Recombination of W18+ ions with electrons: Absolute rate coefficients from a storage-ring experiment and from theoretical calculations

Abstract

We present new experimentally measured and theoretically calculated rate coefficients for the electron-ion recombination of W${}^{18+}$([Kr] $4d^{10}$ $4f^{10}$) forming W${}^{17+}$. At low electron-ion collision energies, the merged-beam rate coefficient is dominated by strong, mutually overlapping, recombination resonances. In the temperature range where the fractional abundance of W${}^{18+}$ is expected to peak in a fusion plasma, the experimentally derived Maxwellian recombination rate coefficient is 5 to 10 times larger than that which is currently recommended for plasma modeling. The complexity of the atomic structure of the open-$4f$-system under study makes the theoretical calculations extremely demanding. Nevertheless, the results of new Breit-Wigner partitioned dielectronic recombination calculations agree reasonably well with the experimental findings. This also gives confidence in the ability of the theory to generate sufficiently accurate atomic data for the plasma modeling of other complex ions.

11 pages, 4 figures, 2 tables, 40 references, accepted for publication in Physical Review A

References in corpus (3)

• Dielectronic recombination of xenonlike tungsten ions
• Dielectronic recombination of Fe^{13+}: benchmarking the M-shell
• Electron-ion Recombination of Fe XII forming Fe XI: Laboratory Measurements and Theoretical Calculations

Cited by in corpus (6)

• Photoionization of ions with synchrotron radiation: From ions in space to atoms in cages
• Electron-ion merged-beam experiments at heavy-ion storage rings
• Coherent and stochastic contributions of compound resonances in atomic processes: Electron recombination, photoionization and scattering
• Electron-impact single ionisation of W${}^{q+}$ ions: Experiment and theory for $11\le \mathbf{q}\le 18$
• Recombination of open-f-shell tungsten ions
• Dielectronic resonances of LMn and LNn (n $\ge$ 4) series in highly-charged M-shell tungsten ions