Abstract

In many oscillatory or excitable systems, dynamical patterns emerge which are stationary or periodic in a moving frame of reference. Examples include traveling waves or spiral waves in chemical systems or cardiac tissue. We present a unified theoretical framework for the drift of such patterns under small external perturbations, in terms of overlap integrals between the perturbation and the adjoint critical eigenfunctions of the linearized operator (i.e., response functions). For spiral waves, the finite radius of the spiral tip trajectory and spiral wave meander are taken into account. Different coordinate systems can be chosen, depending on whether one wants to predict the motion of the spiral-wave tip, the time-averaged tip path, or the center of the meander flower. The framework is applied to analyze the drift of a meandering spiral wave in a constant external field in different regimes.

Highlights

  • Spiral waves are remarkable self-sustained patterns which arise in various extended systems, including oscillating chemical reactions [1], catalytic oxidation [2], and biological systems

  • VII we reinterpret our approach in terms of the geometry of the phase space of the reaction-diffusion system considered as a dynamical system. This part is optional, but we found it useful to include as few works make the connection between the physics style of description and the more abstract dynamical systems viewpoint

  • We show how the dynamics can be averaged over rotation and temporal phases in order to find a simpler, manageable equation of motion

Read more

Summary

INTRODUCTION

Spiral waves are remarkable self-sustained patterns which arise in various extended systems, including oscillating chemical reactions [1], catalytic oxidation [2], and biological systems. This picture was put on constructive footing in [51,52,53,54], using a skew-product representation of the reaction-diffusion system exploiting its symmetry with respect to Euclidean motions of the plane These works described the equivariant Hopf bifurcation (i.e., the regime close to the transition to meander), while many chemical and cardiac models show a qualitatively different tip trajectory, i.e., a zigzagged starlike path known as the linear core case. A significant part of this paper will be dealing with introducing different coordinate systems that are suitable to capture the drift dynamics of solutions to the RDE (1) because, depending on which definition of filament one adopts, one can obtain simple or complex laws of motion These laws can be further simplified if one averages in time over rotation cycles of the spiral or scroll waves [36].

SYMMETRY CONSIDERATIONS
General framework
Symmetry breaking
Rigidly translating waves
Periodically modulated waves
Constant-speed comoving frame
SPIRAL WAVES
Center frame
Tip frame
Rigidly rotating spiral waves
Meandering spiral waves
Definition of the angle β between petals
Minimally rotating finite-core frame
Corotating finite-core frame
Comparison with the classical theory of meander
Resonant meander
Minimally rotating comoving frame
General case
Right-hand zero modes
Adjoint problem Let us associate with Lthe operator
Instant orthogonality of left and right critical modes
SPATIOTEMPORAL DRIFT OF PATTERNS UNDER A SMALL PERTURBATION
GEOMETRIC INTERPRETATION
Phase-space orbits
Spatial vs spatiotemporal symmetries
Quotient space
Inertial manifold
Collective coordinates parametrize the inertial manifold
Tangent spaces
Effect of a small perturbation
Coordinate change in the tangent manifold
Motivation
Average drift of a circular core spiral
Phase locking of a meandering spiral under a constant external field
Regime close to phase locking
Average drift speed of a non-phase-locked meandering spiral
DISCUSSION
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call