Figure 3: The panels show the features of threshold amplitudes Acr and Bcr in the coupled mode when helicity is included. In panel (a) we have plotted the amplitudes for ε = π/2 and the panel (b) has been plotted for ε = 3π/10. Values of parameters are S = 0.3 eV, D = 1.2 × 10-1 eV, I = 1.8158 × 103 Å2 amu, λ = 4 × 10-3 eV, and h = 5. Arrows point further regions of stability.