The spectrum of highly ionized praseodymium and dysprosium from the Texas tokamak plasma in the 50–250-Å range

Abstract

Spectra of highly ionized praseodymium and dysprosium recorded from the Texas tokamak (TEXT) plasma have been analyzed in the 50–250-Å range. The spectra contain high-intensity continuum bands in the region below 100 Å and bright individual lines above this wavelength. Lines of highly ionized praseodymium and dysprosium have been identified. The highest ionization state reached in the 1-keV central electron temperature tokamak plasma was Cu i-like Pr xxxi. The composition of the bands is explained in terms of a new theoretical approach developed to treat large unresolved transition arrays. The brightness of the continuum is compared with that of intense spectral lines emitted in the same wavelength range.