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Research Papers
The leading edge of a free boundary interacting with a line of fast diffusion
L. A. Caffarellia, J.-M. Roquejoffreb a The University of Texas at Austin, Mathematics Department RLM 8.100, 2515 Speedway Stop C1200, Austin, Texas 78712-1202, U.S.A.
b Institut de Mathématiques de Toulouse (UMR CNRS 5219), Université Toulouse III, 118 route de Narbonne, 31062 Toulouse cedex, France
Abstract:
The goal of this work is to explain an unexpected feature of the expanding level sets of the solutions of a system where a half-plane in which reaction-diffusion phenomena take place exchanges mass with a line having a large diffusion of its own. The system was proposed by H. Berestycki, L. Rossi and the second author as a model of enhancement of biological invasions by a line of fast diffusion. It was observed numerically by A.-C. Coulon that the leading edge of the front, rather than being located on the line, was in the lower half-plane.
We explain this behavior for a closely related free boundary problem. We construct travelling waves for this problem, and the analysis of their free boundary near the line confirms the predictions of the numerical simulations.
Keywords:
expanding level sets, reaction-diffusion phenomena, line of fast diffusion.
Received: 29.07.2019
Citation:
L. A. Caffarelli, J.-M. Roquejoffre, “The leading edge of a free boundary interacting with a line of fast diffusion”, Algebra i Analiz, 32:3 (2020), 149–179; St. Petersburg Math. J., 32:3 (2021), 499–522
Linking options:
https://www.mathnet.ru/eng/aa1703 https://www.mathnet.ru/eng/aa/v32/i3/p149
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