title: Selection mechanism for rotating patterns in weakly excitable media.
abstract: Two types of patterns rigidly rotating within a disk of a weakly excitable medium are studied using the free-boundary approach. The patterns are spots moving along the boundary of the disk and spiral waves rotating around the disk center. The study reveals a selection mechanism that uniquely determines the shape and the angular velocity of these patterns as a function of the medium excitability and the disk radius. These two types of patterns coexist below some critical parameter value, coincide at a bifurcation point, and do not exist above it. The same selection mechanism is applied to describe a limiting case of a spiral wave rotating in an unbounded medium.
authors.affiliation: Institut für Theoretische Physik, Technische Universität Berlin, D-10623 Berlin, Germany.
authors.forename: Vladimir S
authors.initials: VS
authors.lastname: Zykov