Complex dynamics of a spiral tip in the presence of an extrinsic local modulation
With a generic model excitable system, we have investigated the spatio-temporal dynamics of a spiral tip in the presence of an extrinsic localized periodic modulation. The tip of a modulated spiral does exhibit a variety of different trajectories depending on the strength and the frequency of the modulation. Its motion can be quasiperiodic on a 2-torus, quasiperiodic or mode locked on a 3-torus, or fully chaotic. Various bifurcations, including hard Hopf bifurcations and saddle-node bifurcations at strong resonances and period-doubling bifurcations of a mode-locked 3-torus, are revealed. In particular, the phenomenon of the period-doubling cascade of a resonant spiral tip trajectory is reported.
Hwang
Sm
National Creative Research Initiative Center for Neurodynamics and Department of Physics, Korea University, Seoul 136-701, Korea.
Gyu Choe W
Lee
KJ