Inwards propagating waves in heterogeneous limit cycle media

We investigate the dynamics of an oscillatory reaction–diffusion medium composed of two adjacent uniform regions where inwards propagating (IP) waves are generated in at least one of them. As was shown, IP waves display unusual “backward” motion directed towards their origin. Here pseudo-reflection of the IP waves at the interface between regions is discussed. Such an interface can drive pseudo-reflected IP waves at a frequency which, surprisingly, exceeds the natural frequencies of both regions. Simple models of two unidirectionally coupled oscillators, and a single oscillator with a stepwise constant bias, are analyzed to help understand the functioning of the interface.