Theory and simulation of higher-order cyclotron damping

The infinity of roots for real wavenumber k and complex frequency ω of the dispersion relation for transverse electromagnetic waves propagating in a thermal plasma parallel to an applied magnetic field B are studied theoretically and observed in numerical simulations. In addition to the usual weakly damped whistler and ion cyclotron roots, there are infinitely many more heavily damped electron (ion) roots characterized by real frequency near the gyrofrequency and damping rate proportional to the wavenumber. The electron modes have been observed in a thermal electromagnetic numerical simulation plasma and their dispersion agrees well with finite temperature linear theory. These modes may be observable experimentally.