An investigation is made on the instabilities of electrostatic oxygen ion (O+
) cyclotron and ion acoustic waves in a model plasma consisting of background hot electrons, background cold protons (H+
), and strongly anisotropic oxygen ion beams. It is shown that the lower frequency and electrostatic O+
ion cyclotron and ion acoustic waves may be excited by upgoing O+
ion beams on auroral field lines. Upgoing O+
ion beams may be an important source of free energy for the lower frequency and electrostatic instabilities on auroral field lines.