TOWARDS A NORMAL-FORM FOR SPIRAL WAVES

In this article we briefly present an approach based on the symmetry-b reaking of the Hopf Normal Form in an attempt to build up a dynamical equation which describes the formation of spiral waves in both oscilla ting and excitable systems. To the lowest order, two new parameters, w ith simple geometrical and dynamical interpretation, result respective ly from amplitude and phase rotational symmetry-breaking. They allow u s to model the most important experimental observations, namely front and spiral formation and the transition to meandering.