  Using methods of differential evolution (DE,) we determined the coronal
elemental abundances and the differential emission measure (DEM) distributions
for the plasma flaring on 2003 January 21. The analyses have been based on
RESIK X-ray spectra. DE belongs to the family of evolutionary algorithms. DE is
conceptually simple and easy to be implemented, so it has been applied to solve
many problems in science and engineering. In this study we apply this method in
a new context: simultaneous determination of plasma composition and DEM . In
order to increase the confidence in the results obtained using DE, we tested
the use of its algorithms by comparing the DE synthesized spectra with
respective spectra observed by RESIK. Extensive discussion of the DE method
used and the obtained physical characteristics of flaring plasma is presented.

Solar and Stellar Astrophysics