PDE seminar: A mechanism of spiral formation in heterogeneous discretized excitable media

2012-11-19 16:30 - 2012-11-19 17:30
Faculty of Science Building #3, Room 309
Shu-ichi Kinoshita (Meiji University)
Spontaneous spiral formation in heterogeneous excitable
media is observed in a wide variety of natural systems,
ranging from heart disease such as Ventricular Fibrillation
to chemical systems such as the Belousov-Zhabotinsky
(BZ) reaction. This system shows three type of behavior, as
the coupling in a heterogeneous excitable medium is reduced:
(a) plane waves propagate without breaking up, (b)
plane waves break up into spiral waves, and (c) plane
waves block. In this study, we focus on the origin of spiral
wave by three kinds of methods: photosensitive BZ reaction,
the discretized FitzHugh-Nagumo model (D-FHN) and
the simplified cellular automaton model (CA). Our results
show that unidirectional paths play very important role
for a spiral formation in heterogeneous excitable media.