ON-OFF INTERMITTENCY IN RANDOMLY DRIVEN PARALLEL PUMPING

A model of parallel pumping with many interacting parametric spin-wave pairs is investigated numerically. On-off intermittency is obtained i n the time series of absorption when the rf field amplitude is varied randomly in time, slowly in comparison with the rf field frequency, an d when its mean value exceeds slightly the parallel pumping instabilit y threshold. If the interactions between parametrically and thermally excited spin waves are neglected, only one parametric spin-wave pair i s strongly excited and exhibits intermittent behaviour. In the opposit e case a packet of parametric spin waves with frequencies close to hal f the pumping frequency may be excited. This modifies quantitatively, but not qualitatively th intermittency characteristics in the presence of thermal noise.