Controlling turbulence in excitable media by applying boundary periodic pacing and gradient force

– Spiral wave and turbulence control in excitable media by applying periodic pacing on system’s boundary is investigated. It is found that spiral waves can be always successfully controlled by boundary periodic forcing with suitable forcing amplitude and frequency. Turbulence caused by spiral-wave breakup is uncontrollable by the boundary pacing, whatever the forcing amplitude and frequency, if the system parameters are in the backfiring (Phys. Rev. E, 48 (1993) R1635) region. We find further that gradient coupling can remarkably improve the control effect of the boundary pacing, by considerably enlarging the controllable parameter area. The problems of spiral waves and turbulence in excitable media have attracted great attention in nonlinear science and in diverse fields of natural science, in particular, chemical reactions and cardiac fibrillations. Spiral waves and turbulence are often harmful and it is an important task to seek some effective methods for spiral wave and turbulence control. In this regard, boundary periodic forcing is one of the most desirable methods [1–3]. On the one hand, boundary region control is very convenient, and on the other hand, simple periodic forcing does not require instant measurements and feedbacks of the system variables, and can be easily realized in practical situations. Nevertheless, this boundary pacing method is not always successful. For instance, some experiments explored the use of boundary periodic pacing for cardiac defibrillation [4–9]. They found that the pacing had only local effect, and (∗) E-mail: [email protected]