Low energy range dielectronic recombination of Fluorine-like Fe ¹⁷⁺ at the CSRm

Abstract

The accuracy of dielectronic recombination (DR) data for astrophysics related ions plays a key role in astrophysical plasma modeling. The measurement of the absolute DR rate coefficient of Fe 17+ ions was performed at the main cooler storage ring at Institute of Modern Physics, Lanzhou, China. The experimental electron-ion collision energy range covers first Rydberg series up to n = 24 for the DR resonances associated with the 2 P1/2 → 2 P3/2 ∆n = 0 core excitations. A theoretical calculation was performed by using FAC code and compared with the measured DR rate coefficient. Overall reasonable agreement was found between the experimental results and calculations. Moreover, plasma rate coefficient was deduced from the experimental DR rate coefficient and compared with the available results from the literature. At the low energy range significant discrepancies were found therein and the measured resonances challenged state-of-the-art theory at the low collision energies.

Enhancement of electron–ion recombination rates at low energy range in the heavy ion storage ring CSRm*

“…The main features of the experimental technique were described in the previous papers and Refs. [26][27][28]. Here we will just briefly describe the general experimental method and important parameters related to the present work.…”

Atomic structure and collision dynamics with highly charged ions

“…The DR experimental method at the CSRm has been already described in detail elsewhere. [38][39][40] In order to perform DR experiments with high-Z HCIs, the electron cooler (EC-300) at the CSRe has been upgraded with an embedded electron energy fast detuning system for the merged-beams electron-ion collision experiments. A plastic scintillation detector (PSD) and a multiwire proportional chamber (MWPC) detector have been developed and installed downstream of the electron cooler to detect the recombined and ionized ions in the electron-ion collision experiments at the CSRe.…”

“…In the case of TR, the capture is associated with the excitation of two core electrons to excited levels and is completed when the triply-excited intermediate level decays by photoemission. The experimental DR spectra of Be-like 40 Ar 14+ and theoretical calculations from the AUTOSTRUCTURE code are compared as shown in Fig. 4.…”

“…In addition to the investigation of the QED effect and Breit interaction, HCIs have been proposed to enable sensitive tests of physics beyond the standard model and the realization of high-accuracy atomic clocks, owing to their high sensitivity to fundamental physics and insensitivity to external perturbations. [99] Very recently, the Coulomb crystallization of B-like 40 Ar 13+ has been realized in a cryogenic linear radiofrequency trap by means of sympathetic cooling through Coulomb interaction with a directly laser-cooled ensemble of Be + ions. [100] Furthermore, coherent laser spectroscopy of highly charged 40 Ar 13+ ions has been achieved using the quantum logic technique, and the determined absolute frequency of the 40 Ar 13+ fine-structure transition reached an uncertainty of 3 × 10 −15 , which pave the way for future HCI clock investigation and applications.…”

Absolute dielectronic recombination rate coefficients of highly charged ions at the storage ring CSRm and CSRe

“…More recently, the main cooler storage ring (CSRm) and the experimental cooler storage ring (CSRe) at the Heavy Ion Research Facility in Lanzhou (HIRFL) started contributing DR rate coefficients for HCIs. Recombination experiments with 36 Ar 15+ , 40 Ar 12+,13+,14+,15+ , 40 Ca 14+,16+,17+ , 56 Fe 17+ , 58 Ni 19+ , and 76 Kr 25+ ions [20][21][22][23][24][25][26][27][28][29] have been accomplished at the CSRm in the past few years, and the first calibration experiment with Na-like Kr 25+ ions has been successfully performed at the CSRe. [30] In this paper, the recent progress on DR experiments at the HIRFL-CSRm and CSRe is overviewed.…”