Figure 3. AAD control by continuous illumination of circular light spots of different sizes and durations.

Panel A shows representative dragging events as a spiral wave core is relocated from the center of the simulation domain to the periphery, with light spots of diameter $d$=$0.175$, $0.275$ and $0.4$ cm, respectively. In each case, the real trajectories of the spiral tip is marked with solid red lines on top of the voltage map. When $d$ is large, the spiral tip exhibits a tendency to move along a linear path, as opposed to the cycloidal trajectory at small $d$. With $d=0.275\text{cm}$, (B) probability of successful dragging ($P_{drag}$) increases, and (C) spiral core relocation time (${\tau }_{min}$) decreases, with increasing $d$. In each of the afore-mentioned cases, the dragging process is illustrated with zero dark interval (${\tau }_{dark}$) and minimal light interval (${\tau }_{light}$). (D) With finite non-zero ${\tau }_{dark}$, $P_{drag}$ increases with shortening of ${\tau }_{dark}$, for light stimulation of afixed cycle length ($200$ ms). (E) Dependence of $P_{drag}$ on ${\tau }_{dark}$, for three different light intervals (${\tau }_{light}$). (F) Schematic representation of the drag angle $\theta$ and the distance ($r$) between the starting location of the spiral tip and the location of the applied light spot. (G) Distribution of $P_{drag}$ at different $\theta$ and $r$, thresholded at 50%. (H) AAD control is effectuated by alternate transitions between functional (free wave) and anatomical (anchored wave) reentry. The phase singularity of the free spiral is marked with a black asterisk, whereas, the point of attachment of the anchored wave to the heterogeneity is marked with a black dot.