Semiclassical relativistic fluid theory for ion-acoustic waves carrying orbital angular momentum in dense plasmas

In this investigation, we study the propagation characteristics of low-frequency ion-acoustic waves carrying finite orbital angular momentum (OAM) in a uniform, dense plasma consisting of inertialess, relativistic, degenerate electrons and classical fluid ions. The model equations yield a linear paraxial equation that describes the ion density perturbations. For such a paraxial problem, we evaluate the Laguerre–Gaussian (LG) beam solution. Using the paraxial approximation, the electrostatic potential and the consequent components of the electric field are determined. The LG-based solution displays helical-structured electric field lines, unlike the straight lines typical of plane wave solutions. Moreover, the OAM equation is derived in a relativistic degenerate plasma through the energy flux density linked with LG phonons. In the context of numerical analysis, we examine how the physical parameters characteristic of dense astrophysical systems, such as white dwarfs, modify the resulting potential profiles. In particular, it is shown how the LG potential is drastically reshaped with relativistic degeneracy parameter. The present study provides novel pathways for momentum and energy transport under extreme plasma conditions.