Atomic data for the astrophysics : Fe XII soft X-ray lines.

Del Zanna, G. and Storey, P. J. and Badnell, N. R. and Mason, H.E. (2012) Atomic data for the astrophysics : Fe XII soft X-ray lines. Astronomy and Astrophysics, 543. A139. ISSN 0004-6361

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    Abstract

    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.

    Creators(s): Del Zanna, G., Storey, P. J., Badnell, N. R. ORCID logoORCID: https://orcid.org/0000-0001-7418-7996 and Mason, H.E.;
    Item type:Article
    ID code:56990
    Notes:Reproduced with permission from Astronomy & Astrophysics, © ESO
    Keywords:atomic data, identification line, spectroscopic techniques, sun, corona, Fe xii, electron collisional excitation, coronal densities, extreme ultraviolet lines, Physics, Astronomy and Astrophysics, Space and Planetary Science
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:19 Jul 2016 15:24
    Last modified:21 Jan 2021 00:01
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/56990
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