Localized and Extended Patterns in Reactive Media

We study the dynamics of interacting localized structures in homogeneous reactive media. Equations of motion for solitary waves in excitable media and for vortices in oscillatory media are derived under the assumption of weak interactions. We show that excitable media with oscillatory recovery can support a multitude of stable, nonuniform spatial patterns and that phase field effects in oscillatory media may lead to the formation of bound vortex pairs. The implications of the latter result on the transition to turbulence in oscillatory media are discussed.