Updating of atomic data needed for ionization balance evaluations of krypton and molybdenum

Abstract

Atomic data for both ionization and recombination of Kr and Mo ions are reviewed, the rates for these processes needing to be regularly updated following the publication of new theoretical calculations and new experimental data. Kr is used in magnetic-confinement fusion devices to produce a peripheral radiating mantle meant to spread the heat load on the plasma-facing components. In a few tokamaks Mo tiles cover the plasma-facing surfaces, acting in most cases as a plasma-column limiter. The collected atomic data represent the state of the art on the ionization and recombination data for the two considered elements. Samples of rates are proposed for both ionization and recombination along with tables of the fractional abundances at ionization equilibrium. The proposed rates should be included in codes that simulate the impurity behaviour in magnetic-confinement fusion devices, i.e., when radial transport is added to ionization and recombination to predict spatially resolved charge-state distributions to be compared with experimental results. As an example, the simulation of a Mo laser blow-off injection on the JET tokamak is re-analysed with the revised rates and multiplicative correction factors are obtained for the rate ratios recombination over ionization for L-shell ions.