Effect of light scattering by macroscopic particles on spectral line contours

The effect of scattering macroscopic particles on spectral line contours of alkali atoms in a plasma of combustion products is investigated experimentally. The effect on line contours of short exposure of a volume irradiate by an external radiative source is investigated. An optical scheme imitating short exposure, often encountered in diagnostics of experiments, is developed. The experiments were carried out with anisotropically scattering $\rm Al_2\rm O_3$ particles, whose optical density did not exceed $0.15$. It is shown that the particles used do not affect substantially the line contours in the absence of an external radiative source. Light from external sources, scattered by particles, affects the line contours. If the line is optically thin at the center, it is distorted only at the tails. Relations are obtained, making it possible to describe the observed effects qualitatively. The results must be taken into account primarily in using spectral diagnostics of media with macroscopic particles (a plasma in near-electrode regions of high-power discharge, MHD currents, etc.).