Measurements of Plasma Parameters in α High-Frequency Glow Discharge Using the Orifice Probe

Abstract

The electron temperature and the sheath potential in the plasma of radio-frequency glow discharge are measured by extracting the charged particles through a hole in a platinum and glass probe which was set on the wall of the discharge tube and by subjecting the effused particles to a retarding electric field. The observed electron field. The observed electron translational energy distribution is found to fit the Maxwellian distribution function. The electron temperature and the sheath potential increase with decreasing pressure. Addition of small amount of argon to helium results in a steep decreas of the electron temperature and the sheath potential. The electron temperature is kept nearly constant when the content of argon exceeds 10%. The lower values of the electron temperature obtained for polyatomic molecules are conjectured to be related with large cross sections for the energy exchange between plasma electrons and the relevant vibrational levels of molecules.