Kogan Oleg, O'Keeffe Kevin, Myers Christopher R
Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.
Center for Applied Mathematics, Cornell University, Ithaca, New York 14853, USA.
Phys Rev E. 2017 Aug;96(2-1):022220. doi: 10.1103/PhysRevE.96.022220. Epub 2017 Aug 29.
We study the coupling of a Fisher-Kolmogorov-Petrovsky-Piskunov (FKPP) equation to a separate, advection-only transport process. We find that an infinitesimal coupling can cause a finite change in the speed and shape of the reaction front, indicating the fragility of the FKPP model with respect to such a perturbation. The front dynamics can be mapped to an effective FKPP equation only at sufficiently fast diffusion or large coupling strength. We also discover conditions when the front width diverges and when its speed is insensitive to the coupling. At zero diffusion in our mean-field description, the downwind front speed goes to a finite value as the coupling goes to zero.
