Fe XIII DENSITY DIAGNOSTICS IN THE EIS OBSERVING WAVELENGTHS

Watanabe, Tetsuya; Hara, Hirohisa; Yamamoto, Norimasa; Kato, Daiji; Sakaue, Hiroyuki; Murakami, Izumi; Katō, Takako; Nakamura, Nobuyuki; Young, Peter R.

doi:10.1088/0004-637x/692/2/1294

Cited by 47 publications

(40 citation statements)

References 25 publications

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“…The effective collision strengths calculated with R-matrix code and the radiative transition probabilities calculated by the GRASP code (GRASP6) [14] are used for the same transitions. The same Y08 model configuration replaced with radiative transition probabilities generated by the new code, GRASP13 [15], is also calculated to see the effects of data replacement [16]. The excitation rate coefficients for proton impact evaluated by Skobelev et al [17] are also included for the transitions between fine structure levels of the ground-state configuration [13,16,18].…”

Section: Collisional Radiative (Cr) Modelmentioning

confidence: 99%

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Evaluation of Spectroscopic Modeling for Iron Ions and Study on Non-Equilibrium Ionization Phenomena for Solar and LHD Plasmas

Watanabe

Hara

Yamamoto

et al. 2013

Plasma and Fusion Research

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Spectroscopic observations of EUV emission lines in the transition region (TR) and the corona provide unique information on physical conditions in the outer atmosphere of the Sun. The EUV Imaging Spectrometer (EIS) on board the Hinode satellite is capable of observing, for the first time in EUV, spectra and monochromatic images of plasmas in the solar TR and corona; these plasmas could possibly be in non-ionization-equilibrium conditions. EIS observes over two-wavelength bands of 170 -210 Å and 250 -290 Å, with typical time-resolutions of 1 -10 seconds. Iron line emissions emerging from these wavelengths reveal that dynamic plasma accelerations and heating take place in the solar atmosphere. On the other hand, the tracer-encapsulated-pellet (TESPEL) experiments provide spectral information of EUV emission lines from iron ions produced in the Large Helical Device (LHD). Relatively cool plasmas with electron temperatures similar to those of the solar corona can be generated by controlling the neutral beam injector (NBI) system. A time-dependent collisional radiative (CR) model for elemental iron is developed as a common tool to diagnose temperatures and densities of those plasmas in the Sun and in LHD; no systematic model yet exists for iron ions in the L-and M-shell ionization stages, which are very important for coronal plasma diagnostics. Adopting the best available theoretical calculations, as well as generating the experimental data, we improve the atomic parameters of highly charged iron ions, and these results are used to extract more accurate diagnostic information out of the EIS spectra.

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Section: Collisional Radiative (Cr) Modelmentioning

confidence: 99%

“…We investigated diagnostic capabilities, especially for density, by a detailed comparison of data from a solar active region, a solar flare, and LHD/EBIT (electron beam ion trap) experiments with values from theoretical calculations [13,16].…”

Section: Case Study -Fe XIII For Density Diagnostics -mentioning

confidence: 99%

Evaluation of Spectroscopic Modeling for Iron Ions and Study on Non-Equilibrium Ionization Phenomena for Solar and LHD Plasmas

Watanabe

Hara

Yamamoto

et al. 2013

Plasma and Fusion Research

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“…The accuracy of the analyzed results from spectroscopic measurements depends on that of the spectroscopic model and the atomic data used in the model. As Hinode EIS measures Fe VIII-XXIV lines for plasma diagnostics as good indices for the solar transition region over a wide electron temperature range, we have constructed collisional-radiative (CR) models for Fe 7+ -Fe 23+ ions to analyze both solar and laboratory plasmas [9][10][11][12][13][14]. We have carefully examined atomic data of Fe ions to be used in the CR models [15,16], and so far, have applied the models to the measurements of laboratory plasmas to validate the CR models and atomic data for Fe XIII [9,14], Fe XIV [14], Fe XV [14], Fe XXI [12], and Fe XXII [13].…”

Section: Introductionmentioning

confidence: 99%

“…Thus, we used a TESPEL to inject iron into LHD plasmas and measured EUV spectra to compare with the model calculations [9,12,13]. The CR model for Fe XIII evaluated using the LHD experiments [9] has been applied to analyze solar spectra measured by Hinode EIS to estimate the electron density distribution in the solar active region [11].…”

Section: Introductionmentioning

confidence: 99%

Validation of Spectroscopic Model for Fe Ions in Non-Equilibrium Ionization Plasma in LHD and Hinode

Murakami

Watanabe

Suzuki

et al. 2014

Plasma and Fusion Research

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We measured extreme ultraviolet spectra of Fe ions for plasmas produced in the Large Helical Device (LHD) at the National Institute for Fusion Science (NIFS). Iron was injected into the plasmas by using a tracerencapsulated pellet. By controlling the neutral beam injection pattern, we could produce plasma with a central electron temperature of approximately 500 eV, which was suitable for producing Fe XVII ions. We measured seven Fe XVII lines. The intensity ratio for λ of 20.468 to 25.493 nm was consistent with the theoretically calculated value of 1.1. This calculated value was determined purely from the branching ratio due to the common upper level of these transitions, although Warren et al. [Astrphys. J. 685, 1277(2008] reported a larger ratio of approxinately 2 from Hinode EIS measurements. The other five ratios for Fe XVII lines in our LHD measurements were also consistent with the theoretical ratios calculated with a collisional-radiative model. A preferred atomic dataset for Fe XVII is suggested to obtain better agreement between the measured and calculated ratios.

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“…the SOHO Coronal Diagnostic Spectrometer (CDS, see Harrison et al 1995) and especially the Hinode EUV Imaging Spectrometer (EIS, see Culhane et al 2007). This latter instrument is more sensitive than CDS and has a higher spectral resolution, so accurate densities can be obtained (see e.g., Watanabe et al 2009;Young et al 2009). …”

Section: Introductionmentioning

confidence: 99%

Benchmarking atomic data for astrophysics: Fe xiii EUV lines

Zanna

2011

A&A

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Recent atomic data for Fe xiii are benchmarked against high-resolution spectroscopic observations of the solar corona. All the identifications of the EUV lines are reviewed by also taking into account laboratory measurements. A few new identifications are proposed, and many wavelengths are revised. All the strongest EUV lines are now identified. Very good agreement between predicted and observed line intensities is generally found using the latest atomic calculations. We clearly indicate which EUV lines are blended, and which are best for electron-density measurements in different regimes.

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Fe XIII DENSITY DIAGNOSTICS IN THE EIS OBSERVING WAVELENGTHS

Cited by 47 publications

References 25 publications

Evaluation of Spectroscopic Modeling for Iron Ions and Study on Non-Equilibrium Ionization Phenomena for Solar and LHD Plasmas

Evaluation of Spectroscopic Modeling for Iron Ions and Study on Non-Equilibrium Ionization Phenomena for Solar and LHD Plasmas

Validation of Spectroscopic Model for Fe Ions in Non-Equilibrium Ionization Plasma in LHD and Hinode

Benchmarking atomic data for astrophysics: Fe xiii EUV lines

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