ABSTRACT
Plasma has characteristic glow, and ‘‘glow’’ associated with glow discharge of gases and vapors is often treated as plasma without recognition that the definition of plasma has to be changed to do so. For instance, the concentration of ions in glow discharge has not been measured simultaneously and independently of the measurement of electron density and calculated based on the assumption of the electroneutrality from data of electron density. Figure 3.7 clearly indicates that the luminous gas phase created by glow discharge of Ar cannot be treated as plasma. If we take a broad meaning of plasma, which is synonymous with luminous gas phase, it becomes necessary to examine physical parameters that control the luminous gas phase. Parameters such as electron temperature, electron density, and associated phenomena such as ionization might not be major parameters that control the luminous gas phase. This situation becomes quite clear when we examine the luminous gas phase created in the glow discharge of organic molecules.
