Self-focusing and Self-phase Modulation of Quadruple Gaussian (QG) Laser Beams in Thermal Quantum Plasma (TQP) with Axial Density Ramp
N. Gupta and S. Akshaya
A theoretical study on the self-action effects of intense laser beams propagating through thermal quantum plasma (TQP) is presented herein. Particularly, the phenomena associated with the nonlinear refraction of the laser beam have been investigated in detail. In order to see the effect of uniformity of the illumination over the beam phase fronts on its propagation characteristics the irradiance profile of the beam has been modelled by quadruple Gaussian (QG) profile. Following variational theory approach the nonlinear partial differential equation (PDE) for the beam envelope has been reduced to a set of coupled ordinary differential equations (ODEs) for the evolution of beam width and longitudinal phase. The equations so obtained have been solved numerically to envision the effect of laser as well as medium parameters on the propagation characteristics of the laser beam.
Keywords: Laser beam, plasma, thermal quantum plasma (TQP), quadruple Gaussian (QG), numerical solution, partial differential equation (PDE), ordinary differential equations (ODEs)