Focusing of a dark hollow Gaussian electromagnetic beam in a magnetoplasma

Abstract

This paper presents an analysis and subsequent discussion of the self focusing of a dark hollow Gaussian electromagnetic beam (HGB) in a magnetoplasma, considering ponderomotive and collisional nonlinearities. A paraxial-like approach, in which the relevant parameters are expanded in terms of radial distance from the maximum of the irradiance rather than that from the axis, has been adopted to analyze the propagation of the HGB. The nature of self focusing is highlighted through the critical curves as a plot of dimensionless radius versus power of the beam. The effect of the magnetic field and the nature of the nonlinearity on self focusing of various order HGBs has also been explored.

Focusing of Dark Hollow Gaussian Electromagnetic Beams in a Plasma With Relativistic-Ponderomotive Regime

“…Further a modified theory [64] for propagation of TEM 01 mode of the beam, considering diffraction and the saturating nature of the non-linearity, has been developed. In a recent investigation Sodha et al [65,66] have presented a modified paraxial-like approach, similar to the one given by Akhmanov et al [3] and developed by Sodha et al [4,5], to analyze the propagation characteristics of a hollow Gaussian beam in the vicinity of its irradiance maximum in the plasma by taking note of the saturating character of the nonlinearities. However, all the three basic nonlinearities of the plasma (i.e., ponderomotive, collisional and relativistic) have been analyzed separately to a significant extent but their combined effect has not been discussed in the context of the HGB.…”

“…The present work is based on the modified approach followed by Sodha et al [65,66] and represents the extension of the theory to plasmas in which the relativistic and ponderomotive nonlinearities are operating simultaneously. Thus this investigation is inclusive of the following considerations:…”

The Fractional Fourier Transform of Hypergeometric-Gauss Beams Through the Hard Edge Aperture

“…Sodha et al have studied the transmission characteristics of focusing and self-focused hollow beam in different dielectrics [6]. There have been lots of research on its extensive applications since Kotlyar et al proposed a new paraxial hypergeometric beam [7], and especially they obtained it by using another kind of solution of scalar Helmholtz equation, which has limited energy and can be produced in the experiments [8].…”

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

“…Beam self-focusing is strongly affected by the transverse distribution of beam irradiance (Sodha & Faisal, 2008;Sodha et al, 1976;Sodha et al, 1974). In a recent series of investigations, Sodha et al (2009aSodha et al ( , 2009b have presented a modified paraxial-like approach to analyze the propagation characteristics of a hollow Gaussian beam (HGB) in the vicinity of its irradiance maximum in the plasma by taking note of the saturating character of the nonlinearities (i.e., ponderomotive, collisional, and relativistic). In continuation of previous investigations (Sodha et al, 2009a(Sodha et al, , 2009b Misra and Mishra (2009) modeled the propagation of a hollow Gaussian electro-magnetic beam in a plasma, considering the combined effect of relativistic and ponderomotive nonlinearity.…”

“…In a recent series of investigations, Sodha et al (2009aSodha et al ( , 2009b have presented a modified paraxial-like approach to analyze the propagation characteristics of a hollow Gaussian beam (HGB) in the vicinity of its irradiance maximum in the plasma by taking note of the saturating character of the nonlinearities (i.e., ponderomotive, collisional, and relativistic). In continuation of previous investigations (Sodha et al, 2009a(Sodha et al, , 2009b Misra and Mishra (2009) modeled the propagation of a hollow Gaussian electro-magnetic beam in a plasma, considering the combined effect of relativistic and ponderomotive nonlinearity. It is shown that the critical curves and self focusing depend strongly on the order of the HGB; the propagation of the HGB follows the characteristic three regimes in the vicinity of the maximum irradiance.…”