Plasma heating from upper-hybrid mode conversion in an inhomogeneous magnetic field

Abstract

Large-amplitude short-wavelength electrostatic fields can be generated at the upper-hybrid resonance layer due to the mode conversion process when an incident wave of appropriate frequency falls on a plasma. As a consequence, a host of nonlinear and kinetic phenomena can take place. Among them, the generation of energetic electrons due to the breaking of adiabatic electron motion in the wave field, the enhancement of electron second harmonic cyclotron heating at the double resonance (ωuh = 2ωce), and parametric instabilities in which the upper-hybrid mode decays into another upper-hybrid mode and a low-frequency mode. Investigations of these phenomena through the use of computer simulations are presented. The parametric process is observed to produce a substantial number of energetic ions localized at the resonance layer.