STRANGE NONCHAOTIC ATTRACTOR IN A QUASI-PERIODICALLY FORCED CIRCLE MAP

We show that in the quasiperiodically forced circle map strange non-ch aotic attractors can appear for non-linearities far from the border of chaos. The destruction of a two-frequency quasiperiodic torus connect ed with the appearance of a strange non-chaotic attractor is described in detail. This strange non-chaotic attractor is characterized by log arithmically slow diffusion of the phase. It is shown that in this reg ime the high-order phase-locking states disappear and the rotation num ber varies rather smoothly with the parameters.