Fig. 5

Existence and stability of ring solutions with inner radius $R_1$, with the indicated γ and $\beta =0.5$ in (20). The lower branch is always unstable (dotted lines). On the upper branch the stable ring (solid lines) can lose stability with dominant $\mathrm{mode}=2$ (solid circles), 3 (triangles), 4 (squares), etc. for decreasing h.