Scattering of ion-cyclotron alfvén waves by drift waves in a collisional plasma

The temporal modulation of ion-cyclotron Alfvén waves by extremely low-frequency resistive drift waves is considered. It is argued that in a collisional plasma the contribution of the Joule heating nonlinearity would far exceed that of the usual ponderomotive force. An expression for the growth rate of the thermal modulational instability is presented. The relevance of our study to the lower part of the ionosphere is pointed out.