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A: Fachverband Atomphysik
A 33: Poster Session II
A 33.25: Poster
Mittwoch, 7. März 2018, 16:15–18:15, Redoutensaal
Dielectronic recombination of MNN in highly charged tungsten with open f-shells — •Chintan Shah1, Pedro Amaro2, José Paulo Santos2, and José Ramón Crespo López-Urrutia1 — 1Max-Plank-Institut für Kernphysik, Heidelberg, Germany — 2LIBPhys-UNL, FCT-UNL, P-2829-516, Caparica, Portugal
Tungsten is selected as the coating material for tokamaks Due to its high-resistance to thermal loads. Sputtering leads to contamination of highly-charged W ions in such plasmas where it provides unwanted cooling that can prevent an effective fusion ignition. Thus, an accurate recombination rates are require to predict ionization balance of such plasma [1, 2]. By using an electron beam ion trap (EBIT), we performed measurements of dielectronic recombination following MNN mechanisms in highly charged W in the energy region of multi-electronic compound resonances with many f-holes. In order to probe MNN dielectronic resonances with energies below the ionization threshold of ions with open f-shells, as well as maintaining an ion abundance constant, the electron beam energy was scanned over the resonances with times of tens of milliseconds. Preliminary calculations based on Flexible Atomic Code are reported in order to determine the main MNN resonance channels, ion abundances as well as recombination processes via multi-electron excitations. The present results can be used to provide the experimental benchmark for the theoretical predictions and plasma models [2]. [1] Pütterich et al., Nucl. Fusion 50, 025012 (2010)[2] S. Preval et al., Phys. Rev. A 93, 0420307(2016).