Recombination of open-f-shell tungsten ions. (10th February 2017)

• Record Type: Journal Article
• Authors: Krantz, C; Badnell, N R; Müller, A; Schippers, S; Wolf, A
• Is Part Of: Journal of physics. Volume 50:Number 5(2017:Mar. 01)
• Publication Date: 2017-02-10
• Subjects: recombination -- tungsten -- plasma; Atoms -- Periodicals; Molecules -- Periodicals; Optics -- Periodicals; Nuclear physics -- Periodicals; 539.6
• DOI: 10.1088/1361-6455/aa547d
• Languages: English
• ISSNs: 0953-4075

Abstract

Abstract: We review experimental and theoretical efforts aimed at a detailed understanding of the recombination of electrons with highly charged tungsten ions characterised by an open 4 f sub-shell. Highly charged tungsten occurs as a plasma contaminant in ITER-like tokamak experiments, where it acts as an unwanted cooling agent. Modelling of the charge state populations in a plasma requires reliable thermal rate coefficients for charge-changing electron collisions. The electron recombination of medium-charged tungsten species with open 4 f sub-shells is especially challenging to compute reliably. Storage-ring experiments have been conducted that yielded recombination rate coefficients at high energy resolution and well-understood systematics. Significant deviations compared to simplified, but prevalent, computational models have been found. A new class of ab initio numerical calculations has been developed that provides reliable predictions of the total plasma recombination rate coefficients for these ions.