The x-ray package for spectroscopic measurements of solar plasma composition Original Research Article

We present the instrument package dedicated to spectroscopic studies of coronal flaring plasma composition. The package consists of two Bragg spectrometers, RESIK and DIOGENESS. These instruments will be launched aboard the Coronas-F solar observatory mid-2001. The relative abundance of certain elements (Ca) in flaring plasma heated to several million Kelvins (MK) is known to vary up to the factor of around 4 from flare to flare. Two spectrometers have capabilities of determining the absolute abundances of several important elements including low and high first ionization potential (FIP) ones. It will be possible to investigate fast temporal (∼ 1 min) changes of the plasma composition in flares and hotter active regions. This will lead to a better understanding of the processes causing elemental differentiation within the coronal plasma. The RESIK spectrometer was developed by a Consortium including NRL (USA), MSSL (UK), RAL (UK), IZMIRAN (Russia) and the Space Research Centre (SRC) of the Polish Academy of Sciences. DIOGENESS was developed in Poland and in the Astronomical Institute of the Czech Republic.