Mode conversion of waves in the ion-cyclotron frequency range in magnetospheric plasmas.

Waves in the ion-cyclotron range of frequencies with linear polarization detected by satellites can be useful for estimating the heavy ion concentrations in planetary magnetospheres. These waves are considered to be driven by mode conversion (MC) of the fast magnetosonic waves at the ion-ion hybrid resonances. In this Letter, we derive analytical expressions for the MC efficiency and tunneling of waves through the MC layer. We evaluate the particular parallel wave numbers for which MC is efficient for arbitrary heavy ion/proton ratios and discuss the interpretation of the experimental observations.