NONLINEAR COUPLING OF LOWER-HYBRID WAVES TO THE KINETIC LOW-FREQUENCYPLASMA RESPONSE IN THE AURORAL IONOSPHERE

A hybrid kinetic-fluid model is developed which is relevant to lower h ybrid spikelets observed in the topside auroral ionosphere [Vago et al ., 1992; Eriksson et al., 1994]. In contrast to previous fluid models [shapiro et al., 1995; Tam and Chang, 1995; Seyler, 1994; Shapiro et a l., 1993] our linear low frequency plasma response is magnetized and k inetic. Fluid theory is used to incorporate the nonlinear wave couplin g. Performing a linear stability analysis, we calculate the growth rat e for the modulational instability, driven by a lower hybrid wave pump . We find that both the magnetic and kinetic effects inhibit the modul ational instability.