Twisted terahertz radiation generation using a Laguerre–Gaussian laser pulse propagating in axially magnetized plasma

We present an analytical and simulation study of twisted terahertz (THz) radiation generation through the propagation of a circularly polarized Laguerre–Gaussian laser pulse in homogeneous plasma embedded in an axial magnetic field. The analytical formulation is based on the perturbation technique and quasi-static approximation. Longitudinal and transverse wakefields generated via laser–plasma interactions are evaluated using the Lorentz force and Maxwell's equations in the mildly nonlinear regime. It is observed that two linearly polarized twisted THz radiation beams are generated in mutually perpendicular planes. The superposition of these two beams results in a single linearly polarized twisted THz radiation beam with modified amplitude and polarization direction. Three-dimensional particle-in-cell simulations are performed for this configuration using the Fourier-Bessel particle-in-cell code. A graphical comparison of the amplitude of the resultant THz beam, obtained from both analytical and simulation studies, is presented.