VOLUMETRIC EMISSION OF ARGON PLASMAS IN THE PRESENCE OF VAPORS OF FE,SI, AND AL

The net volumetric emission was calculated for argon plasmas at atmosp heric pressure in the presence of metal vapors for different elements, over the temperature range from 3000 to 30,000 K. the computations ar e based on the escape factor model, using a semi-empirical method for the determination of line profiles and line broadening effects. Result s for iron, silicon, and aluminum show an important influence of the p resence of even the smallest concentrations of the metal vapors on the net emission coefficient of the plasma. the effect is strongest for i ron, followed by aluminum and silicon. Special attention is given to s elf-absorption effects which are most important in the first millimete r of the optical path of the emitted radiation. The effect is incorpor ated into the calculation procedure of the net emission coefficient an d can be used as a volumetric energy sink as long as the absorption le ngth is shorter than the radius of the control volume used in the comp utation scheme.