Resonant sheath heating in weakly magnetized capacitively coupled plasmas due to electron-cyclotron motion.

Abstract

An electron heating mechanism based on a resonance between the cyclotron motion of electrons and the radio frequency sheath oscillations is reported in weakly magnetized capacitively coupled plasmas at low pressure. If half of the electron cyclotron period coincides with the radio frequency period, then electrons will coherently collide with the expanding sheath and gain substantial energy, which enhances the plasma density. A relation between the magnetic field and the driving frequency is found to characterize this resonance effect and the kinetics of electrons are revealed at resonance conditions for various driving frequencies.