Generation of THz radiation by parametric coupling of Laser and Trivelpiece–Gould mode

A scheme to study powerful source of radiations at Terahertz band (THz) is proposed, wherein the high power extraordinary (X-mode) laser pump parametrically decays into Trivelpiece-Gould (TG) mode and Kinetic Alfven Wave (KAW) in a magnetized plasma system. In this process, the nonlinear coupling between X-mode laser (ω₀) and TG mode produces KAW with frequency in terahertz range (THz). The X-mode laser beam exerts a ponderomotive force on the electrons, and imparts a nonlinear oscillatory velocity at beat frequency. A strong transient current is generated by the nonlinear coupling of laser velocity and TG density perturbation. The requisite phase matching condition is shown by modeling the parallelogram. High dependency upon the applied transverse magnetic field is exhibited by the efficiency, power, beam quality, and the tunability of the present scheme. At the laser intensity of 10¹⁶ W/cm² and magnetic field of 30 MG, the evaluated power flux, P_THz comes out at the Terawatt level. With the optimization of various plasma parameters, the power conversion efficiency ~ is achieved