Resonant-separatrix webs in stochastic layers of the twin-well Duffing oscillator

The excitation strength for the onset of a new resonant-separatrix in the stochastic layer of the Duffing oscillator is predicted through the energy change in minimum and maximum energy spectra. The widths of stochastic layers are estimated through the use of the maximum and minimum energy which can be measured experimentally. The energy spectrum approach, rather than the Poincare mapping section method, is applied to detect the resonant-separatrix web in the stochastic layer, and it is applicable for the onset of resonant layers in nonlinear dynamic systems. The analytical condition for the onset of a new resonant-separatrix in the stochastic layer is also presented. The analytical and numerical predictions are in good agreement.