Zero-dimensional toy model illustrating the effect of the delay. In each panel the green curve represents the evolution of the delay with time for a given B_ϕ, indicated in the lower panels as the blue curve. The dashed line represents time. The histogram on the right-hand side represents the resulting source term S normalized in arbitrary units. Panels a and b illustrate the case of a weakly nonlinear delay (α = −1), and panels c and d show a nonlinear delay (α = −2). Panels a and c show a short effective delay (e.g., and τ₀ = 3 · 10⁻⁵ P_cyc) and panels b and d show a long effective delay (e.g., and τ₀ = 10⁻³ P_cyc).