Electron-impact excitation cross-section measurements at EBITs from 1986 to 2006

Chen, Hui; Beiersdörfer, P.

doi:10.1139/p07-152

Cited by 19 publications

(22 citation statements)

References 75 publications

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“…In the following measurements this effect was accounted for, and high-purity Ge detectors, and microcalorimeters, as well as, crystal spectrometers were used (see e.g. Chen & Beiersdorfer 2008). As σ RR is much smaller than σ EIE , approximately one RR photon is observed for 100-1000 photons in the EIE lines.…”

Section: Resultsmentioning

confidence: 99%

Recombination and Electron Impact Excitation Rate Coefficients for S Xv and S Xvi

Mahmood

Ali

Orbán

et al. 2012

ApJ

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Recombination and electron impact excitation of S 14+ and S 15+ ions was measured at the Stockholm refrigerated electron beam ion trap. The collision energy range was 1.4-3 keV, where we covered the KLL, KLM, KLN, and KLO dielectronic recombination resonances resulting in S 13+ and S 14+ ions. The recombination rates were obtained by detecting the charge state distribution with a newly developed time-of-flight technique. Resonance energies and cross sections calculated within the relativistic many-body perturbation theory for S 15+ agree well with the experimental data. The temperature dependent rate coefficients have been extracted from the measured rates and compared with calculations from literature used for studies of collisionally ionized astrophysical plasmas. A good agreement for S 15+ was obtained, while the plasma rates for S 14+ were 23 % lower than the so far published values. In addition to the time-of-flight spectra, the x-ray spectra, produced mainly by photo-recombination and excitation, have been also collected. The combination of these two measurements allowed us to separate the photo-recombination and the excitation spectra, and the excitation rate coefficients for summed intensities with known fractions of S 14+ and S 15+ ions were extracted.

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Section: Resultsmentioning

confidence: 99%

Recombination and Electron Impact Excitation Rate Coefficients for S Xv and S Xvi

Mahmood

Ali

Orbán

et al. 2012

ApJ

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“…To our knowledge, electron impact excitation experimental measurements are rare (Chen & Beiersdorfer 2008). Chantrenne et al (1992) obtained the measurement of electron impact excitation cross sections as a function of energy for w, x, y, and z lines of Ti 20+ .…”

Section: Comparison With Experimental Observationsmentioning

confidence: 99%

Electron impact excitation for He-like ions withZ= 20–42

Wang

et al. 2017

A&A

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Aims. Spectral lines of He-like ions are among the most prominent features in X-ray spectra from a large variety of astrophysical and high-temperature fusion plasmas. A reliable plasma modeling and interpretation of the spectra require a large amount of accurate atomic data related to various physical processes. In this paper, we focus on the electron-impact excitation (EIE) process. Methods. We adopted the independent process and isolated resonances approximation using distorted waves (IPIRDW). Resonant stabilizing transitions and decays to lower-lying autoionizing levels from the resonances are included as radiative damping. To verify the applicability of the IPIRDW approximation, an independent Dirac R-matrix calculation was also performed. The two sets of results show excellent agreement. Results. We report electron impact excitation collision strengths for transitions among the lowest 49 levels of the 1snl(n ≤ 5, l ≤ (n − 1)) configurations in He-like ions with 20 ≤ Z ≤ 42. The line ratios R and G are calculated for Fe XXV and Kr XXXV. Conclusions. Compared to previous theoretical calculations, our IPIRDW calculation treats resonance excitation and radiative damping effects more comprehensively, and the resulting line emission cross sections show good agreement with the experimental observations. Our results should facilitate the modeling and diagnostics of various astrophysical and laboratory plasmas.

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“…The use of a mcirocalorimeter for studying the emission of tungsten and gold plasmas is now well established by numerous measurements. These measurements include the identification and energy determinations of tungsten and gold transitions [38e40], excitation cross-section measurements [41,42], development of plasma diagnostics [43e45], as well as ionization balance determinations [46e48]. The combination of the electron beam ion trap method for creating the ionization balance at predetermined electron temperatures and a high-resolution microcalorimeter for recording the dielectronic recombination photons can, thus, in the future provide a platform for highlighting the critical physics in properly calculating the ionization balance.…”

Section: The Need For Differential Ionization Balance Measurements Anmentioning

confidence: 99%

Atomic physics and ionization balance of high-Z Ions: Critical ingredients for characterizing and understanding high-temperature plasmas

Beiersdörfer¹,

May²,

Scofield³

et al. 2012

High Energy Density Physics

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Electron-impact excitation cross-section measurements at EBITs from 1986 to 2006

Cited by 19 publications

References 75 publications

Recombination and Electron Impact Excitation Rate Coefficients for S Xv and S Xvi

Recombination and Electron Impact Excitation Rate Coefficients for S Xv and S Xvi

Electron impact excitation for He-like ions withZ= 20–42

Atomic physics and ionization balance of high-Z Ions: Critical ingredients for characterizing and understanding high-temperature plasmas

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