The modulation instability of whistlers

An analysis is presented of the striction-type parametric instability of a whistler in a collisional plasma. Attention is given to the propagation of the low-frequency density perturbation along the external magnetic field as well as at an angle to the field in the case of magnetoacoustic wave propagation. Wavenumber ranges are determined in which modulation instability of the whistler can exist, and threshold values of collision frequencies are found above which the instability cannot exist. It is shown that the instability develops with particular rapidity in the case of the propagation of the low-frequency perturbation along the external magnetic field. A numerical solution is obtained for the nonlinear decay of the pumping whistler into two satellites and a low-frequency perturbation.