pp. 659-664 ◽  
Author(s):  
Anamika Sharma ◽  
V.K. Tripathi
Keyword(s):  
Laser Pulse ◽  
Cyclotron Frequency ◽  
Ponderomotive Force ◽  
Beam Width ◽  
Laser Frequency ◽  
Electron Cyclotron ◽  
The Self ◽  
Magnetized Plasma ◽  
Electron Cyclotron Frequency ◽  
Self Focusing

AbstractThe self-focusing of an intense right circularly polarized Gaussian laser pulse in magnetized plasma is studied. The ions are taken to be immobile and relativistic mass effect is incorporated in both the plasma frequency (ωp) and the electron cyclotron frequency (ωc) while determining the ponderomotive force on electrons. The ponderomotive force causes electron expulsion when the effective electron cyclotron frequency is below twice the laser frequency. The nonlinear plasma dielectric function due to ponderomotive and relativistic effects is derived, which is then employed in beam-width parameter equation to study the self-focusing of the laser beam. From this, we estimate the importance of relativistic self-focusing in comparison with ponderomotive self-focusing at moderate laser intensities. The beam width parameter decreases with magnetic field indicating better self-focusing. When the laser intensity is very high, the relativistic gamma factor can be modeled as ${\rm \gamma} = 0.8\left({{{{\rm \omega} _c } / {\rm \omega} }} \right)+ \sqrt {1 + a_0^2 }$γ=0.8(ωc/ω)+1+a02 where ω and a0 are the laser frequency and the normalized laser field strength, respectively. The cyclotron effects on the self-focusing of laser pulse are reduced at high field strengths.

scholarly journals Self-Focusing Property of Partially Coherent Beam With Non-Uniform Correlation Structure in Non-Linear Media

2022 ◽  
Vol 9 ◽  
Author(s):  
Lu Lu ◽  
Zhiqiang Wang ◽  
Jiayi Yu ◽  
Chunhong Qiao ◽  
Rong Lin ◽  
...  
Keyword(s):  
Beam Width ◽  
Vital Role ◽  
Coherent Beam ◽  
The Self ◽  
Correlation Structure ◽  
Threshold Condition ◽  
Partially Coherent ◽  
Self Focusing ◽  
Non Linear ◽  
Focusing Property

Coherence in a light beam has the potential to serve as a degree of freedom for manipulating the beam. In this work, the self-focusing property of a partially coherent beam with a non-uniform correlation structure propagating in a non-linear medium is investigated. The analysis of the evolution of beam width reveals that the coherence structure plays a vital role in the self-focusing formation. A threshold condition for the coherence radius is proposed for the first time, and the relation of self-focusing length and initial coherence radius is studied numerically and analytically. It is shown that a feasible approach for manipulating the self-focusing length by adjusting the initial coherence radius is achieved.

Gaussian beam evolution in nonlinear inhomogeneous plasma

2014 ◽  
Vol 80 (2) ◽  
pp. 197-214
Author(s):  
P. Berczynski ◽  
Yu. A. Kravtsov ◽  
V. Tikhonchuk
Keyword(s):  
Plasma Physics ◽  
Gaussian Beam ◽  
Wave Front ◽  
Plasma Layer ◽  
Plasma Heating ◽  
Inhomogeneous Plasma ◽  
Nonlinear Refraction ◽  
Beam Width ◽  
Axially Symmetric ◽  
Self Focusing

AbstractThe method of nonlinear complex geometrical optics (NCGO) is proposed in this paper for description of the evolution of a spatially narrow Gaussian beam (GB) in an inhomogeneous nonlinear plasma. NCGO method deals with first-order ordinary differential equations for the complex curvature of the wave front and for GB amplitude and for second-order ordinary differential equation for GB width. Thus, NCGO simplifies the description of GB diffraction and self-focusing effects as compared to the known methods of plasma physics and this way it can be assumed to be attractive and comprehensive approach in problems of plasma heating by electromagnetic waves. Moreover, we demonstrate in this paper some regularity for nonlinear inhomogeneous plasma in the framework of which central ray of a GB is not subjected to nonlinear refraction within NCGO method boundary applicability. On the contrary, the beam width, wave front curvature, and GB amplitude are modified by diffraction and self-focusing processes. General properties of the beam propagation are illustrated with results of numerical modeling for two particular cases: GB diffraction and self-focusing along curvilinear trajectory with torsion in axially symmetric plasma column and GB reflection from nonlinear inhomogeneous plasma layer. We prove in this paper that NCGO is new effective method of plasma physics, which can be applied for improvement of ray tracing techniques and plasma diagnostics.

scholarly journals Focusing properties and focal shift of vortex Hermite-cosh- Gaussian beams

2021 ◽  
Author(s):  
Zoubir Hricha ◽  
El Mostapha El Halba ◽  
Abdelmajid Belafhal
Keyword(s):  
Beam Width ◽  
Spot Size ◽  
Focal Region ◽  
Beam Spot ◽  
Fresnel Number ◽  
Beam Focusing ◽  
Vortex Charge ◽  
Focal Shift ◽  
Beam Parameters ◽  
Focusing Properties

Abstract In this work, we investigate the focusing properties of a vortex Hermite-cosh-Gaussian beam (vHChGB) passing through a converging lens system. The analytical propagation equation as well as the beam width expression of a focused vHChGB is derived based on the Huygens-Fresnel diffraction principle. From the obtained formulae, the effects of the Gaussian Fresnel number NF and the beam parameters on the structure of the light intensity distribution and the beam spot size in the focal region are analyzed numerically. It is shown that the focal shift, which is determined from the minimum beam spot width criterion, is affected strongly by the change of the Fresnel number, the parameter b, and it is slightly altered by the vortex charge M and nearly insensitive to the beam order n. For a fixed value of NF, the focal shift is smaller when the parameter b or the vortex charge M is larger. The focal shift decreases monotonously with the increase of Fresnel number until it vanishes asymptotically for large NF. The obtained results may be useful for the applications of the vHChGBs in beam shaping and beam focusing.

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