Tunable pinning of burst waves in extended systems with discrete sources

We study the dynamics of waves in a system of diffusively coupled discrete nonlinear sources. We show that the system exhibits burst waves which are p eriodic in a traveling-wave reference frame. We demonstrate that the burst waves are pinned if the diffusive coupling is below a critical value. When the coupling crosses the critical value the system undergoes a depinning in stability via a saddle-node bifur cation, and the wave begins to move. We o btain the universal scaling for the mean wave velocity just above threshold . [S0031-9007(98)07893-4].