THE EFFECTS OF IMPURITY IONS ON THE SCATTERED-LIGHT SPECTRUM OF A PLASMA

Measurement of the scattered light spectrum from hydrogen plasmas containing small amounts of heavy impurity ions confirms the predictions of theory that the low-frequency ion-acoustic scattered light feature consists of the normal profile due to scattering from a pure hydrogen plasma, with a narrow peak superimposed that is attributed to the impurity. The intensity of the impurity peak scales as the square of a mean charge Z*. Measurements are reported for electron densities of 1-3 X 10(18) cm -3 and electron temperatures ranging from 10 to 80 eV.