ON THE ORIGIN OF TRAVELING PULSES IN BISTABLE SYSTEMS

The interaction between a pair of Bloch fronts forming a traveling dom ain in a bistable medium is studied. A parameter range beyond the none quilibrium Ising-Bloch bifurcation is found where traveling domains co llapse. Only beyond a second threshold the repulsive front interaction s become strong enough to balance attractive interactions and asymmetr ies in front speeds, and form stable traveling pulses, The analysis is carried out for the forced complex Ginzburg-Landau equation. Similar qualitative behavior is found in the bistable FitzHugh-Nagumo model. ( C) 1997 Published by Elsevier Science B.V.