Studies on electron energy and discharge characteristics of DC plasmas

Abstract

There has been wide spread use of the weakly ionized DC discharge in basic plasma studies as well as in material processings. The plasma parameters in such discharges are significant for understanding the basic plasma phenomena in different plasma based applications. The electron temperature (electron average energy), one of the important plasma parameters, has a profound effect for creation of active species, which plays a dominant role in different plasma based processes. In order to understand the properties of the diffused plasma produced by local ionization of the neutral molecules in the target section of a Double Plasma device, the studies on the electron energies are essential. This thesis presents the studies on the electron energy and the discharge characteristics of DC plasmas. The experimental observations are carried out in two different experimental devices. Three different sets of experiments are carried out in a Double Plasma Device to study the electron energy effect on the diffused plasma parameters as well as to control the plasma parameters by two different mechanical techniques. In another set of experiment the plasma property and discharge characteristics of a DC pulsed plasma has been studied by using different diagnostic probes. The thesis comprises of six chapters containing four different set of experiments. The research problems included in the thesis are: i) Studies on the role of the high energetic electron in controlling the diffused plasma parameters of a Double Plasma Device. ii) Development of mechanical techniques to control the plasma parameters. iii) Studies on the plasma properties and the discharge characteristics of a DC pulsed plasma. The brief description on each individual chapter are presented hereafter. Chapter 1 is the introductory chapter, which includes a general introduction to the space and laboratory plasmas. Then discussions on the plasma parameters and different plasma phenomena is presented. This chapter also contains a brief introduction to the two different...