Propagation of spiral waves in anisotropic media: from waves to stripes

The effects of anisotropic diffusion on the propagation of spiral waves in excitable media are studied numerically by means of time-linearized methods in very refined meshes and with very small time steps. It is shown that th e anisotropy of the inhibitor's diffusivity tensor does not play as importa nt role on wave propagation as that of the activator. It is also shown that the off-diagonal components of the activator's diffusivity tensor cause st retching of the activator's concentration along the principal directions of this tensor, and that a large difference between the diffusion coefficient s in the x- and y-directions may result in the spiral wave annihilation and stripe formation. (C) 2001 Elsevier Science Ltd. All rights reserved.