Effect of Collisions on Ion Cyclotron Waves

The behavior of a transverse electromagnetic wave propagating in the direction of a uniform magnetic field in an unbounded fully ionized plasma is examined. Linearized kinetic equations with collision terms of the Krook-Bhatnager-Gross type extended by Liboff to include interspecies collisional effects are used in the solution of an inhomogeneous wave equation. The region of ion cyclotron resonance is closely investigated, and the transition of the dispersion relation from the low-temperature collision-dominated regime to the high-temperature regime is observed. It is found that moments of the kinetic equations are adequate in the collision-dominated regime, but the kinetic equation for the ions must be used at higher temperatures. At these higher temperatures a complete solution of the problem requires numerical work near the source plane. Far from the source, explicit solutions for the fields can be written.