Ion-acoustic waves with orbital angular momentum in a partially degenerate plasma

In this paper, we investigate the properties of ion-acoustic waves (IAWs) with finite orbital angular momentum (OAM) modes in a collisionless, unmagnetized, and homogeneous non-relativistic plasma comprised of degenerate electron species and inertial ions. Utilizing a fluid model, we derive the linear paraxial equation for ion density perturbations, where the electric field is decomposed into cylindrical components to reveal a helical, non-planar wave structure. The electrostatic potential is expressed in a Laguerre–Gaussian (LG) profile and analyzed numerically. We calculate the angular momentum density, demonstrating linear dependence on the angular (quantum) mode number. Our results show that the angular mode number, radial mode number, degenerate electron density, beam waist, and azimuthal angle have a considerable effect on the LG potential in a non-relativistic partially degenerate plasma system. Specifically, we emphasize the impact of electron number density (typically that of semiconductor quantum well environments) on the profile of the LG-type electrostatic potential. This research provides new insights into the behavior of IAWs with OAM in partially degenerate plasmas, with potential implications for advanced plasma applications and technologies.