LOCAL ISOTROPY AND GEOMETRY OF PARTICLE-FLUX LINES IN DIFFUSION-LIMITED AGGREGATION

We present a theoretical description of the branch orientation and the geometry of walker flux lines in diffusion limited aggregation (DLA). It is based on the self-similarity and non-directedness of the branch structure and explains recent numerical results on the probability di stribution of the branch orientation and the angle of particle attachm ent. Our results support the idea that asymptotically large off-lattic e DLA clusters are locally isotropic and every individual walker flux line exhibits a certain type of self-similarity.