Investigation of heavy ions diffusion under the influence of current-driven mechanism and compositional waves in plasma

TL;DR

This paper explores how electric currents and the Hall effect induce diffusion in plasma, leading to chemical inhomogeneities and the formation of element spots, along with the discovery of new compositional waves affecting plasma emission spectra.

Contribution

It introduces a novel current-driven diffusion mechanism in plasma and identifies a new type of compositional waves caused by impurity density oscillations.

Findings

Diffusion causes chemical inhomogeneities in plasma.

New compositional waves can propagate with frequencies determined by electric currents.

These waves can cause observable spectral line variations.

Abstract

We consider diffusion caused by a combined influence of the Hall effect and electric currents, and argue that such diffusion forms chemical inhomogeneities in plasma. The considered mechanism can be responsible for the formation of element spots in laboratory and astrophysical plasmas. Such current-driven diffusion can be accompanied by the propagation of a particular type of waves which have not been considered earlier. In these waves, the impurity number density oscillare alone and their frequency is determined by the electric currents and sort of impurity ions. These compositional waves exist if the magnetic pressure in plasma is much greater than the gas pressure. Such waves lead to local variations of chemical composition and, hence, can manifest themselves by variations of the emission in spectral lines.