ANISOTROPY AND SPIRAL ORGANIZING CENTERS IN PATTERNED EXCITABLE MEDIA

Chemical wave behavior in a patterned Belousov-Zhabotinsky system prep ared by printing the catalyst of the reaction on membranes with an ink jet printer is described. Cellular inhomogeneities give rise to globa l anisotropy in wave propagation, with specific local patterns resulti ng in hexagonal, diamond, and pentagonal geometries. Spiral wave sourc es appear spontaneously and serve as organizing centers of the surroun ding wave activity. The experimental methodology offers flexibility fo r studies of excitable media with made-to-order spatial inhomogeneitie s.