An introduction to spatial dispersion: revisiting the basic concepts

TL;DR

This paper clarifies the fundamental mechanisms behind spatial dispersion in wave propagation, emphasizing geometry, structure, and dynamics as key factors for understanding and naming spatially dispersive phenomena.

Contribution

It revisits and clarifies the basic concepts of spatial dispersion, proposing a clear framework based on geometry, structure, and dynamics for understanding these phenomena.

Findings

Identifies three mechanisms causing spatial dispersion: geometry, structure, and dynamics.

Proposes a standardized way to understand and name spatially dispersive phenomena.

Clarifies the role of spatial properties in wave propagation behavior.

Abstract

I describe three ways that the spatial properties of a wave propagation medium can cause dispersion, and propose that they should form the basics for correctly understanding and naming phenomena described as "spatial dispersion". In particular, I emphasise the specific spatial properties which generate the resulting dispersive -- i.e. spatially dispersive -- behaviour. The mechanisms are geometry, structure, and dynamics.