THE EVOLUTION OF TRAVELING WAVES IN REACTION-DIFFUSION EQUATIONS WITHMONOTONE DECREASING DIFFUSIVITY .2. ABRUPTLY VANISHING DIFFUSIVITY

In this paper we continue our study of some of the qualitative feature s of chemical polymerization processes by considering a reaction-diffu sion equation for the chemical concentration in which the diffusivity vanishes abruptly at a finite concentration. The effect of this diffus ivity cut-off is to create two distinct process zones; in one there is both reaction and diffusion and in the other there is only reaction. These zones are separated by an interface across which there is a jump in concentration gradient. Our analysis is focused on both the initia l development of this interface and the large time evolution of the sy stem into a travelling wave form. Some distinct differences from our p revious analysis of smoothly vanishing diffusivity are found.