  We study the dynamics of a reaction-diffusion system composed of two mutually
coupled excitable fibers. We focus on the situation in which dynamical
properties of the two fibers are not identical because of the parameter
difference between the fibers. Using the spatially one-dimensional
FitzHugh-Nagumo equations as a model of a single excitable fiber, we show that
the system exhibits a rich variety of dynamical behavior, including
soliton-like collision between two pulses, recombination of a solitary pulse
and synchronized pulses, and overtaking of a slow-moving solitary pulse by
fast-moving synchronized pulses.
