Development Of An Experimental Database Of Euv Spectra From Highly Charged Ions Of Medium To High Z Elements In The Large Helical Device Plasmas

We are developing an experimental database of extreme ultraviolet spectra from highly charged ions using optically thin high-temperature plasmas produced in the Large Helical Device. Spectra from a variety of elements with atomic numbers ranging from 36 to 83 have been systematically recorded in the range of 1-20 nm by a grazing incidence spectrometer. For higher Z elements from tin onward, discrete or quasicontinuum spectral features from n=4 (N-shell) ions are mainly observed depending upon the plasma temperature, which leads to some new experimental identifications of spectral lines. On the other hand, major emitters are n=3 (M-shell) ions for medium Z elements from krypton to ruthenium. The calculated wavelengths for Delta n not equal 0 transitions agree well with the measurements and the calculated wavelengths are systematically shifted to shorter wavelengths for Delta n=0 transitions associated with inner-subshell excited configurations.