Inner patterns and front propagation of dynamic random impurity model

We investigate a simple model, the so-called dynamic epidemic model, for the evolution of an advancing interface through a medium containing mobile impurities. A short range repulsion between the front and the impurities leads to an aggregation process along the front, and to the trapping of aggregates. The amplitude of this self-organization for collective impurity trapping is analyzed in two dimensions. A relationship exists between individual motion and the aggregation of particles. The results indicate that self-organizing features are different behind and on the front.