两层耦合可激发介质中螺旋波转变为平面波

Transformation of spiral wave to plan wave in the two layers of coupled excitable media

采用Br-Eiswirth模型研究了两层耦合可激发介质中螺旋波的动力学,两层介质通过网络连接,即在每一层介质上,每一列选一个可激发单元作为中心点,在一层介质上同一列的可激发单元只与另一层介质上对应的中心点及其8个邻居有耦合.数值模拟结果表明:通过这种局部耦合,在适当小的耦合强度下两耦合螺旋波可实现同步,增大耦合强度会导致螺旋波漫游和漂移,造成螺旋波不同步,观察到螺旋波与静息态、低频平面波和不规则斑图共存现象.在适当强的耦合强度下,还观察到两螺旋波转变成同步的平面波消失现象.对产生这些现象的物理机理做了讨论.

The dynamics of spiral waves in a two-layer coupled excitable medium is studied by using the B^r-Eiswirth model. The two layers of medium are connected via network, i.e., a excitable unit is selected in each column of an excitable medium as a central point, and all excitable units in the same column of a layer medium are connected only with the corresponding central point and its eight neighbors in the opposite medium. The numerical results show that when the coupling strength is appropriately small, the two coupled spiral waves via local coupling can achieve their synchronization. Increasing coupling strength will induce meandering and drifting of spiral waves, leading to a desynchrony between the coupled spiral waves. The spiral wave with the resting state, low frequency plan wave and irregular pattern are observed to coexist. The coupled spiral waves via the transformation of spiral wave to synchronous plane wave disappear if the coupling strength is appropriately chosen. The physical mechanisms behind these phenomena are discussed.