Microwave “resonance” discharge as a source of UV radiation

Results of theoretical and experimental research of excited in a Ar+Hg mixture microwave discharge as a source of optical radiation are presented. Much attention is given to a low pressures when "resonance" version of discharge, properties of which are prescribed by nonlinear processes developed near the plasma resonance (region where Langmuir plasma frequency is equal to the cyclic frequency of microwave radiation), is realized. Under the "resonance" conditions decreasing of pressure leads to the strong increasing of intensity of Hg radiation (including the biologically active UV) and to the fast diminishing of Ar lines radiation. Collisional-radiative model (CPM) of microwave discharge plasma based on a detail analysis of kinetics of population of excited states of Hg and Ar atoms has been developed. When behavior of calculated characteristics has been compared with the measured once qualitative verification of resonance effect of microwave energy absorption by discharge plasma has been received. Calculation performed in a framework of kinetic model describing population and depopulation of electron-excited states of Hg and Ar demonstrate a good correlation with the experimental results. Experimental and theoretical data have been used as the basis of discussing in this work construction of powerful microwave UV lamp.