Ponderomotive force due to the intrinsic spin for electrostatic waves in a magnetized plasma

TL;DR

This paper investigates how electron spin influences the ponderomotive force in magnetized plasmas, deriving an analytical expression and comparing classical and spin contributions for different electrostatic wave modes.

Contribution

It introduces a quantum kinetic model with spin-orbit correction to analytically evaluate the spin's effect on the ponderomotive force in plasma waves.

Findings

Spin can dominate the ponderomotive force in Langmuir waves under certain conditions.

Classical contributions may dominate in spin-resonance wave modes.

The relative importance of spin versus classical effects depends on plasma parameters.

Abstract

We study the contribution from the electron spin to the ponderomotive force, using a quantum kinetic model including the spin-orbit correction. Specifically, we derive an analytical expression for the ponderomotive force, applicable for electrostatic waves propagating parallel to an external magnetic field. To evaluate the expression, we focus on the case of Langmuir waves and on the case of the spin-resonance wave mode, where the classical and spin contributions to the ponderomotive force are compared. Somewhat surprisingly, dependent on the parameter regime, we find that the spin contribution to the ponderomotive force may dominate for the Langmuir wave, whereas the classical contribution can dominate for the spin resonance mode. Naturally, this does not prevent the opposite case from being the more common one.