scholarly journals Spatial evolution of a q-Gaussian laser beam in relativistic plasma

2010 ◽  
Vol 28 (3) ◽  
pp. 479-489 ◽  
Author(s):  
A. Sharma ◽  
I. Kourakis
Keyword(s):  
Laser Beam ◽  
Beam Profile ◽  
Relativistic Plasma ◽  
Gaussian Laser Beam ◽  
Transverse Beam ◽  
Recent Experimental Study ◽  
Gaussian Profile ◽  
Spatial Beam ◽  
Gaussian Distribution Function ◽  
Non Gaussian

AbstractIn a recent experimental study, the beam intensity profile of the Vulcan petawatt laser beam was measured; it was found that only 20% of the energy was contained within the full width at half maximum of 6.9 μm and 50% within 16 μm, suggesting a long-tailed non-Gaussian transverse beam profile. A q-Gaussian distribution function was suggested therein to reproduce this behavior. The spatial beam profile dynamics of a q-Gaussian laser beam propagating in relativistic plasma is investigated in this article. A non-paraxial theory is employed, taking into account nonlinearity via the relativistic decrease of the plasma frequency. We have studied analytically and numerically the dynamics of a relativistically guided beam and its dependence on the q-parameter. Numerical simulation results are shown to trace the dependence of the focusing length on the q-Gaussian profile.

Generation of Efficient Terahertz Radiation by Relativistic Self-Focusing of A Cosh-Gaussian Laser Beam in A Magnetized Plasma

2021 ◽  
Author(s):  
Gunjan Purohit ◽  
Bineet Gaur ◽  
Pradeep Kothiyal ◽  
Amita Raizada
Keyword(s):  
Laser Beam ◽  
Numerical Study ◽  
The Self ◽  
Magnetized Plasma ◽  
Thz Radiation ◽  
Gaussian Laser Beam ◽  
Plasma Parameters ◽  
Gaussian Profile ◽  
Self Focusing ◽  
Incident Laser Intensity

Abstract This paper presents a scheme for the generation of terahertz (THz) radiation by self-focusing of a cosh-Gaussian laser beam in the magnetized and rippled density plasma, when relativistic nonlinearity is operative. The strong coupling between self-focused laser beam and pre-existing density ripple produces nonlinear current that originates THz radiation. THz radiation is produced by the interaction of the cosh-Gaussian laser beam with electron plasma wave under the appropriate phase matching conditions. Expressions for the beamwidth parameter of cosh-Gaussian laser beam and the electric vector of the THz radiation have been obtained using higher-order paraxial theory and solved numerically. The self-focusing of the cosh-Gaussian laser beam and its effect on the generated THz amplitude have been studied for specific laser and plasma parameters. Numerical study has been performed on various values of the decentered parameter, incident laser intensity, magnetic field, and relative density. The results have also been compared with the paraxial region as well as the Gaussian profile of laser beam. Numerical results suggest that the self-focusing of the cosh-Gaussian laser beam and the amplitude of THz radiation increase in the extended paraxial region compared to the paraxial region. It is also observed that the focusing of the cosh-Gaussian laser beam in the magnetized plasma and the amplitude of the THz radiation increases at higher values of the decentered parameter.

scholarly journals Generalized Thermoelastic Functionally Graded on a Thin Slim Strip Non-Gaussian Laser Beam

Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1094 ◽  
Author(s):  
Sayed M. Abo-Dahab ◽  
Ahmed E. Abouelregal ◽  
Marin Marin
Keyword(s):  
Laser Beam ◽  
Pulse Length ◽  
Generalized Thermoelasticity ◽  
Functionally Graded ◽  
Strong Impact ◽  
Problem Solution ◽  
Gaussian Laser Beam ◽  
Laser Parameters ◽  
Non Gaussian ◽  
The Impact

The present study utilizes the generalized thermoelasticity theory, with one thermal relaxation time (TR), to examine the thermoelastic problem of a functionally graded thin slim strip (TSS). The authors heated the plane surface bounding using a non-Gaussian laser beam with a pulse length of 2 ps. The material characteristics varied continually based on exponential functions. Moreover, the equations governing the generalized thermoelasticity for a functionally graded material (FGM) are recognized. The problem’s ideal solution was primarily obtained in the Laplace transform (LT) space. The LTs were converted numerically because of the considerable importance of the response in the transient state. For a hypothetical substance, the numerical procedures calculating the displacement, stress, temperature and strain were given. The analogous problem solution to an isotropic homogeneous material was provided by defining the parameter of non-homogeneity adequately. The obtained results were displayed using graphs to illustrate the extent to which non-homogeneity affected displacement, stress, temperature and strain. A comparison was been made between the present study and those previously obtained by others, when the new parameters vanish to show the impact of the non-homogeneity, TSS and laser parameters on the phenomenon. The results obtained indicate a significant strong impact of FGM, TSS and laser parameters.

Spatial Dependence of Inverse Raman Signals

1981 ◽  
Vol 35 (6) ◽  
pp. 591-593 ◽  
Author(s):  
Gregory R. Daigneault ◽  
Michael D. Morris
Keyword(s):  
Laser Beam ◽  
Spatial Dependence ◽  
Potassium Nitrate ◽  
Test System ◽  
Pulsed Dye Laser ◽  
Raman Signal ◽  
Gaussian Beams ◽  
Gaussian Profile ◽  
Non Gaussian ◽  
Signal Intensities

The spatial dependence of inverse Raman signal intensities was investigated. Aqueous 0.5 M potassium nitrate in cells ranging from 1 to 50 mm was used as the test system. Three focusing lenses were used. The data do not fit the arctan dependence derived for Gaussian beams. The deviations are ascribed to the non-Gaussian profile of the pulsed dye laser beam.

Gaussian laser beam profile shaping

1996 ◽  
Vol 35 (11) ◽  
pp. 3285 ◽  
Author(s):  
Fred M. Dickey
Keyword(s):  
Laser Beam ◽  
Beam Profile ◽  
Gaussian Laser Beam ◽  
Laser Beam Profile

EFFECTS OF COMBINED RADIATIVE AND CONVECTIVE HEAT TRANSFER ON TEMPERATURE BENEATH MODULATED SOURCE

2007 ◽  
Vol 21 (11) ◽  
pp. 1903-1913 ◽  
Author(s):  
KAREM BOUBAKER ◽  
M. BOUHAFS
Keyword(s):  
Heat Transfer ◽  
Analytical Solution ◽  
Laser Beam ◽  
Heat Equation ◽  
Convective Heat Transfer ◽  
Temperature Profile ◽  
Convective Heat ◽  
Calculation Method ◽  
Gaussian Laser Beam ◽  
Non Gaussian

An analytical solution is presented to the heat equation in the vicinity of a surface fluid, heated by a modulated Gaussian Laser beam and taking into account three heat transfer modes: conduction, radiation and convection. A new calculation method is performed for profiling temperature inside a surface fluid. Comparison with several experimental profiles explains some unexpected temperature profile results as non-Gaussian behaviour.

Sign in / Sign up

Export Citation Format

Share Document