Abstract
Recent atomic data have been used to analyze a solar flare spectrum obtained with the Goddard Space Flight Center's grating spectrometer on the OSO-5 satellite. There exist in the wavelength region 90–200 Å strong lines from each of the ions Fe xviii-Fe xxiv. The Fe xxi lines can be used as an electron density diagnostic for the 107 K plasma. From our analysis of a particular flare, we find a steep positive slope in the emission measure between 106.5 and 107.2 K and an electron density of ∼4 × 1011 cm−3 at 107 K. We emphasise the need for high spectral and spatial resolution observations of solar flares in this wavelength region, which has to date been largely neglected.
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Mason, H.E., Bhatia, A.K., Kastner, S.O. et al. Diagnostic application of highly ionized iron lines in the XUV spectrum of a solar flare. Sol Phys 92, 199–216 (1984). https://doi.org/10.1007/BF00157246
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DOI: https://doi.org/10.1007/BF00157246