Existence, Uniqueness and Classification of Plane Waves
Robert Milton
TL;DR
The paper analyzes plane waves in irreversible reaction-diffusion systems by recasting the problem as an autonomous dynamical system and employing a phase-space framework. It proves existence, uniqueness, and classification of plane waves for lentor values up to a critical threshold, and extends to cutoff reactions; the approach hinges on orbit contrast and breach cascades to compare interior orbits and ensure termination within a compact environment. While the results align with established literature, the authors emphasize a simple, analytic proof strategy that complements fixed-point and Leray-Schauder methods. The work provides a pedagogical, methodology-focused account that could inform analysis of related dynamical systems and supports practical extensions to cutoff-reaction models.
Abstract
Existence, uniqueness and classification is established for plane waves supported by an irreversible reaction which is a smooth function of local reactant and product concentrations (or prey and predator populations). Rudimentary analytic techniques are used to guarantee a unique plane wave at every wavespeed $V>V_*$ above some threshold. The result readily extends to cutoff reactions, which are zero below some threshold product concentration. These results are not novel, but the method of proof is.
