Pulses in a Gierer-Meinhardt equation with a slow nonlinearity. (English) Zbl 1282.35049
Summary: We study in detail the existence and stability of localized pulses in a Gierer-Meinhardt equation with an additional “low” nonlinearity. This system is an explicit example of a general class of singularly perturbed, two component reaction-diffusion equations that goes significantly beyond well-studied model systems such as Gray-Scott and Gierer-Meinhardt. We investigate the existence of these pulses using the methods of geometric singular perturbation theory. The additional nonlinearity has a profound impact on both the stability analysis of the pulse – compared to Gray-Scott/Gierer-Meinhardt-type models a distinct extension of the Evans function approach has to be developed – and the stability properties of the pulse: several (de)stabilization mechanisms turn out to be possible. Moreover, it is shown by numerical simulations that, unlike the Gray-Scott/Gierer-Meinhardt-type models, the pulse solutions of the model exhibit a rich and complex behavior near the Hopf bifurcations.
MSC:
35B36 | Pattern formations in context of PDEs |
35K57 | Reaction-diffusion equations |
35B25 | Singular perturbations in context of PDEs |
35B35 | Stability in context of PDEs |
35K45 | Initial value problems for second-order parabolic systems |