EXPERIMENTAL CONFIRMATION OF THE THEORY FOR CRITICAL EXPONENTS OF CRISES

We investigate the scaling of the average time tau between intermittent bursts for a chaotic system that undergoes a homoclinic tangency crisis, which causes a sudden expansion in the attractor. The system studied is a periodically driven (frequency f), nonlinear, magnetoelastic ribbon. The observed behavior of tau is well fit by a power-law scaling tau approximately \f-f(c)\-gamma, where f = f(c) at the crisis. We identify the unstable periodic orbit mediating the crisis, and determine its linearized eigenvalues from experimental data. The critical exponent gamma found from the scaling of tau is shown to agree with that theoretically predicted for a two-dimensional map on the basis of the eigenvalues of the mediating periodic orbit.