Spectral Radiation Of The Resonator Coupled Microwave Plasma

Lighting consuming the total electricity consumption of a country vary from 15 % to 25% . With the increasing consciousness of environment—protecting and energy—saving, people pay more attention on the research of energy—saving and environment—protecting in lighting. The microwave light sources become one of the research highlights for their long lives and high efficacy. In the study of microwave light sources, the spectrum radiation plays an important role in it. The produce and maintain mechanism of the discharge can be released with the study of the radiation. The condition for spectrum radiation of the plasma can be obtained by different incident power experiments and simulations. Then the design parameters for high efficacy can be derived, and the optimum design for different condition can realized.The temperature profile of the plasma is important for spectrum radiation study. The temperature profiles of microwave sulfur plasma have been measured with Boltzmann slope method. And the maximum temperature point doesn't locate in the center of the plasma. The higher incident microwave power, the farther of the maximum point to the center. The Elenbaas—Heller energy balance equation can be calculated by iteration procedure and Joule heating couple equation. The temperature profile of the plasma can be simulated. It is found that in high pressure plasma the microwave energy is deposit in the surface layer near the wall, and the energy is pass inside the plasma with collisions and excitations among particles. Comparing the simulations with experiments, the trends are the same, but the simulated values are about 700K low.Based on the calculated temperature profile the spectrum of microwave sulfur plasma can be simulated. With the radiation transfer equation and line—broaden theory the simulated spectrum is with good agreement with experiment. The bulb diameter and sulfur dosage for the optimum radiation of the microwave sulfur plasma have been searched under different incident power via simulation. The results are with good agreement with experiments. The diameter of the bulb is reduced nearly linearly with power, and the sulfur dosage is change much slower. The system efficacy can be improved via this design. The possibilities of other emitting materials used in resonant cavity couple microwave lamp have been studied. The InBr has been stress on the study of improve the color rendering performance, the feasibility and consideration for InBr used in microwave lamp have been put forward. In addition other materials have been tried in the microwave lamp.At last the start—up processes of the resonant cavity coupled plasmas have been studied. The breakdown and warm—up have been studied with different gases. And the start—up performance of the buffer gases has been analyzed. To minimize the impact of microwave energy on lamp components, the start—up process should as quick as possible. It has been found that easy breakdown doesn't mean quick start—up. The high incident power can shorten the star—up time. The ⁸⁵Kr can be used as buffer gas in microwave lamp. And it can get better start—up performance with the dosage of 30 torr. The start—up time can reduce 20s, and the reflect power can reduce more than 50%. Other factors influencing the start—up process have also been experimentally analyzed. The optimum start—up parameters for microwave plasma have been obtained.