Abstract
Simultaneous resonant scattering of Lyman and Balmer radiation in low-density (Ne≲ 1014 cm-3) Hydrogen plasmas has been examined. The equations governing the rates of population of the first few excited levels are solved in the case of intense pumping. Parameters are obtained which relate the total atomic or molecular density to the population density in the third level and thus also to the intensity of the first Balmer line which is easy to measure experimentally. A possible means of obtaining sufficient UV power for this method is also discussed.