Electric-field-sustained spiral waves in subexcitable media.

We present numerical evidence that, in the presence of a suitable electric field, an isolated broken plane wave retracting originally in subexcitable media can propagate continuously and eventually evolve into a rotating spiral. Simulations for the FitzHugh-Nagumo, the Barkley, and the Oregonator models are carried out and the same electric-field-sustained spiral phenomena are observed. Semianalytical results in the framework of a kinematic theory are quantitatively consistent with the numerical results.