# Kinetic plasma waves carrying orbital angular momentum

## TL;DR

This paper investigates how Langmuir plasma waves with orbital angular momentum are affected by kinetic effects, revealing mode coupling, modified dispersion, damping, and magnetic field generation through theoretical analysis and simulations.

## Contribution

It introduces a kinetic theory framework for plasma waves with orbital angular momentum, highlighting mode coupling and magnetic field generation not previously detailed.

## Key findings

- Kinetic effects cause coupling of Laguerre-Gaussian modes.
- Propagation leads to generation of axial and azimuthal magnetic fields.
- Wave dispersion and damping are modified by higher-order electron distribution moments.

## Abstract

The structure of Langmuir plasma waves carrying a finite angular orbital momentum is revised in the paraxial optics approximation. It is shown that the kinetic effects related to higher-order momenta of the electron distribution function lead to coupling of Laguerre-Gaussian modes and result in modification of the wave dispersion and damping. The theoretical analysis is compared to the three-dimensional particle-in-cell numerical simulations for a mode with orbital momentum l = 2. It is demonstrated that propagation of such a plasma wave is accompanied with generation of quasi-static axial and azimuthal magnetic fields which are consequence of the longitudinal and orbital momentum transported with the wave.