Langevin and Fokker-Planck equations for kinetic growth and aggregation processes

A theoretic approach to account for the intrinsic fluctuations of kinetic growth and aggregation processes in their equations of motion is presented. Langevin equations with multiplicative noise terms, are derived for continuous variants of the Eden models and for the transparent diffusion-limited aggregation. The related Fokker-Planck equations are derived as well. Fluctuations are irrelevant for the Eden models but are probably relevant for the diffusion-limited aggregation. The possible use of the stochastic equations to regularise their effects in this latter case is briefly discussed.