Dielectronic Satellite Spectrum of Heliumlike Iron (Fe XXV)

Bitter, M.; Hill, K. W.; Sauthoff, N.; Efthimion, P. C.; Meservey, E.; Roney, W.; Goeler, S. von; Horton, Robert; Goldman, M.; Stodiek, W.

doi:10.1103/physrevlett.43.129

Cited by 166 publications

(48 citation statements)

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“…1͒. The spectra provide measurements of the central ion temperature, [3][4][5] central electron temperature, 6 central toroidal rotation, and distribution of the highly ionized charge states of argon, which in combination with other diagnostics can be used to study impurity transport. 7 Spectra of helium-like argon have previously been observed at the Tokamak Fontenay aux Roses ͑TFR͒ 8,9 and at the Alto Campo Torus ͑ALCATOR͒ tokamaks, where they are being used for the routine diagnostic purposes.…”

Section: Introductionmentioning

confidence: 99%

High-resolution x-ray crystal spectrometer/polarimeter at torus experiment for technology oriented research-94

Weinheimer

Ahmad

Herzog

et al. 2001

Review of Scientific Instruments

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A high-resolution x-ray polarimeter has been installed at the torus experiment for technology oriented research ͑TEXTOR-94͒. The instrument consists of two spectrometers in Johann geometry, utilizing the dependence of Bragg reflection on the polarization. The dispersion plane of the so-called horizontal spectrometer coincides with the midplane of the tokamak, whereas the dispersion plane of the so-called vertical spectrometer lies perpendicular to the midplane of the tokamak. Both spectrometers operate with cylindrically bent quartz crystals of dimensions 153 mmϫ38 mmϫ0.7 mm with a 2d spacing of 4.9130 Å. The radii of curvature of the horizontal and vertical spectrometer crystals are 3820 mm and 4630 mm, respectively. The detectors are multiwire proportional counters having a large entrance window of 180 mmϫ90 mm, with a high count rate capability of up to 2.5ϫ10 5 photons/s, and a spatial resolution of 0.4-0.65 mm, depending on the count rate. The unique data acquisition system makes it possible to record up to 8192 spectra per TEXTOR-94 discharge to study fast events and impurity transport. The instruments are sensitive to spurious amounts of argon in hydrogen or deuterium discharges and aim for x-ray polarization measurements and other core plasma diagnostics like electron temperature, ion temperature, plasma rotation, impurity transport, and relative abundance of Ar 15ϩ /Ar 16ϩ . The first measurements of toroidal rotation speed, ion and electron temperatures show a very good agreement with charge exchange recombination spectroscopy ͑XRS͒ and electron cyclotron emission ͑ECE͒ diagnostics available at TEXTOR-94. The measured values of the ratio Ar 15ϩ /Ar 16ϩ are higher than that predicted from coronal equilibrium. The ratio depends strongly upon the electron density both for ohmic and neutral beam injection cases. This suggests that the charge state distribution is also dependent on diffusion and charge exchange processes in the plasmas.

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Section: Introductionmentioning

confidence: 99%

High-resolution x-ray crystal spectrometer/polarimeter at torus experiment for technology oriented research-94

Weinheimer

Ahmad

Herzog

et al. 2001

Review of Scientific Instruments

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“…These include measurement of T_ from the ratio IJ/I", the departure of Fe charge states from ionization equilibrium, dielectronic recombination rates, and impurity transport rates. Theoretical work by Gabriel and coworkers was used as a basis for some of these measurements [37] . The TFR Group has recently reported similar studies in the OSX region for oxygen ions f124J.…”

Section: B the X-ray Crystal Spectrometermentioning

confidence: 99%

“…These instruments permit measurement of a variety of important plasma parameters. These include electron [8,37,45] and ion [22] temperatures, density [31], plasma equilibrium and stability [23,24], plasma position, and plasma rotation [6] . Other parameters inferred from X rays relate to impurities and include radiative energy loss [10,[32][33][34][35], concentration [6,8,10] and motion [36], charge-state distribution [21,371, wavelengths of emission lines [38][39][40][41][42], and atomic physics parameters such as cross sections for excitation, ionization, and recombination [43,44,46,47].…”

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Low energy x-ray emission from magnetic fusion plasmas

Hill

Bitter

Eames

et al. 1981

AIP Conference Proceedings

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“…This has been specially true for dielectronic satellite transitions associated with the emission of the closed-shell helium-like ions of elements with atomic number Z 18, which have been observed in laboratory measurements, the Sun, and in astrophysical sources (Gabriel 1972;Bitter et al 1979Bitter et al , 2003Gu et al 2012); in addition, lower-Z ions also display dielectronic satellite lines (Faucher et al 1983;Wargelin et al 2001). The reason for their importance is that they can be used as an accurate diagnostic of electron temperature (Dubau & Volonté 1980).…”

Section: Introductionmentioning

confidence: 99%

L-SHELL DIELECTRONIC SATELLITE TRANSITIONS OF Fe XVII

Beiersdörfer

Bode

Ishikawa

et al. 2014

ApJ

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We have used the relativistic multi-reference Møller-Plesset perturbation theory to calculate the positions of the dielectronic satellite transitions involving doubly excited 3 3 configurations that are associated with the X-ray spectrum of Fe xvii. A comparison of these positions with the wavelengths employed in astrophysical modeling codes shows discrepancies of up to 36 mÅ. Inspection of the spectrum of Capella recorded with the high energy transmission grating on the Chandra X-Ray Observatory reveals several features enhanced by Fe xvi lines formed by dielectronic recombination, one of which may be of future diagnostic use as it is fairly well isolated and in large part formed by dielectronic recombination.

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Dielectronic Satellite Spectrum of Heliumlike Iron (Fe XXV)

Abstract: This structure disappears with increasing electron temperature and is ascribed to weak n*2 satellites, such as a_, and to n = 3 satellites, respectively. Table I Experimental and theoretical wavelengths are listed in ACKNOWLEDGMENTS

Cited by 166 publications

References 10 publications

High-resolution x-ray crystal spectrometer/polarimeter at torus experiment for technology oriented research-94

High-resolution x-ray crystal spectrometer/polarimeter at torus experiment for technology oriented research-94

Low energy x-ray emission from magnetic fusion plasmas

L-SHELL DIELECTRONIC SATELLITE TRANSITIONS OF Fe XVII

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