Deformation of a liquid surface by laser heating: laser-beam self-focusing and generation of capillary waves

1986 ◽  
Vol 64 (9) ◽  
pp. 1341-1344 ◽  
Author(s):  
J. Hartikainen ◽  
J. Jaarinen ◽  
M. Luukkala
Keyword(s):  
Laser Beam ◽  
Laser Heating ◽  
Surface Deformation ◽  
Liquid Surface ◽  
Capillary Waves ◽  
The Self ◽  
Self Focusing

The surface deformation of oil by laser heating is presented. The self-focusing of the reflected beam and the generation of capillary waves are observed.

Relativistic self-focusing of a rippled laser beam in a plasma

1999 ◽  
Vol 62 (4) ◽  
pp. 389-396 ◽  
Author(s):  
M. V. ASTHANA ◽  
A. GIULIETTI ◽  
DINESH VARSHNEY ◽  
M. S. SODHA
Keyword(s):  
Refractive Index ◽  
Laser Beam ◽  
The Self ◽  
Laser Beams ◽  
Radial Dependence ◽  
Main Beam ◽  
Gaussian Laser Beam ◽  
Self Focusing ◽  
Saturation Effects ◽  
Paraxial Ray

This paper presents an analysis of the relativistic self-focusing of a rippled Gaussian laser beam in a plasma. Considering the nonlinearity as arising owing to relativistic variation of mass, and following the WKB and paraxial-ray approximations, the phenomenon of self-focusing of rippled laser beams is studied for arbitrary magnitude of nonlinearity. Pandey et al. [Phys. Fluids82, 1221 (1990)] have shown that a small ripple on the axis of the main beam grows very rapidly with distance of propagation as compared with the self-focusing of the main beam. Based on this analogy, we have analysed relativistic self-focusing of rippled beams in plasmas. The relativistic intensities with saturation effects of nonlinearity allow the nonlinear refractive index in the paraxial regime to have a slower radial dependence, and thus the ripple extracts relatively less energy from its neighbourhood.

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.

Effect of a strong magnetic field on the self-focusing of a laser beam in InSb

1977 ◽  
Vol 40 (1) ◽  
pp. 315-320
Author(s):  
M. S. Sodha ◽  
V. K. Tripathi ◽  
D. P. Singh
Keyword(s):  
Magnetic Field ◽  
Laser Beam ◽  
Strong Magnetic Field ◽  
The Self ◽  
Self Focusing

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.

Relativistic cross-focusing of two coaxial Gaussian laser beams in a plasma

1998 ◽  
Vol 60 (4) ◽  
pp. 811-818 ◽  
Author(s):  
RAJ KUMAR ◽  
H. D. PANDEY ◽  
R. P. SHARMA ◽  
M. KUMAR
Keyword(s):  
Laser Beam ◽  
Relativistic Effect ◽  
Laser Pulses ◽  
The Self ◽  
Laser Beams ◽  
Particle Accelerators ◽  
Wave Excitation ◽  
Homogeneous Plasma ◽  
Self Focusing ◽  
Ponderomotive Nonlinearity

The paper presents a paraxial theory of the relativistic cross-focusing of two coaxial Gaussian laser beams of different frequencies in a homogeneous plasma. We discuss the self-focusing of a weaker laser beam in the plasma due to the optical inhomogeneities introduced by another stronger copropagating laser beam. In the presence of the second stronger beam (Pcr21<P2<Pcr22), the plasma behaves as an oscillatory waveguide for the first, weaker, beam (P1<Pcr11) as it propagates in the plasma. When both the beams are strong (Pcr11,21<P1,2<Pcr12,22), the nonlinearities introduced by the relativistic effect are additive in nature, such that one beam can undergo oscillatory self-focusing and the other simultaneously defocusing, and vice versa. A comparison reveals that cross-focusing due to relativistic nonlinearity is possible for a wider range of powers of the laser pulses than is cross-focusing due to ponderomotive nonlinearity. Relativistic cross-focusing is important in plasma beat-wave excitation and collective laser particle accelerators.

Generation of polarization singularities in the self-focusing of an elliptically polarized laser beam in an isotropic Kerr medium

2016 ◽  
Vol 332 ◽  
pp. 73-78 ◽  
Author(s):  
N.A. Panov ◽  
V.A. Makarov ◽  
K.S. Grigoriev ◽  
M.S. Yatskevitch ◽  
O.G. Kosareva
Keyword(s):  
Laser Beam ◽  
The Self ◽  
Kerr Medium ◽  
Self Focusing ◽  
Elliptically Polarized

scholarly journals Генерация поверхностного потока жидкости в каналах капиллярными колебаниями и волнами

2022 ◽  
Vol 92 (2) ◽  
pp. 194
Author(s):  
В.А. Александров
Keyword(s):  
Water Surface ◽  
Surface Deformation ◽  
Liquid Surface ◽  
Capillary Wave ◽  
Surface Flow ◽  
Capillary Waves ◽  
Curved Surface ◽  
Excess Surface ◽  
Surface Liquid ◽  
Wave Momentum

The generation of a directed flow on the water surface in channels with sources and resonators of capillary oscillations is detected and investigated. The surface flow is caused by the movement of the liquid through the gaps between the resonators, as well as between the resonator and the channel walls, under a curved surface that is locally deformed by the sources of capillary vibrations, the transfer of energy of the locally curved surface of the liquid by capillary waves, and the transmission of wave momentum to the particles of the liquid surface in one direction. It is shown that capillary waves together with the energy transfer an excess surface, the flux density of which is equal to the flux of the surface deformation. Moving devices with a capillary-wave accelerator of the surface liquid flow are demonstrated.

Focusing of an Intense Relativistic Electron Beam by a Hollow Conical Laser Beam

1975 ◽  
Vol 30 (8) ◽  
pp. 976-980
Author(s):  
F. Winterberg
Keyword(s):  
Laser Beam ◽  
Relativistic Electron ◽  
Radiation Pressure ◽  
Relativistic Electron Beam ◽  
Laser Light ◽  
Electron Beams ◽  
The Self ◽  
Intense Laser ◽  
Power Laser ◽  
Self Focusing

Abstract Estimates suggest that the nonlinear transverse radiation pressure produced within a plasma by a convergent annular high power laser beam may lead to the focusing of an intense relativistic electron down to a radius of ~10-4 cm. The transverse radiation pressure results from the dielectric property of a plasma in conjunction with the phenomena of the self-focusing of intense laser light. The tightly focused electron beams would make possible the release of thermonuclear energy by micro-explosions.

LASER BEAM SELF-FOCUSING IN PHOTOREFRACTIVE MATERIALS: OPTICAL LIMITING APPLICATION

2000 ◽  
Vol 09 (04) ◽  
pp. 441-450 ◽  
Author(s):  
D. WOLFERSBERGER ◽  
N. FRESSENGEAS ◽  
J. MAUFOY ◽  
G. KUGEL
Keyword(s):  
Laser Radiation ◽  
Laser Beam ◽  
Beam Energy ◽  
Optical Limiting ◽  
Low Energy ◽  
The Self ◽  
Self Focusing ◽  
Photorefractive Materials ◽  
Pulsed Regime ◽  
Different Time Scales

This paper presents a way to achieve optical limiting using the self-focusing of a laser beam in a photorefractive medium. In this view, the protection is not based on the absorption of the beam energy in the limiting system but on a global defocusing of the light in the optical system. We have studied experimentally and theoretically the self-focusing of a single laser beam in electrically biased Bi 12 TiO 20 from the continuous to the pulsed regime. We show that photorefractive materials are, for given conditions, efficient against laser radiation on these two different time scales at a low energy level (nJ).

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