Accuracy of K-shell spectra modeling in high-density plasmas

We present spectroscopic measurements of the helium-like and lithium-like a rgon emission supported by Thomson scattering diagnostics on gas bag target s. These data provide critical tests of plasma spectroscopic K-shell models . In particular, we have measured the line radiation in the wavelength regi on of the He-like Ar 1s(2)-1s3l transition (He-beta) that is of interest fo r density and temperature measurements of plasmas from gas-filled targets ( n(e)less than or equal to 10(21) cm(-3)), laser ablation targets (n(e)less than or equal to 10(22) cm(-3)), and inertial confinement fusion capsule im plosions (n(e)greater than or equal to 10(24) cm(-3)). The spectra show lit hium-like dielectronic satellites on the red wing of the He-beta line that are temperature sensitive and are known to influence the shape of the Stark -broadened line profiles observed from implosions. To examine the kinetics modeling of this complex, i.e., the He-beta and its associated satellites, we have performed experiments in gas bag plasmas at densities of (0.6-1.1) x 10(21) cm(-3) where we independently determine the electron temperature w ith ultraviolet Thomson scattering. The comparison of the satellite intensi ties with kinetics modeling shows good agreement for satellites whose upper states are populated by dielectronic capture, but shows discrepancies for inner-shell collisional excited transitions.