Torus-doubling process via strange nonchaotic attractors

Torus-doubling bifurcations typically occur only a finite number of times. It has been assumed that torus-doubling bifurcations in quasiperiodically forced systems are interrupted by the appearance of strange nonchaotic attractors (SNAs). In the present Letter, we study a quasiperiodically forced noninvertible map and report the occurrence of a torus-doubling process via SNAs. The mechanism of this process is numerically clarified. Furthermore, this process is experimentally demonstrated in a switched-capacitor integrated circuit.

► We report the occurrence of a torus-doubling process via strange nonchaotic attractors (SNAs).
► The process consists of the gradual fractalization of a torus and the Heagy–Hammel transition.
► The torus-doubling process via SNAs is also experimentally demonstrated in an electronic circuit.