Dielectronic recombination of xenonlike tungsten ions

Abstract

Dielectronic recombination (DR) of xenonlike W20+ forming W 19+ has been studied in the collision energy range 0-140 eV. The measured rate coefficient is dominated by strong DR resonances even at the lowest experimental energies. At temperatures relevant for fusion plasmas, the experimentally derived plasma recombination rate coefficient is over a factor of 4 larger than the theoretically-calculated rate coefficient which is currently used in fusion plasma modeling. The largest part of this discrepancy stems most probably from the neglect in the theoretical calculations of DR associated with fine-structure excitations of the W20+([Kr]4d10 4f 8) ion core.