Nonlinear evolution of localized structures and turbulent magnetic field amplification by extraordinary laser beam in laser produced plasmas

Abstract

In the present investigation, the nonlinear coupling of waves is evaluated to understand the turbulent magnetic field in the laser-produced plasma. The model equations are set up for the extraordinary (x-mode) laser and upper hybrid oscillations, incorporating the relativistic electron mass variation and the nonlinear ponderomotive force. The upper hybrid oscillations are excited due to the nonlinear ponderomotive force exerted by the x-mode laser. The nonlinear coupled system of x-mode laser and the upper hybrid oscillations were simulated numerically. Simulation results depict the evolution of localized structures with time. The ensemble-averaged turbulent power spectrum is obtained through numerical simulations. Furthermore, the frequency spectra associated with upper hybrid oscillation lie in the terahertz (THz) frequency range. A semi-analytical approach in the paraxial approximation has been studied to get a better perspective of the field localization process. Such studies of nonlinear wave-wave interaction are crucial to understand the turbulent magnetic field generation relating to various laboratory and astrophysical scenarios.