Observation of H- and He-like X-Ray Line Emission in High-Density Tokamak Plasmas

Characteristic x-ray spectra of plasma impurity ions have been measured in the region λ=4.3-5.1 {}. The observation of strong principal $n=2$ to $n=1$ x-ray lines for H-like sulfur and for He-like sulfur and chlorine in the density range (1-6) ×{} 10¹⁴ cm^-3 is reported. Dielectric recombination and inner-shell excitation satellite lines are weak. The results, which are of interest for both atomic physics and plasma diagnostic applications, are compared with atomic calculations of line spectra and transition rates.