Non-specular reflections in a macroscopic system with wave-particle duality: spiral waves in bounded media

TL;DR

This paper investigates how spiral waves in excitable media reflect off boundaries, revealing near-constant reflection angles and boundary interactions, using numerical simulations to explore different boundary types and spiral core sizes.

Contribution

It provides a detailed numerical study of spiral wave reflections from various boundaries, highlighting phenomena like near-constant reflection angles and boundary binding, extending previous theories.

Findings

Reflected angle varies little with incident angle for large ranges.

Large-core spirals can bind to boundaries.

Different boundary types influence reflection behavior.

Abstract

Spiral waves in excitable media possess both wave-like and particle-like properties. When resonantly forced (forced at the spiral rotation frequency) spiral cores travel along straight trajectories, but may reflect from medium boundaries. Here, numerical simulations are used to study reflections from two types of boundaries. The first is a no-flux boundary which waves cannot cross, while the second is a step change in the medium excitability which waves do cross. Both small-core and large-core spirals are investigated. The predominant feature in all cases is that the reflected angle varies very little with incident angle for large ranges of incident angles. Comparisons are made to the theory of Biktashev and Holden. Large-core spirals exhibit other phenomena such as binding to boundaries. The dynamics of multiple reflections is briefly considered.