A linear dispersion relation for the hybrid kinetic-ion/fluid-electron model of plasma physics

TL;DR

This paper derives a comprehensive dispersion relation for a hybrid plasma model combining kinetic ions and fluid electrons, enabling better analysis of wave phenomena in plasma physics.

Contribution

It provides the first general dispersion relation for this hybrid model, including effects like wave angle, anisotropy, and generalized Ohm's law terms.

Findings

Developed a numerical solver for the dispersion relation.

Benchmarked wave physics against full Vlasov-Maxwell solutions.

Enhanced understanding of wave behavior in hybrid plasma models.

Abstract

A dispersion relation for a commonly used hybrid model of plasma physics is developed, which combines fully kinetic ions and a massless-electron fluid description. Although this model and variations of it have been used to describe plasma phenomena for about 40 years, to date there exists no general dispersion relation to describe the linear wave physics contained in the model. Previous efforts along these lines are extended here to retain arbitrary wave propagation angles, temperature anisotropy effects, as well as additional terms in the generalized Ohm's law which determines the electric field. A numerical solver for the dispersion relation is developed, and linear wave physics is benchmarked against solutions of a full Vlasov-Maxwell dispersion relation solver. This work opens the door to a more accurate interpretation of existing and future wave and turbulence simulations using this type of hybrid model.