Experimental and theoretical studies of the cathode sheath of an argon low pressure hollow cathode discharge

Resumo

This chapter presents the investigations about the characteristics of the cathode sheath generated in an argon low-pressure hollow cathode discharge (HCD). The theoretical model for the cathode sheath is considered to be non-collisional. Secondary electrons emitted from the cathode surface are taken into account in the discharge model and their influence on the theoretical sheath potential profile is investigated. The plasma parameters and the floating potential profile along the discharge axis were inferred from the current-voltage characteristics of a single Langmuir probe positioned at the inter-cathode space of the HCD. For a low pressure HCD, typical values of the electron density and electron temperature are ne ≈ 1016 m-3 and Te = 4 eV, respectively. By using the probe data, the floating potential profile was determined to verify the position of the plasma-cathode sheath interface and to promote a qualitative discussion between theoretical and experimental results. © 2013 by Nova Science Publishers, Inc. All rights reserved.