A quasi-local inhomogeneous dielectric tensor for arbitrary distribution functions

TL;DR

This paper derives a new quasi-local inhomogeneous dielectric tensor for plasmas with arbitrary distribution functions, improving accuracy in modeling wave propagation and damping in inhomogeneous plasma environments.

Contribution

It introduces a novel correction to the plasma dielectric tensor for arbitrary distributions, with a new integration technique applicable in various plasma wave problems.

Findings

Inhomogeneous wave damping does not affect the linear damping condition of lower-hybrid waves.

Damping and propagation are largely unaffected in non-Maxwellian plasmas unless waves have very large phase velocities.

The new dielectric tensor provides greater accuracy than existing formulas for inhomogeneous plasmas.

Abstract

Treatments of plasma waves usually assume homogeneity, but the parallel gradients ubiquitous in plasmas can modify wave propagation and absorption. We derive a quasilocal inhomogeneous correction to the plasma dielectric for arbitrary distributions by expanding the phase correlation integral and develop a novel integration technique that allows our correction to be applied in many situations and has greater accuracy than other inhomogeneous dielectric formulas found in the literature. We apply this dielectric tensor to the lower-hybrid current drive problem and demonstrate that inhomogeneous wave damping does not affect the lower-hybrid wave's linear damping condition, and in the non-Maxwellian problem damping and propagation should remain unchanged except in the case of waves with very large phase velocities.