O-shell emission of heavy atoms in an optically thin tokamak plasma

Heavy atoms Au ({ital Z}=79), Pb ({ital Z}=82), Bi ({ital Z}=83), and U ({ital Z}=92) have been introduced in the low-density ({ital n}{sub {ital e}}{similar to}10{sup 13} cm{sup {minus}3}) high-temperature ({ital T}{sub {ital e}}{ge}1 keV) TEXT tokamak (Fusion Research Center, University of Texas at Austin) plasma. The emission has been measured in the 50--200-A range using a photometrically calibrated, time-resolving grazing-incidence spectrometer. The {ital O}-shell ion emission has been identified by comparison with {ital ab} {ital initio} energy-level calculations and line-intensity predictions of collisional radiative models for various charge states with 5{ital p}{sup 6}5{ital d}{sup {ital k}} ground-state configurations.