Anisotropic interface depinning: Numerical results

We study numerically a stochastic differential equation describing an interface driven along the hard direction of an anisotropic random medium. The interface is subject to a homogeneous driving force, random pinning forces, and surface tension. In addition, a nonlinear term due to the anisotropy of the medium is included. The critical exponents characterizing the depinning transition are determined numerically for a one-dimensional interface. The results are the same, within errors, as those of the ``directed percolation depinning'' (DPD) model. We therefore expect that the critical exponents of the stochastic differential equation are exactly given by the exponents obtained by a mapping of the DPD model to directed percolation. We find that a moving interface near the depinning transition is not self-affine and shows a behavior similar to the DPD model. {} 1996 The American Physical Society.