Conductivity of the Plasmas in Electrode Less HID Lamps

Summary form only given. Recently we demonstrated rotating plasma discharges using circularly polarized microwaves in electrodeless high intensity discharge (ELS-HID) lamps, including di-sulfur or InBr vapors. In the design of such lamps, the plasma conductivity is one of the important parameters for optimal coupling of the microwaves and the plasma containing a radiator gas or vapor. The measurement of the plasma conductivity in high pressure HID lamps is difficult because no metallic probe can be inserted in the lamp that is operated at pressures higher than atmospheric pressure in a completely sealed bulb. This paper describes what we call the noninvasive inversion technique to measure the effective plasma conductivity of the radiant plasma exciting the radiator gas or vapor in any electrodeless HID lamps. Using an improved measurement system, we have constructed a number of ELS-HID lamps with excellent microwave-plasma coupling efficiency. We will show some of the results of the photometric characteristics of the lamps constructed using the measured values of the plasma conductivities