Inwardly rotating spiral waves in a reaction-diffusion system

Almost 30 years have passed since the discovery of concentric (target) and spiral waves in the spatially extended Belousov-Zhabotinsky (BZ) reaction. Since then, rotating spirals and target waves have been observed in a varie ty of physical, chemical, and biological reaction-diffusion systems. AR of these waves propagate out from the spiral center or pacemaker. We report ob servations of inwardly rotating spirals found in the BZ system dispersed in water droplets of a water-in-oil microemulsion. These "antispirals" were a lso generated in computer simulations.