Theoretical investigation of electron-ion recombination processes of Li-like tungsten ions

Dielectronic recombination (DR) and radiative recombination (RR) spectra of highly charged Tungsten ions are important for modeling and diagnosing magnetic fusion plasmas. We studied the DR process of Li-like W71+(2s) ions using the flexible atomic code (FAC) based on the relativistic configuration interaction (RCI) method with Breit and QED corrections. The detailed resonance energies, widths and strengths were calculated systematically for the dominated doubly excited states (2p1/2nlj)J(n=19∼29) and (2p3/2n′lj)J(n′=7∼29) of Be-like W70+ ions. The contributions from the higher Rydberg states with n=30∼ncut(ncut=116) are obtained by extrapolation based on the quantum defect theory (QDT). The electron-ion recombination spectra (DR+RR), covering the center-of-mass energy range 0-1700 eV, are presented by taking into account the electron beam temperature at the experimental cooler storage ring (CSRe). It is found that the DR resonances associated with 2s1/2 → 2p1/2 and 2s1/2 → 2p3/2 transitions are not blending for the whole Δn=0 collision energy range, which will provide a good chance for testing fundamental theory clearly by experimental investigation. Finally the plasma rate coefficients are deduced from the calculated recombination spectra in the temperature range from 5.0 × 103 to 1.0 × 108 K. Compared with the AUTOSTUCTURE results, a good agreement is obtained except for the DR rates at the low electron temperature (Te < 5.0 × 105K), which were mainly attributed to the difference of the first resonance group 2p1/219l. The present results will guide the DR experiment of Tungsten ions at the CSRe and also be useful for ITER fusion plasmas modeling.