Effect of relativistic self-focusing on plasma wave excitation by a hollow Gaussian beam

A paraxial-like approach has been invoked to understand the nature of propagation of a hollow Gaussian beam (HGB) propagating in plasma under the influence of relativistic non-linearity. In this approach, the parameters are expanded in terms of the radial distance from the maximum of irradiance rather than that from the axis. This paper investigates the excitation of plasma wave in a hot collision less plasma by HGB. On account of the × force, a plasma wave at 2ω0 (here, ω0 is the pump laser frequency) is generated. The solution of the HGB has been obtained within the paraxial ray approximation. Filamentary structures of the laser beam are observed due to relativistic non-linearity.

Stable Stationary Solitons of the One-Dimensional Modified Complex Ginzburg-Landau Equation

We report on the existence of a new family of stable stationary solitons of the one-dimensional modified complex Ginzburg-Landau equation. By applying the paraxial ray approximation, we obtain the relation between the width and the peak amplitude of the stationary soliton in terms of the model parameters. We verify the analytical results by direct numerical simulations and show the stability of the stationary solitons.

Relativistic self-focusing of transmitted laser radiation in plasmas

This paper presents an analysis of relativistic self-focusing of a Gaussian laser beam incident normally on a plane interface of a linear medium and a nonlinear, nonabsorbing plasma with an intensity dependent dielectric constant. Considering the nonlinearity to arise from the relativistic variation of mass and the Lorentz force on electrons. Following Wentzel–Kramers–Brillouin (WKB) and paraxial ray approximation the phenomenon of relativistic self-focusing of the transmitted laser radiation has been analyzed for the arbitrary magnitude of nonlinearity. Change in the intensity distribution along the wavefront of the Gaussian beam, due to refraction at the interface has also been taken into account. The variation of beamwidth parameter with distance of propagation, self trapping condition and critical power has been evaluated. Numerical estimates for typical parameters of laser plasma interaction process indicate the refraction at the interface to have a significant effect on self-focusing.