SCALING OF REACTION FRONTS UNDER QUENCHED DISORDER

The dynamics of fronts in diffusion-limited reactions A + B --> C with initially segregated reactants in strongly disordered media is studied. The scaling of the front width, w, in the asymptotic limit w similar to t(alpha), is analyzed as a function of the ''disorder strength'' and spatial dimensionality, d. We show that exponent alpha in d dimensions is a monotonic decreasing function of disorder strength, as measured from diffusive properties of reactants, We also find that alpha has a mean field behavior for d greater than or equal to 2. Scaling anomalies are observed in related quantities such as nearest neighbor distance, midpoint fluctuations and concentration profiles of reactants near the center of the front.