Nonlinear stability of source defects in oscillatory media

In this paper, we prove the nonlinear stability under localized perturbations of spectrally stable time-periodic source defects of reaction-diffusion systems. Consisting of a core that emits periodic wave trains to each side, source defects are important as organizing centers of more complicated flows. Our analysis uses spatial dynamics combined with an instantaneous phase-tracking technique to obtain detailed pointwise estimates describing perturbations to lowest order as a phase-shift radiating outward at a linear rate plus a pair of localized approximately Gaussian excitations along the phase-shift boundaries; we show that in the wake of these outgoing waves the perturbed solution converges time-exponentially to a space-time translate of the original source pattern.https://arxiv.org/abs/1802.07676First author draf

Noisy patterns: Bridging the gap between stochastics and dynamics

In this thesis, we study travelling waves in stochastic reaction-diffusion equations. We extend techniques from the deterministic theory for travelling waves to apply to the stochastic version, which allows us to compute the stochastic wave speed and shape, and draw conclusions on the stability of the wave.Analysis and Stochastic