in the upper panels of this group, most of the kinetic energy of the modes is confined in the central region. The most notable difference between the presented modes is that the unstable one has some energy deposited also in the radiative envelope, whereas the stable one has almost no energy in this region. This is due to the fact that the unstable mode has been partially reflected at the ICZ and is trapped in two cavities: the core and the outer layers. That energy, although its amount is small when compared to the amount trapped in the core, is sufficient for the $\kappa$ mechanism, operating in the $Z-$bump, to efficiently drive the pulsations. This is visible in the behaviour of differential work integral - there is a maximum around $\log T=5.2$ and it dominates over the damping in the core. On the contrary, the stable mode has not been reflected at ICZ because it does not have a node of eigenfunction there. That means that it penetrates the core with high amplitude and is effectively damped there. The above behaviour of $E_k$ explains the pattern of local maxima and minima of $\eta$ described earlier on.

For Model2 we also 