We experimentally characterize the whole shape of growth cells in directional solidification, from their tip to their grooves, and in a large domain of control parameter. For this a library of cell shapes is determined and fitted to a class of definite shape functions. This first global characterization of cell geometry in both the real space and the control parameter space provides a firm grou...

We use a computationally efficient phase-field formulation [B. Echebarria, Phys. Rev. E 70, 061604 (2004)] to investigate the origin and dynamics of sidebranching in directional solidification for realistic parameters of a dilute alloy previously studied experimentally [M. Gorgelin and A. Pocheau, Phys. Rev. E 57, 3189 (1998)]. Sidebranching is found to result either from noise amplification or...

We study initial transient stages in directional solidification by means of a non-variational phase field model with fluctuations. This model applies for the symmetric solidification of dilute binary solutions and does not invoke fluctuation-dissipation theorem to account for the fluctuation statistics. We devote our attention to the transient regime during which concentration gradients are bui...