非均匀可激发介质中的稀密螺旋波

Sparse and dense spiral waves in heterogeneous excitable media

在非均匀可激发介质中,采用Barkley模型数值模拟了稀螺旋波和密螺旋波,并对二者的动力学行为随参数的变化进行了研究.结果发现:稀螺旋波的旋转频率随参数b的增加迅速减小,之后趋于饱和,显示出不同于密螺旋波的行为;两种螺旋波的周期和波长随参数ε和非均匀区域尺寸R的增加而增加,相对稀螺旋波而言,密螺旋波的性质对R的依赖更为敏感;稀螺旋波端点的波速随R的增加而减小,与密螺旋波波速变化趋势相反.另外,由于非均匀区域的影响,当ε或b超过某一临界值时,螺旋波臂上出现缺陷点.

Dynamic behaviors of sparse and dense spirals are investigated numerically based on a Barkley model in heterogeneous excitable media. It is found that the rotating frequency of sparse spiral wave decreases rapidly with b increasing and then tends to saturation, which is different from that of dense spiral wave. The period and wavelength of dense spiral wave increase with the increase of parameter e or the size/~ of localized inhomogeneity, which depends more sensitively on the size R than those of sparse sprial wave. The change of the speed of dense spiral wave tip with R is opposite to that of the sparse spiral wave tip. In addition, inhomogeneous effect gives rise to a defect point in arm of each of the two spiral waves when e or b increases above a critical value.