Nonlinear self-distortion of electromagnetic waves in a magnetoplasma: Arbitrary direction of magnetic field

Using an elementary approach, the phenomenon of self-distortion of an amplitude modulated EM wave (extraordinary mode) in a magnetoplasma has been studied for the general case of group velocity not aligned with the phase velocity. The nonlinearity in the plasma arises because of modulation of the temperature-dependent collision frequency of electrons by the wave. In the case of whistlers, the fractional change in the index of modulation of the wave due to nonlinearity is shown to increase rapidly with increasing angle between the wave vector and the magnetic field. In the case of high frequency waves, the angular dependence of self-distortion is less pronounced.