The relative intensities of hydrogen-like fine structure emitted from recombining and steady-state plasmas

Abstract

The ratio of the intensities of the Lyman alpha (n=2 to 1), Balmer alpha (n=3 to 2), Balmer beta (n=4 to 2) and Paschen alpha (n=4 to 3) fine-structure components of hydrogen-like ions emitted from both recombining (ground-state density to 0) and steady-state plasmas of atomic number Z=2, 6 and 12 is examined. Separate account is taken of the (n,l,j) sub-levels up to and including n=5. Ion-induced collisional transitions between sub-levels of the same principal quantum number are considered for the two cases of (i) impurity of atomic number Z emission from a plasma composed mainly of hydrogen and (ii) emission from a plasma composed of full stripped ions of atomic number Z. It is shown that the fine-structure ratios vary from the statistical values and are highly dependent on the electron density and on the ground-state density of the hydrogen-like ion for electron densities below approximately 3*1014 Z8 cm-3 for Lyman alpha, 3*1013 Z8 cm-3 for Balmer alpha and 3*1012 Z8 cm-3 for Balmer beta and Paschen alpha.