Dynamic characteristics of a subcritical bifurcation with inversion symmetry

Phase and amplitude dynamics of a subcritical period-doubling bifurcation are experimentally characterized in the nonlinear strain response (at f≊10 kHz) of a magnetostrictive oscillator. Low frequency (f_mod≤0.1 Hz) modulation of the observed subcritical bifurcation provides a phase-reversing time series whose power spectrum tends to conceal frequency components. An event counting technique developed for characterizing the phase-slip dynamics of the time series reveals a substantial component at half the modulation frequency (f/2) as well as at f. The event counting technique is applied to observe stochastic resonance for the first time in a tristable system.