Radiation calculation in electroded and microwave HID lamps

Summary form only given. Advances in microwave and light source technology in the last decade have led to the most recent generation of highly efficient electrodeless discharge lamps^1,2. Such lamps are generally classified in the scientific literature as electrodeless HID (EHID) lamps, but currently they are often referred to as plasma lamps. The differences in radiation between discharges containing electrodes and discharges sustained by a microwave (mw) electromagnetic field are discussed. Microwave lamps are considered to be more efficient than their electroded counterparts in converting electric power to radiation at increased values of electrical power, provided that all other parameters of the lamp are kept unchanged. The temperature profile in an electroded discharge is experimentally measured while the temperature profile for a microwave discharge is computed from a 1D power balance model. The microwave discharge is assumed to be in TM₀₁₀ mode and sustained by a microwave field of frequency 2.45 GHz. The plasma under study is considered to be at Local Thermodynamic Equilibrium (LTE) and the resulting total line profile for each visible and UV line is obtained by the convolution of a Lorentzian and a quasi-static profile. The net emission coefficient (NEC) of an electroded discharge is calculated by using a model based on ray-tracing method. The obtained NEC is used by another numerical model based on power balance equation in order to obtain the temperature profile for the microwave discharge. The ray-tracing method is again em ployed to simulate the radiation transport in the microwave discharge. The output flux, luminous flux, luminous efficacy, the correlated color temperature, the chromaticity coordinates and photometric curves of these lamps were then obtained and compared.