Self-focusing of a Hermite-cosh Gaussian laser beam in a magnetoplasma with ramp density profile

Abstract

The early and strong self-focusing of a Hermite-cosh-Gaussian laser beam in magnetoplasma in the presence of density ramp has been observed. Focusing and de-focusing nature of the Hermite-cosh-Gaussian laser beam with decentered parameter and magnetic field has been studied, and strong self-focusing is reported. It is investigated that decentered parameter "b" plays a significant role for the self-focusing of the laser beam and is very sensitive as in case of extraordinary mode. For mode indices, m = 0, 1, 2,andb = 4.00, 3.14,and2.05, strong self-focusing is observed. Similarly in case of ordinary mode, for m = 0, 1, 2andb = 4.00, 3.14, 2.049, respectively, strong self-focusing is reported. Further, it is seen that extraordinary mode is more prominent toward self-focusing rather than ordinary mode of propagation. For mode indices m = 0, 1,and2, diffraction term becomes more dominant over nonlinear term for decentered parameter b=0. For selective higher values of decentered parameter in case of mode indices m=0, 1,and2, self-focusing effect becomes strong for extraordinary mode. Also increase in the value of magnetic field enhances the self-focusing ability of the laser beam, which is very useful in the applications like the generation of inertial fusion energy driven by lasers, laser driven accelerators, and x-ray lasers.