S P Mishra
Abstract:
An analytical framework has been established to explore the excitation of electrostatic lower hybrid waves through the counterpropagation of two distinct laser beam profiles in a collisional plasma that is subjected to a static magnetic field. The interference of the two laser beams results in a nonlinear ponderomotive effect on the plasma electrons, which may effectively couple with the pre-existing electrostatic lower hybrid wave. The excitation of the lower hybrid wave is significantly enhanced when the interference of the two different laser beam profiles is aligned with the electrostatic lower hybrid wave. In cases where the beatings of the two laser beams possess a finite y-extent, the electrostatic lower hybrid wave exhibits an effective y-component wave number and a component of group velocity that aligns with the static magnetic field, leading to convective losses. The unique power profile shape of the electrostatic lower hybrid wave indicates that it can be further excited by variations in parameters such as the laser beam decentered parameter, beam width parameter, Hermite polynomial mode index, laser beam transverse propagation distance, electron-neutral collision frequency, and electron cyclotron frequency. This theoretical framework for the excitation of electrostatic lower hybrid waves may be applicable in processes such as electron heating and laser high harmonic generation.
