The Burgers-FKPP advection-reaction-diffusion equation with cut-off

We investigate the effect of a Heaviside cut-off on the front propagation dynamics of the so-called Burgers-Fisher-Kolmogoroff-Petrowskii-Piscounov (Burgers-FKPP) advection-reaction-diffusion equation. We prove the existence and uniqueness of a “critical” travelling front solution in the presence of a cut-off in the reaction kinetics and the advection term, and we derive the leading-order asymptotics for the speed of propagation of the front in dependence on the advection strength and the cut-off parameter. Our analysis relies on geometric techniques from dynamical systems theory and specifically, on geometric desingularisation, which is also known as “blow-up”.