ROTATED SANDPILES - THE ROLE OF GRAIN REORGANIZATION AND INERTIA

We present a coupled-map lattice model of a sandpile which relaxes via the dual mechanisms of surface how and bulk reorganization. We focus on the situation where reorganization dominates flow and examine the r esponse of our model to rotation; the event size distribution is analy zed as a function of the model parameters. In regions of phase space w here the effects of excess volume and grain inertia are both large, we see a characteristic double peak in the size distribution, indicating a preferred scale for large avalanches. We explain this, and the asso ciated configurational memory, using a simple picture of grain-cluster coupling. We next compare the distribution functions with those produ ced by random deposition and, in the latter case, present results for the event size distribution function in terms of the size of the depos ited grains. Finally, we show the connection of our model to earlier s cale-invariant models, and discuss our results.