ABSOLUTE ABUNDANCES OF FLARING CORONAL PLASMA-DERIVED FROM SMM SPECTRAL OBSERVATIONS

X-ray spectra simultaneously observed by the Flat Crystal Spectrometer and Bent Crystal Spectrometer on Solar Maximum Mission have been analyzed for two solar flares. Elemental abundances for O, Ne, Mg, Si, S, Ca, and Fe with respect to hydrogen have been derived with the aid of a differential emission measure analysis. Absolute abundances of elements with a high first ionization potential (FIP) are depleted in the corona relative to their photospheric values. An indication for a gradual change in the coronal-to-photospheric abundance ratio as a function of FIP is found, rather than the step-function distribution associated with solar energetic particles. The coronal abundance of low-FIP calcium is enhanced by a factor of 1.5-2.0, while the high-FIP oxygen is depleted by a factor of 0.25, with respect to photospheric abundances. Anomalous values of neon and argon abundances are discussed.