Critical behavior of sandpile vortices under variable charge

In the following, we consider a sandpile cellular automaton model (height version), which also takes account of lattice cyclicity for variable charge of grains projected upon the board. The size of the charge or additional grains of sand used to upset the equilibrium and to induce an avalanche is found to affect the distributional forms and in particular the convergence of the estimate for the dynamic exponent. Exponent estimates show slow variation with lattice dimensionL and some evidence of evolution with charge. The scaling region is limited in all cases with noisy decay at all levels of charge. Results presented extend the work of Duarte and Goncalves (1990) on the triangular lattice.