Plasma conditions in a moly-oxide electrodeless bulb discharge

Summary form only given, as follows. Due to the hazardous material designation of spent fluorescent lamps on board naval vessels, the Naval Research Laboratory has been investigating alternative lighting concepts which are free of mercury. Previous work (ICOPS ´00) on an electrodeless moly-oxide discharge for lighting applications investigated the plasma and emission properties of a cylindrical tube containing a flowing mixture of argon and oxygen and an axial Mo wire. We have upgraded the configuration to a quartz bulb filled with /spl sim/1 Torr Ar, excited by an external RF coil at 13 MHz, and introduced the metal as a MoO/sub 3/ powder. Plasma conditions are investigated using microwave interferometry for the electron density (10/sup 13/-10/sup 14/ cm/sup -3/); near IR emission line spectroscopy for the electron temperature (1.1-1.4 eV); and absolute spectroscopy for the visible luminous flux (/spl sim/3000 lumens). Analysis with a Boltzmann code given the above conditions and a simple atomic model for Mo provides an estimate of its density (10/sup 12/-10/sup 13/ cm). Compositional effects and approaches to improving the output will be discussed.