Azimuthally polarized terahertz radiation generation using a radially polarized laser pulse in magnetized plasma

An analytical formulation of a radially polarized laser pulse propagating in a homogeneous, magnetized plasma is presented using Lorentz force, continuity, and Maxwell's equations. The perturbation technique and quasi-static approximation have been used to study the generated fields in a nonlinear regime. The generated slow, oscillating, transverse electric and magnetic fields (Eθ and Br) having equal amplitude constitute a radiation field having frequency in the terahertz (THz) range. Particle-in-cell simulation code Fourier-Bessel particle-in-cell is used to validate analytical findings. Simulation studies also show that the generated THz radiation field propagates beyond the plasma boundary, indicating coherent electromagnetic radiation emission. Furthermore, the field amplitude scales nonlinearly with plasma density and increases linearly with external magnetic field strength, highlighting the role of these parameters in controlling radiation amplitude.