The merged-beam rate coefficients of dielectronic and trielectronic recombinations (DR and TR) within $\mathrm{\ensuremath{\Delta}}N=0$ channels for Be-like ${\mathrm{Ar}}^{14+}$ were measured by Huang $et\phantom{\rule{4pt}{0ex}}al.$ [Astrophys. J. Supp. Ser. 235, 2 (2018)] at the cooler storage ring in Lanzhou, China. Meanwhile, theoretical data were also calculated with autostructure (AS) code for comparison with the measured resonance spectrum. However, the AS calculations significantly underestimated TR resonance strengths in most cases. In the present work, we find that the electron correlation between DR and TR resonance states with different captured electron principal quantum numbers ($n$) for the captured electrons (multi-$n$ CI) can significantly increase the strength of TR resonances with $n=6$ and 7, which is confirmed through the relativistic distorted-wave (RDW) approximation in the flexible atomic code (FAC) and the semirelativistic distorted-wave (SRDW) approximation in the AS. The corresponding plasma rate coefficients show a significant increase and are in better agreement with the experiment, with differences from the experiment reduced to $\ensuremath{\sim}10%$ in both photoionized plasmas (PP) and collisionally ionized plasmas (CP) temperature ranges, as opposed to the previous theoretical results that exhibited differences of up to $\ensuremath{\sim}30%$ over the same temperature ranges. Taking into account the multi-$n$ CI could account for most of the discrepancy between existing theoretical calculations and experimental results. Understanding electron correlation and its consequences is important for obtaining accurate TR rate coefficients that will be useful for modelers assessing its role in describing non-local thermodynamic equilibrium astrophysical plasma. 

pdf/effect-of-electron-correlation-on-trielectronic-1uhvdmsdua.pdf

Effect of electron correlation on trielectronic-recombination rate coefficients for Be-like argon

High-precision high-voltage detuning system for HIAF-SRing electron target

The experimental study of precision spectroscopy of dielectronic recombination (DR) of highly charged ions is not only important for astronomical plasmas and fusion plasmas, but also can be used as a new precision spectroscopy method to test the strong-field quantum electrodynamic effect, measure isotope shift and extract the radius of atomic nuclei. An specially designed electron beam energy detuning system for electron-ion recombination precision spectroscopy experiments has been installed at the heavy ion storage ring CSRe in Lanzhou, where the electron-ion collision energy under the center-of-mass system can be detuned to 1 keV, and an independently-developed plastic scintillator detector and multiwire proportional chamber detector have been installed downstream of the electron cooler of the CSRe for the detection of recombined ions. The multiwire proportional chamber detector has the ability to non-destructively monitor the profile of the ion beam in real-time while acquiring the recombined ion counts, providing guidance for optimization of the ion beam. On this basis, the first test experiment of dielectronic recombination of Kr25+ ions has been carried out at the CSRe, and the dielectronic recombination rate coefficients in the range of 0-70 eV at the frame of center-of-mass were measured. In order to fully understand the experimental results, we calculated the dielectronic recombination rate coefficients of the Kr25+ ion using the Flexible Atomic Code (FAC) and made a detailed comparison with the experiment, which is in good agreement, and only the resonance energies of the two resonance peaks at 1.695 eV and 2.573 eV are significantly different. In addition, the DR resonance energies and intensities were obtained by fitting the experimental results in the range 0-35 eV, and we found that the transition 3s→4l (∆n=1) contributes significantly to the experimental spectral lines. Furthermore, we compare the plasma rate coefficients derived from the DR rate coefficients with those derived from the AUTOSTRUCTURE and FAC theories, which differ by 20 percent in the temperature range less than 106 K. The experimental results show that the DR experimental platform of the CSRe has very good stability and reproducibility, and can provide support for the future DR experiments of highly charged ion, i.e. for testing strong-field quantum electrodynamics effect and measuring the properties of atomic nuclei.

Dielectronic recombination experiment of Na-like Kr25+ at the heavy ion storage ring CSRe

Abstract Dielectronic recombination (DR) rate coefficients for C-like Ca 14+ were measured by Wen et al. at the electron cooler storage ring in Lanzhou, China. The measured DR rate coefficients from 0 to 92 eV cover most of the DR resonances associated with the 2 s 2 2 p 2 → 2 s 2 2 p 2 and 2 s 2 2 p 2 → 2 s 2 p 3 core transitions. In addition, Wen et al. reported theoretical results calculated with the Flexible Atomic Code (FAC) and AUTOSTRUCTURE (AS). However, these theoretical results show widespread and significant differences from the measured DR spectrum in both resonance energies and strengths, as well as between each other. In the present work, we uncover the reasons behind these large differences, both theoretical and experimental. The new FAC and AS results reproduce the observed spectrum in detail, especially at resonance energies below 8 eV, and they are in very close agreement with each other. The present plasma rate coefficients agree with the experimentally determined values to within 20% and 2% in the photoionized plasma (PP) and collisional ionized plasma (CP) temperature ranges, respectively. This is in contrast to the previous theoretical results, which showed differences with the experiment of up to ∼40% over the PP temperature range. The present FAC and AS results agree with each other within 5% in the PP and CP temperature ranges. Thus, the theoretical uncertainty is greatly reduced for the DR of Ca 14+ and the present benchmarking with the experiment gives confidence to data users modeling non–local thermodynamic equilibrium plasma. 

Benchmarking Dielectronic Recombination Rate Coefficients for Carbon-like Ca14+

Dielectronic-Recombination (DR) experiments of highly charged ions are performed in the main Cooler Storage Ring (CSRm) at Heavy Ion Research Facility in Lanzhou (HIRFL) accelerator complex. A new detuning power system of the electron cooler is developed to modulate the electron velocity from the cooling velocity and thus control the collision energy in the experiment. In this paper, the design and commissioning of the detuning power system are reported. The detuning power supply adopts the scheme of HVDC (high-voltage DC) and HVA (high-voltage amplifier) connected in series. A FPGA digital controller combined with a high-precision ADC/DAC board is used for multiple-linear voltage settings and feedback. The output maximum DC voltage is −5 kV and the detuning voltage is in the range of 0 to ±1 kV. The main features are the good output voltage stability of 10 ppm and the rapid voltage changing of 10 V/μs. The decoupling and protection of the detuning power supply under the high detuning pulse current are described as well. Finally, a DR spectrum of Ar15+ ions measured with the new detuning power system is presented. The experimental result shows a good resolution, verifying the reliability and feasibility of the design. 

High-voltage detuning power system of HIRFL-CSRm electron cooler for Dielectronic-Recombination experiments

Dielectronic recombination (DR) rate coefficients for carbon-like Kr30+ have been measured over the collision energy of 0–60 eV using the heavy-ion storage ring CSRe at the Institute of Modern Physics in Lanzhou, China. The present DR spectrum covers the resonances associated with the 2s22p2[3P0]→2s22p2[3P1,2] , 2s2p3 and 2p4 (Δn=0) core excitations. The corresponding DR resonance energies and strengths have been calculated by using the flexible atomic code (FAC) to understand the measured results. An overall agreement has been obtained between the experiment and theory, except for the data at the collision energies below 7 eV and in 35–38 eV, where the electronic correlation effect is strong. In particular, the resonances from the trielectronic recombination due to 2s22p2+e−→2p4[1D2]6l have been identified with the help of the FAC calculation. Temperature-dependent plasma recombination rate coefficients were derived from the measured DR rate coefficients for the temperature range 103–107 K and compared with our FAC calculations as well as the previous AUTOSTRUCTURE calculations by Zatsarinny et al (2004 Astron. Astrophys. 417 1173–81). The FAC and AUTOSTRUCTURE calculations are in good agreement with the presently derived plasma rate coefficients. The present work provides the benchmark data for astrophysical and laboratory plasma modeling.

Dielectronic recombination rate coefficients of carbon-like Kr30+

This paper introduces the technical scheme of the HIAF-SRing (High Intensity heavy-ion Accelerator Facility-Spectrometer Ring) electron cooling 15-stage −600 kV high-voltage power supply system. The main auxiliary power supply of the power system adopts the LCC resonant converter to work in the soft-switching state of DCM, and uses the post-stage LC filter to output high-frequency sinusoidal waves to provide low-harmonic high-frequency power and protection under extreme conditions for the 15-stage electronic cooling power supply. High-voltage isolation power transmission adopts high-frequency isolation transformer, and the 15-stage inter-stage transformer has the same phase and low loss power transmission by designing resonance compensation capacitors. Each stage of 40 kV high voltage output adopts the series output mode of ±20 kV power supply modules, and the reference voltage of the 24 bit-DAC extended outside the FPGA is compared with the feedback voltage of the designed high-precision high-voltage divider with temperature control to achieve high-precision feedback control of each stage. At present, the 22 kHz high frequency sinusoidal soft-switching output of the main auxiliary power supply, the phase compensation calculation and test of the three-stage isolation transformer, and the high precision feedback control of the single-stage −40 kV power supply have been completed. Through the design of 50Hz ~ 10MHz bandwidth C-R measurement circuit, the full power ripple of single-stage −40kV power supply with high-frequency power transmission is tested, and the results show that it can meet the requirements of electron cooling experiment.

The Precision −600 kV High Voltage Power Supply System for the HIAF-SRing Electron Cooler

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of {limit} columns in the table. Remove at least 1 column to add or create another one.

Yunbin Zhou

Author Tools

Chat about Author

Papers

High-voltage detuning power system of HIRFL-CSRm electron cooler for Dielectronic-Recombination experiments

Dielectronic recombination rate coefficients of carbon-like Kr30+

The Precision −600 kV High Voltage Power Supply System for the HIAF-SRing Electron Cooler