Self-focusing of a cosh-Gaussian laser beam in magnetized plasma under relativistic-ponderomotive regime

The combined effect of relativistic and ponderomotive nonlinearities on the self-focusing of an intense cosh-Gaussian laser beam (CGLB) in magnetized plasma have been investigated. Higher-order paraxial-ray approximation has been used to set up the self-focusing equations, where higher-order terms in the expansion of the dielectric function and the eikonal are taken into account. The effects of various lasers and plasma parameters viz. laser intensity (a(0)), decentred parameter (b), and magnetic field (omega(c)) on the self-focusing of CGLB have been explored. The results are compared with the Gaussian profile of laser beams and relativistic nonlinearity. Self-focusing can be enhanced by optimizing and selecting the appropriate laser-plasma parameters. It is observed that the focusing of CGLB is fast in a nonparaxial region in comparison with that of a Gaussian laser beam and in a paraxial region in magnetized plasma. In addition, strong self-focusing of CGLB is observed at higher values of a(0), b, and omega(c). Numerical results show that CGLB can produce ultrahigh laser irradiance over distances much greater than the Rayleigh length, which can be used for various applications.