Atomic data from the IRON Project

Storey, P. J.; Zanna, G. Del; Mason, H. E.; Zeippen, C. J.

doi:10.1051/0004-6361:20041771

Cited by 56 publications

(74 citation statements)

References 27 publications

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“…the 1−42 is a well-known and very good electron density diagnostic. The curves form the Malinovsky & Heroux (1973) observation indicate an electron density log N e = 8.5 cm −3 , in excellent agreement with the values derived from other ions such as Fe xii (Storey et al 2005;. Good agreement is also found in Hinode/EIS spectra, although the strongest line, the 1−42 180.40 Å, consistently has an observed intensity that is too low by a 20% or so (cf.…”

Section: Level 25supporting

confidence: 85%

Benchmarking atomic data for astrophysics: Fe xi

Zanna¹

2010

A&A

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High-resolution spectroscopic observations of the solar corona and laboratory measurements are used to review all the line identifications for Fe xi, from the EUV to the visible. The results of the atomic structure and scattering calculations are presented elsewhere, while detailed comparisons between observed and predicted wavelengths and intensities are discussed here. All the brightest EUV lines in the solar corona are now finally firmly identified. Several new identifications are proposed, in particular, coronal forbidden lines. The previously-known density-diagnostics are confirmed. New and important temperature diagnostics are presented, and the presence of blends highlighted.

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Section: Level 25supporting

confidence: 85%

Benchmarking atomic data for astrophysics: Fe xi

Zanna¹

2010

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“…We note that the atomic data for Si X and Fe XIII have recently been updated, as described in Liang et al (2009) and Storey & Zeippen (2010). The most recent atomic data for Fe XII is discussed in Storey et al (2005). Further checks on line blending are in progress.…”

Section: Densitiesmentioning

confidence: 97%

Hinode extreme-ultraviolet imaging spectrometer observations of a limb active region

O’Dwyer¹,

Zanna²,

Mason³

et al. 2010

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Aims. We investigate the electron density and temperature structure of a limb active region. Methods. We have carried out a study of an active region close to the solar limb using observations from the Extreme-ultraviolet Imaging Spectrometer (EIS) and the X-ray telescope (XRT) on board Hinode. The electron density and temperature distributions of the coronal emission have been determined using emission line intensity ratios. Differential emission measure (DEM) analysis and the emission measure (EM) loci technique were used to examine the thermal structure of the emitting plasma as a function of distance from the limb. Results. The highest temperature and electron density values are found to be located in the core of the active region, with a peak electron number density value of 1.9 × 10 10 cm −3 measured using the Fe XII 186.887 Å to 192.394 Å line intensity ratio. The plasma along the line of sight in the active region was found to be multi-thermal at different distances from the limb. The EIS and XRT DEM analyses appear to be in agreement in the temperature interval from log T = 6.5−6.7. Conclusions. Our results provide new constraints for models of coronal heating in active regions.

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“…Historically, large discrepancies between observed and predicted intensities of EUV transitions from the n = 3 levels were found to be present. These discrepancies were finally resolved by Storey et al (2005) via an R-matrix electron collisional calculation carried-out within the Iron Project. References to earlier calculations for the n = 3 levels are given in Storey et al (2005).…”

Section: Previous Observations and Atomic Data For Fe XIImentioning

confidence: 99%

“…The configuration basis describing the target adopted by Storey et al (2005) included 12 of the main n = 3 configurations. For the scattering calculation the lowest 58 LS terms were included, giving rise to 143 fine-structure levels.…”

Section: Previous Observations and Atomic Data For Fe XIImentioning

confidence: 99%

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Atomic data for astrophysics: Fe xii soft X-ray lines

Zanna¹,

Storey

Badnell³

et al. 2012

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We present new large-scale R-matrix (up to n = 4) and distorted-wave (DW, up to n = 6) scattering calculations for electron collisional excitation of Fe xii. The first aim is to provide accurate atomic data for the soft X-rays, where strong decays from the n = 4 levels are present. As found in previous work on Fe x, resonances attached to n = 4 levels increase the cross-sections for excitations from the ground state to some n = 4 levels, when compared to DW calculations. Cascading from higher levels is also important. We provide a number of models and line intensities, and list a number of strong unidentified lines. The second aim is to assess the effects of the large R-matrix calculation on the n = 3 transitions. Compared to our previous (n = 3) R-matrix calculation, we find overall excellent agreement to within a few percent, however a few key density diagnostic EUV intensities differ by about 60% at coronal densities. The new atomic data result in lower electron densities, resolving previous discrepancies with solar observations.

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Atomic data from the IRON Project

Cited by 56 publications

References 27 publications

Benchmarking atomic data for astrophysics: Fe xi

Benchmarking atomic data for astrophysics: Fe xi

Hinode extreme-ultraviolet imaging spectrometer observations of a limb active region

Atomic data for astrophysics: Fe xii soft X-ray lines

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