European Journal of Applied Mathematics

Research Article

Diffusivity determination in nonlinear diffusion

Carmen Cortázara1, Manuel Elguetaa1 and Juan Luis Vázqueza2

a1 Departamento de Matemática, Pontificia Universidad Católica, Casilla 6177, Santiago de Chile, Chile

a2 Departamento de Matemáticas, Universidad Autónoma de Madrid, 28049, Madrid, Spain

Abstract

We are concerned with the problem of determining the diffusivity D of a diffusion process governed by the equation ut = (Dux)x', under the assumption that D depends on u. The main point consists in the observation that there exist solutions of travelling-wave type and that the dependence D = D(u) can be explicitly found in terms of the profile of such solutions. The property of finite propagation speed is required for this method to work. We propose two concrete implementations of the inverse problem, and give a rigorous mathematical proof of our statements. We also describe the application of the travelling-wave method to another interesting class of nonlinear parabolic equations.

(Received November 05 1900)