The Dynamics of Curved Fronts: Beyond Geometry
  We derive a new set of kinematic equations for front motion in two-dimensional bistable media. The equations generalize the geometric approach by complementing the equation for the front curvature with an order parameter equation associated with a nonequilibrium Ising-Bloch bifurcation. The resulting equations capture the core structure of spiral waves and spontaneous spiral-wave nucleation. 
Aric Hagberg (http://t7.lanl.gov/People/Aric) and Ehud Meron   (http://www.bgu.ac.il/BIDR/research/staff/meron.html)