Generation of terahertz radiation via cosh‐Gaussian and top‐hat laser beams in a collisional magnetized plasma

Abstract

This paper presents a scheme to generate terahertz (THz) radiation by the beating of lasers in a rippled density collisional magnetized plasma. The laser beams exert a ponderomotive force on the electrons of plasma and impart them with oscillatory velocity at the different frequencies of lasers. The direction of the uniform static magnetic field makes an angle with respect to the propagation direction of laser beams; in this case, two-mode waves can propagate in plasma. We derive the general formulas for efficiency and THz field amplitude with arbitrary laser beam profiles. The efficiency of the emitted radiations is found to be sensitive to laser profiles, the angle between laser beams and static magnetic field, collision frequency, and magnetic field strength. A comparison between the generated THz radiation by top-hat and cosh-Gaussian laser beams reveals, at the same conditions, that the generated THz radiation by top-hat laser beams produces a stronger ponderomotive force and a higher efficiency. KEYWORDScosh-Gaussian beam, terahertz generation, top-hat beam, uniform magnetic field 1