On-off intermittency in a high-dimensional model of randomly driven parallel pumping

A model of parallel pumping with many interacting parametric spin-wave pairs is investigated numerically. Two ways of obtaining on-off intermittency in the time series of absorption are discussed: random or chaotic modulation of the rf field amplitude or of the dc field, slow in comparison with the rf field frequency. If the possibility of thermal excitation of spin waves is neglected, only one spin-wave pair is excited above the intermittency threshold and exhibits bursts. In the opposite case, a phenomenon of widening of the phase space in the presence of thermal noise is observed: a packet of parametric spin waves is excited with frequencies close to half the pumping frequency. This modifies quantitatively, but not qualitatively the characteristics of on-off intermittency in the presence of thermal noise.