Allowed and forbidden n=2-2 transitions of the elements Ti, Cr, Fe, Co and Ni in Tokamak discharges

Abstract

Wavelengths and transition probabilities are presented for the allowed and forbidden n=2-2 transitions belonging to the fluorine I to lithium I isoelectronic sequences which are expected to be observed in Tokamak discharges. The listing is compiled for the elements Ti, Cr, Fe, Co and Ni, these metals being likely contaminants. The emphasis is placed on an accurate compilation of wavelengths from laboratory and solar-flare observations. Where these are inadequate, predictions are given. In the case of the nitrogen-, carbon- and boron-like intercombination lines, these predictions represent a significant improvement on previous data. Theoretical line intensities calculated for conditions typical of a Tokamak plasma are given for each transition. Identifications in Ti of the five strongest forbidden transitions lying in the visible and near-UV spectral regions have been made in spectra from the DITE Tokamak. Such spectral features are useful diagnostic indicators of metallic ion impurity concentrations and mass motions.