Dynamic regimes occurring for normalized stimulus amplitude ζ = 3.6301.

A limit cycle appearing as periodic oscillations is a closed orbit in state space. An invariant torus indicates quasi-periodic oscillations that manifest themselves in the power spectra with peaks at incommensurate frequencies. A strange attractor is a bounded attracting set in which all trajectories are unstable and nearby trajectories locally diverge from each other exponentially, as evidenced by a positive Lyapunov exponent, as well as a broadband power spectrum.