  We present a multiwavelength analysis of the long duration flare observed on
15 April 2002 (soft X-ray peak time at 03:55 UT, SOL2002-04-15T03:55). This
flare occurred on the disk (S15W01) in NOAA 9906 and was observed by a number
of space instruments including the Extreme-Ultraviolet Imaging Telescope on the
Solar and Heliospheric Observatory (SOHO/EIT), the RESIK spectrometer onboard
the Coronas-F spacecraft, and the Ramaty High Energy Solar Spectroscopic Imager
(RHESSI). We have performed a complex analysis of these measurements and
studied the morphology and physical parameters characterizing the conditions in
flaring plasmas. The 195 A SOHO/EIT images have been used to study evolution of
flaring loops. Analysis of RHESSI data provided the opportunity for a detailed
analysis of hard X-ray emission with 1 keV energy resolution. We have used
Geostationary Operational Environmental Satellite (GOES) observations for
isothermal interpretation of the X-ray measurements. Temperature diagnostics of
the flaring plasma have been carried out by means of a differential emission
measure (DEM) analysis based on RESIK X-ray spectra.
