ИСТИНА

The C1.5 solar flare occurred on June 7, 2012 in AR11494. The AR was betaconfiguration with single well-developed spot. This weak flare showed an extraordinary long flat emission in light curve of the X-ray flux in the 3-12 keV energy band. The duration of this period was about 7 minutes while the duration of the flare was less than 20 minutes. As the shape was observed both by RHESSI and FERMI, it could not be considered as an instrumental effect. Analysis was carried out based on the optical spectra and slit-jaw images by the solar spectrograph in Ondrejov, observation in the hard X-ray by RHESSI, EUV data obtained by SDO and all available microwave data. We found that the Ş flat emissionŤ period was also observed by microwaves (5-17 GHz). During this period the motion of the flare source from the spot to south direction was revealed. The maximum of the chromospheric emission also shifted in the same direction. The quasi-periodic pulsation with period about 5 minutes were detected in evolution of the electron temperature.