HOW DOES THE GEOMETRY AFFECT THE CRITICALITY IN 2-COMPONENT SPREADINGPHENOMENA

We study numerically the two-component spreading model (SMK) for conca ve and convex radial growth two-dimensional geometries. The seed is ch osen to be an occupied circle line, and the growth spreads inside the circle (concave geometry) or outside the circle (convex geometry). On the basis of a generalized diffusion-annihilation equation for domain evolution, we derive mean-field relations that describe quite well the results of numerical investigations. We conclude that the intrinsic u niversality of the SMK does not depend on the geometry, and that the d ependence of criticality on curvature observed in numerical experiment s is only an apparent effect. We discuss the dependence of the apparen t critical exponent chi(a) upon the growth geometry and initial condit ions.