Floating potential method using a thermionic emissive probe including an ionizing and collisional presheath

Abstract

This article studies the interaction of an argon plasma with an emissive probe considering the effect of both ionization and ion–neutral collisions. The floating potential is determined from the I–V characteristic curves as a function of the probe temperature, neutral gas pressure and plasma electron temperature. This potential increases with increasing probe temperature until reaching the plasma potential, exceeding the saturation value previously indicated by other authors. Finally, a relationship between the plasma electron temperature and the probe temperature at which the floating potential reaches the plasma potential is shown, demonstrating that these probes can be used for diagnosis of the plasma electron temperature.