BRANCH-HEIGHT DISTRIBUTION IN DIFFUSION-LIMITED DEPOSITION

We analyze diffusion-limited aggregation (DLA) with a branchless needl e model. We modify the growth rules of our needles by assigning them a fractal dimension of D(b) almost-equal-to 1.7, the fractal dimension of DLA. We then construct a mean-field theory of the evolution of the number of needles having particular heights. Our model accounts for th e correlations within a needle. We argue that DLA is an isotropic frac tal with a scaling density profile and that the fractal dimension of t he individual branches should be the same as the dynamical dimension o f the aggregate.