Robust entrainment phenomena of oscillations by delay time in the photosensitive Oregonator model

The influences of delayed feedback on the oscillating behaviors are numerically investigated by using the photosensitive Oregonator model with a Hopf point. We find that the time delay in the robust entrainment phenomena determines the time scale of the system, that is, T-m=(tau+delta)/N (N=1,2,center dot), where T-m is the mean period of the oscillation and delta is a small constant compared with the delay time tau. Further, our numerical simulation shows that, when the system has a characteristic period T-0 under the feedback with time delay, there exists an asymptotical line delta=delta T-0(0) (delta(0) independent of any parameters) in the entrainment region with increasing strength of the feedback control c; when the system has no characteristic period, the above linear relation is also kept, and delta decreases with increasing c.