Strange nonchaotic attractor of Hunt and Ott type in a system with ring geometry

The physical realizable system of ring structure, with a fixed irrational ratio of basic frequencies of external driving (the golden mean) manifests a strange nonchaotic attractor (SNA), similar to the attractor in the abstract map on a torus proposed and analyzed earlier by Hunt and Ott as an example of robust SNA. Simulation of the dynamics is provided basing on the numerical integration of the corresponding non-autonomous system of differential equations with quasi-periodic coefficients. It has been demonstrated that in terms of appropriately chosen phase variables the dynamics on the characteristic period is consistent with the topology of the mapping of Hunt and Ott. It has been shown that the birth of SNA corresponds to the criterion of Pikovsky and Feudel. Numerical calculations show that the Fourier spectra in sustained mode is of intermediate class between the continuous and discrete spectra (the singular continuous spectrum).