Spatio-temporal irregularity in an excitable medium with shear flow

V. N. Biktashev, I. V. Biktasheva, A. V. Holden, M. A. Tsyganov, J. Brindley, N. A. Hill

Submitted to PRL 1998/11/16. Accepted to PRE 1999/04/02

We consider an excitable medium moving with relative shear, subjected  to a localised disturbance which, in a stationary medium, would produce a pair of spiral waves. The spiral waves so created are distorted and then broken by the motion of the medium.  Such breaks generate new spiral waves, and so a ``chain reaction'' of spiral wave births and deaths is observed. This leads to a complicated spatio-temporal pattern, the ``frazzle gas'' (term suggested in [M. Markus et al., Nature 371:402-404, 1994], which eventually fills the whole medium.  In this paper, we display and interpret the main features of the pattern.