Ion cyclotron instability of drifting plasma clouds

Ion cyclotron instability has been investigated in a dipole geomagnetic field where the particles are allowed to drift. After injecting the particles in an extended region around local midnight we have computed the ion cyclotron instability growth rates at various local times using the drift-convoluted distribution function. The computations indicate that the frequency dispersive effects can be produced by either the drift effects or changing the cold plasma density.