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J.M. Laming (1,2), J.J. Drake (3), and K.G. Widing (2)
1) SFA Inc., Landover, MD 20785
2) E.O. Hulburt Center for
Space Research, Naval Research Laboratory, Washington DC 20375
3)
Center for EUV Astrophysics, Berkeley, CA 94720
In this paper we reanalyze the full disk quiet sun spectrum of Malinovksy & Heroux (1973) with modern atomic data. The purposes of this are to check our atomic data and methods in other investigations using data from nearby stars obtained with the NASA Extreme Ultraviolet Explorer (EUVE) satellite, and to confirm that the solar FIP effect investigated by previous authors studying discrete solar regions is the same as that found in full disk spectra. We recover the usual solar FIP effect of a coronal abundance enhancement of elements with a low first ionization potential (FIP) of a factor ~ 3-4 for lines formed at temperatures greater than ~ 10E+06 K. For lower temperatures the FIP effect seems to be substantially smaller, in qualitative agreement with other data. Comparing our full disk result with those from discrete solar structures suggests that the FIP effect is a function of altitude, with the lower temperature full disk emission being dominated by the supergranulation network. We also compare the recent Fe ionization balance of Arnaud & Raymond (1992) with that of Arnaud & Rothenflug (1985).
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