Electromagnetic ion cyclotron (EMIC) waves are excited near the magnetic equator by anisotropic ring current ions with energies near a few tens of keV. We investigate the instability and the path-integrated gain of EMIC waves during wave propagation. Calculations are performed by a global core density model, a field-aligned density model and particularly the hot ring current ions modeled by a kappa distribution. Simulating results show that the instability of EMIC waves is influenced primarily by the parameters of hot ring current ions, the wave normal angle and the composition of background p...
