On the possibility of metamaterial properties in spin plasmas

TL;DR

This paper explores how incorporating electron spin into plasma fluid theory can lead to metamaterial-like properties, including negative magnetic permeability and associated instabilities, opening new avenues for plasma manipulation.

Contribution

It extends plasma fluid theory to include electron spin effects, revealing conditions under which spin plasmas exhibit metamaterial properties and potential instabilities.

Findings

Spin effects alter magnetic permeability in plasmas.

Negative magnetic permeability can be achieved by magnetic field orientation.

Spin plasma can act as a metamaterial in specific frequency ranges.

Abstract

The fluid theory of plasmas is extended to include the properties of electron spin. The linear theory of waves in a magnetized plasma is presented, and it is shown that the spin effects causes a change of the magnetic permeability. Furthemore, by changing the direction of the external magnetic field, the magnetic permability may become negative. This leads to instabilities in the long wavelength regimes. If these can be controlled, however, the spin plasma becomes a metamaterial for a broad range of frequencies, i.e. above the ion cyclotron frequency but below the electron cyclotron frequency. The consequences of our results are discussed.