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Title: Generation of vortex rings by nonstationary laser wake field

Abstract

A new concept of generating quasistatic magnetic fields, vortex rings, and electron jets in an isotropic homogeneous plasma is presented. The propagation of plasma waves, generated by a relativistically intense short pulse laser, is investigated by using the kinetic model and a novel nonpotential, time-dependent ponderomotive force is derived by obtaining a hydrodynamic equation of motion. This force can in turn generate quasistatic magnetic fields, vortex rings, and electron jets. It is also shown that the vortex rings can become a means for accelerating electrons, which are initially in equilibrium. The conservation of canonical momentum circulation and the frozen-in condition for the vorticity is discussed. The excitation of the vortex waves by the modulation of the amplitude of the plasma waves is considered. These vortex waves, which generate a lower hybrid mode propagating across the generated magnetic field, are also investigated.

Authors:
; ;  [1];  [2];  [2]
  1. Department of Physics, Tbilisi State University, Chavchavadze 3 (Georgia)
  2. (Pakistan)
Publication Date:
OSTI Identifier:
20782438
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 13; Journal Issue: 1; Other Information: DOI: 10.1063/1.2158694; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AMPLITUDES; ELECTRONS; EQUATIONS OF MOTION; EXCITATION; HOMOGENEOUS PLASMA; LASER RADIATION; LASERS; LIGHT TRANSMISSION; LOWER HYBRID CURRENT DRIVE; LOWER HYBRID HEATING; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; PLASMA INSTABILITY; PLASMA JETS; PLASMA WAVES; PONDEROMOTIVE FORCE; PULSES; RELATIVISTIC PLASMA; TIME DEPENDENCE; VORTICES

Citation Formats

Tsintsadze, N.L., Murtaza, G., Shah, H.A., National Centre for Mathematics, G.C. University, Lahore 54000, and Department of Physics, G.C. University, Lahore 54000. Generation of vortex rings by nonstationary laser wake field. United States: N. p., 2006. Web. doi:10.1063/1.2158694.
Tsintsadze, N.L., Murtaza, G., Shah, H.A., National Centre for Mathematics, G.C. University, Lahore 54000, & Department of Physics, G.C. University, Lahore 54000. Generation of vortex rings by nonstationary laser wake field. United States. doi:10.1063/1.2158694.
Tsintsadze, N.L., Murtaza, G., Shah, H.A., National Centre for Mathematics, G.C. University, Lahore 54000, and Department of Physics, G.C. University, Lahore 54000. Sun . "Generation of vortex rings by nonstationary laser wake field". United States. doi:10.1063/1.2158694.
@article{osti_20782438,
title = {Generation of vortex rings by nonstationary laser wake field},
author = {Tsintsadze, N.L. and Murtaza, G. and Shah, H.A. and National Centre for Mathematics, G.C. University, Lahore 54000 and Department of Physics, G.C. University, Lahore 54000},
abstractNote = {A new concept of generating quasistatic magnetic fields, vortex rings, and electron jets in an isotropic homogeneous plasma is presented. The propagation of plasma waves, generated by a relativistically intense short pulse laser, is investigated by using the kinetic model and a novel nonpotential, time-dependent ponderomotive force is derived by obtaining a hydrodynamic equation of motion. This force can in turn generate quasistatic magnetic fields, vortex rings, and electron jets. It is also shown that the vortex rings can become a means for accelerating electrons, which are initially in equilibrium. The conservation of canonical momentum circulation and the frozen-in condition for the vorticity is discussed. The excitation of the vortex waves by the modulation of the amplitude of the plasma waves is considered. These vortex waves, which generate a lower hybrid mode propagating across the generated magnetic field, are also investigated.},
doi = {10.1063/1.2158694},
journal = {Physics of Plasmas},
number = 1,
volume = 13,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
  • The results of a two-dimensional particle-in-cell simulation and of an analytical description of the propagation in an underdense plasma of a short, relativistically intense, laser pulse are presented. Self-focusing is proven in an ultrarelativistic regime for moderately long pulses. Pulses shorter than the plasma wavelength, but wider than it, excite a wake wave with a regular electric field. The electron density in the wake has a horseshoe'' shape and focuses a long pulse locally. The excitation of stimulated Raman backward scattering is observed.
  • The generation of nonlinear plasma wake fields by an intense, short laser pulse and the relativistic optical guiding of intense laser pulses in plasmas are studied with a nonlinear, self-consistent model of laser--plasma interactions. Nonlinear steepening and period lengthening of the plasma waves are observed, and expressions are obtained for various nonlinear wake-field quantities. Relativistic focusing with the self-consistent plasma response shows that laser pulse fronts and laser pulses shorter than a plasma wavelength, 2{pi}{ital c}/{omega}{sub {ital p}}, are not relativistically guided and will continuously erode due to diffraction.
  • Magnetic field generation in the plasma wake of a relativisticly intense short pulse is studied, both analytically and by PIC-code simulation. We show that the magnetic field scales like (m{omega}{sub p}c/e)dI{sub L}/dr{sub perpendicular} in this case, different from (m{omega}{sub p}c/e)dI{sub L}{sup 2}/dr{sub perpendicular} for the low intensity case. The magnetic field profiles are calculated both for {beta}=1 and {beta}<1, which are found to be different in these two cases; here {beta} is the normalized phase velocity of the wake plasma wave.
  • One-dimensional nonlinear analysis of wake-field generation and electron bunch acceleration by a chirped laser pulse were investigated numerically. It was found that the optimum linear chirp parameter leads to the wake-field amplitude increase by one order of magnitude and accordingly the acceleration gradient. In our external injection scheme, electrons were accelerated using the initial energy of 100 KeV (gamma{sub in}=1.2). When the pulse passes through the electron bunch most part of the electrons trapped in the first cycle of the laser wake-field and accelerate to about 1 GeV in 1.8 mm. We concluded that the expensive electron preacceleration mechanism couldmore » be omitted in a laser-aided electron acceleration scheme.« less
  • An ultrashort laser pulse propagating in plasma can excite a nonlinear plasma wake field which can accelerate charged particles up to GeV energies within a compact space compared to the conventional accelerator devices. In this paper, the effect of different kinds of nonlinear chirped Gaussian laser pulse on wake field generation is investigated. The numerical analysis of our results depicts that the excitation of plasma wave with large and highly amplitude can be accomplished by nonlinear chirped pulses. The maximum amplitude of excited wake in nonlinear chirped pulse is approximately three times more than that of linear chirped pulse. Inmore » order to achieve high wake field generation, chirp parameters and functions should be set to optimal values.« less