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Synchronization of a spiral by a circularly polarized electric field (CPEF) in reaction-diffusion systems is investigated since they both possess rotation symmetry. It is found that spirals in different regimes (including rigidly rotating, meandering, and drifting spirals) can be forced to be rigidly rotating ones by CPEFs. Moreover, the rotational frequency of the entrained spiral is found to be synchronized with the frequency of the electric field in a ratio of 1:1. [ABSTRACT FROM AUTHOR]

The effect of a circularly polarized electric field on the Turing stripe patterns is studied. The numerical results show that stripe patterns may change to hexagonal wave patterns by choosing the intensity and the frequency of the circularly polarized electric field suitably. Our findings indicate that a pattern tends to organize itself to the pattern with the same symmetry of the applied field with the fact that compared to the stripe patterns, hexagonal wave patterns possess hexagonal symmetry which is closer to the rotation symmetry of the circularly polarized electric field. [ABSTRACT FROM AUTHOR]

The drift behavior of spiral waves under the influence of a polarized electric field is investigated in the light that both the polarized electric field and the spiral waves possess rotation symmetry. Numerical simulations of a reaction-diffusion model show that the drift velocity of the spiral tip can be controlled by changing the polarization mode of the polarized electric field and some interesting drift phenomena are observed. When the electric field is circularly polarized and its rotation follows that of the spiral, the drift speed of the spiral tip reaches its maximal value. On the contrary, opposite rotation between the spiral and electric field locks the drift of the spiral tip. Analytical results based on the weak deformation approximation are consistent with the numerical results. We hope that our theoretical results will be observed in experiments, such as the Belousov-Zhabotinsky reaction. [ABSTRACT FROM AUTHOR]

In a generic model of excitable media, we study the behavior of spiral waves interacting with obstacles and their dynamics under the influences of simple periodic mechanical deformation (PMD). Depending on the characteristics of the obstacles, i.e., size and excitability, the rotation of a pinned spiral wave shows different scenarios, e.g., embedding into or anchoring on an obstacle. Three different drift phenomena induced by PMD are observed: scattering on small partial-excitable obstacles, meander-induced unpinning on big partial-excitable obstacles, and drifting around small unexcitable obstacles. Their underlying mechanisms are discussed. The dependence of the threshold amplitude of PMD on the characteristics of the obstacles to successfully remove pinned spiral waves on big partial-excitable obstacles is studied. [ABSTRACT FROM AUTHOR]

A correction to the article "Drift of Spiral Waves Controlled by a Polarized Electric Field," published on January 6, 2006 is presented.

The termination of pinned spirals on a defect by means of local stimuli is studied. On a completely unexcitable defect, the elimination process is discussed and its corresponding mechanism is presented. Especially, the mechanism of unpinning spirals on a partially unexcitable defect, which has not been investigated so far, is explored. With fixed pacing frequency ωL, there exists a maximal radius Rmax above which the pinned spiral cannot be removed. It is found that the value of Rmax does not increase as ωL in a dynamical regime, forming a platform in the curves. Based on analyzing the dispersion relation on the spiral tip around the obstacle, the underlying mechanism is clarified. Also, it is found that when multiple spirals are pinned, the value of Rmax decreases on a partially unexcitable defect while the change is very slight on a completely unexcitable one. [ABSTRACT FROM AUTHOR]