Features of generation of broadband waves of the ion-cyclotron and the ion-acoustic type in the auroral ionosphere

To study instabilities caused by inhomogeneities of the electric field and plasma density in the auroral zone, numerical algorithms are developed and computational modeling are performed for different conditions in the background plasma. It is shown that the dispersion relation has unstable solutions in a wide range of frequencies and wavenumbers. These solutions manifest themselves in satellite observations as a broadband spectrum of electrostatic perturbations. In addition to inhomogeneous energy-density-driven waves of ion-cyclotron type, ionospheric structures are capable of destabilizing oblique ion acoustic waves modified by a shear in the parallel drift of ions.