Detection of localized hot electrons in low-pressure large-area microwave discharges

Abstract

A localized hot-electron region was observed in low-pressure (<3 mTorr) large-area microwave discharges. The region appears in the vicinity of the waveguiding plasma–dielectric interface in the place of critical plasma density. The existence of localized hot electrons is explained on the basis of transit time heating in the resonantly enhanced electric field. The phenomenon provides experimental evidence that the plasma resonance region plays an active role in heating mechanism in low-pressure microwave discharges.