High-energy electrons near the dielectric-plasma boundary in a large-area surface-wave plasma excited at 915 MHz

Abstract

High-energy electrons produced in a planar ultrahigh frequency surface-wave plasma excited at 915 MHz have been studied using the Druyvesteyn technique of Langmuir probe measurements. Near the dielectric-plasma boundary, the hump of energetic electrons was clearly observed in the electron energy probability functions. The hump steeply shifted its center energy from about 20 eV at z=0.2 cm to almost zero at z∼1.4 cm apart from the quartz window, while the bulk electrons were strongly heated there. Peak energy and width of the hump seemed to have a strong spatial correlation with the electric field intensities.