title: Statistical properties of directed avalanches.
abstract: A two-dimensional directed stochastic sandpile model is studied both numerically and analytically. One of the known analytical approaches is extended by considering general stochastic toppling rules. The probability density distribution for the first-passage time of stochastic process described by a nonlinear Langevin equation with power-law dependence of the diffusion coefficient is obtained. Large-scale Monte Carlo simulations are performed with the aim to analyze statistical properties of the avalanches, such as the asymmetry between the initial and final stages, scaling of voids and the width of the thickest branch. Comparison with random walks description is drawn and different plausible scenarios for the avalanche evolution and the scaling exponents are suggested.
authors.affiliation: Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna, Russia. nadezhda@imbm.bas.bg
authors.forename: N Zh
authors.initials: NZh
authors.lastname: Bunzarova