Study of Variation of Nonlinear Current in Plasma for Terahertz Radiation Generation

The Terahertz radiation generation through laser plasma interactions has attracted significant attention due to its wide range of applications in the field of spectroscopy, imaging, communications and medical. This work explores the variation of nonlinear current in the plasma which is the essential driver for Terahertz radiation generation. When intense laser pulses interact with plasma, a nonlinear ponderomotive force is generated, which leads to oscillations of plasma electrons. The oscillating electrons generate a nonlinear current, and their oscillation frequency causes the emission of Terahertz radiation. These nonlinear currents play a crucial role in exciting low-frequency electromagnetic waves in the THz regime. We analyze how the nonlinear current varies with key plasma parameters, including laser intensity, plasma density, magnetic field, and beam width. Theoretical modeling and numerical simulations demonstrate how optimizing these parameters enhances nonlinear current. Our results provide insights into controlling and optimizing nonlinear plasma currents for enhanced THz generation, offering promising advancements in plasma-based THz sources. This paper presents a theoretical model to describe the variation of nonlinear current as a function of these parameters, and investigated how laser beating can modify the plasma response for terahertz radiation generation.