Figure 2

Maps of the growth rate \(\Gamma\) on the \(k_1 - k_2\) plane for \(\kappa =3\), \(\Psi _{1,0} =\Psi _{2,0} =0.1\), and perturbation wavenumber (a) \(K =0.1\); (b) \(K =0.4\); (c) \(K =1.9\); (d) \(K =3.4\). The values of K are chosen so that they illustrate the variability of the growth rate patterns in the best possible way.