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

1975 ◽  
Vol 30 (8) ◽  
pp. 976-980
Author(s):  
F. Winterberg

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.

2014 ◽  
Vol 32 (3) ◽  
pp. 477-486 ◽  
Author(s):  
Alexandru Popa

AbstractWe prove that the radiation damping force and the rate of change of the damping energy, in the Landau-Lifshitz forms, in interactions between very intense laser beams and relativistic electron beams, are periodic functions of only one variable, that is the phase of the electromagnetic field. The property is proved without using any approximation, in the most general case, when the degree of polarization of the electromagnetic field, the initial phase of the incident field and the initial energy of the electron have arbitrary values. This property leads to a strong simplification of the calculation of the radiation reaction parameters and of their dependence on the initial electron energy and angular frequency of the laser beam. Our analysis is performed in the proper inertial system of the electron. The radiation reaction is significant for laser beam intensities of the order 1022 W/cm2, and for electron energy greater than 1 GeV. The calculations reveal limitations of the method of generating hard radiations by interactions between laser beams and relativistic electron beams.


2014 ◽  
Vol 32 (2) ◽  
pp. 321-330 ◽  
Author(s):  
N. Sepehri Javan ◽  
M. Hosseinpour Azad

AbstractSelf-focusing of an intense circularly-polarized laser beam in a hot electron-positron-ion magneto-plasma is studied. Using a relativistic fluid model, nonlinear equation describing laser-plasma interaction in the quasi-neutral approximation is derived. Expanding nonlinear current density in terms of normalized vector potential and saving only the parabolic terms, we investigated the self-focusing phenomenon for right- and left-hand circularly polarized laser beams. The evolution of laser beam spot size with Gaussian profile is considered. Effects of the external magnetic field, fraction of electron-positron pairs, and also the kind of polarization on the self-focusing property are studied. It is shown that a mixture of electron-positron pairs to the ion-electron plasma modifies the behavior of plasma with respect to the external magnetic field.


1999 ◽  
Vol 62 (4) ◽  
pp. 389-396 ◽  
Author(s):  
M. V. ASTHANA ◽  
A. GIULIETTI ◽  
DINESH VARSHNEY ◽  
M. S. SODHA

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.


1986 ◽  
Vol 64 (9) ◽  
pp. 1341-1344 ◽  
Author(s):  
J. Hartikainen ◽  
J. Jaarinen ◽  
M. Luukkala

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.


2021 ◽  
Author(s):  
Gunjan Purohit ◽  
Bineet Gaur ◽  
Pradeep Kothiyal ◽  
Amita Raizada

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.


1999 ◽  
Vol 27 (5) ◽  
pp. 1501-1509 ◽  
Author(s):  
C. Vermare ◽  
J.T. Donohue ◽  
J. Labrouche ◽  
P. Le Taillandier de Gabory ◽  
D. Villate

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