Spiral wave break-up and planar front formation in two-dimensional reactive-diffusive media with straining

The propagation of spiral waves in two-dimensional reactive–diffusive media subject to a velocity field with straining is studied numerically. It is shown that, depending on the magnitude of the strain rate, the effects of straining on wave propagation can be classified in three regimes: the no break-up, the transitional and the break-up regimes. In the no break-up regime, the spiral wave preserves its integrity, whereas, in the transitional one, the spiral wave is deformed and transformed into a curved front which propagates almost along one of the principal directions of the strain rate tensor. In the break-up regime, spiral waves are broken up into many spiral waves, and planar fronts aligned with the principal direction of the strain rate tensor corresponding to elongation/stretching are formed. These fronts may be split into two new ones or are bands, the thickness of which decreases as the strain rate is increased. 2003 Elsevier Inc. All rights reserved.