文摘

Radiobursts exhibiting fine structure observed over two years during the rising phase of Cycle 24 by the Chinese Solar Broadband Radio Spectrometer (SBRS/Huairou) in the range 1?–-.6?GHz and the spectrograph IZMIRAN in the meter range (25?–-70?MHz) are analyzed. In five events the zebra structure, various fiber bursts, and fast pulsations were observed. These observations have great importance for testing different theoretical models of fine structure formation, as, for example, only for explaining the zebra structure more than ten mechanisms have been proposed. The events on 15 and 24 February 2011 are of the greatest interest. In the course of the flare on 15 February (which occurred close to the center of disk) the zebra structure was observed during three sequential flare brightenings. The polarization changed sign in the third. This behavior of polarization combined with images of the corresponding flare brightenings, obtained in extreme ultraviolet radiation by the Solar Dynamics Observatory (SDO/AIA, 171 ?), provides important clues. The polarization of radio emission in all three cases is related to the ordinary wave mode of radio emission. The zebra structure was present at frequencies 190?–-20?MHz in the Culgoora spectrum. The event on 24 February 2011 is remarkable, as the zebra structure at frequencies of 2.6?–-.8?GHz was not polarized and it appeared during the magnetic reconnection observed by SDO/AIA 171?? in this limb flare. In the event on 9 August 2011, for the first time, a superfine millisecond structure was registered simultaneously in the fast pulsations and the stripes of the zebra structure. In the event on 1 August 2010 after the zebra structure two families of fibers bursts with opposite frequency drifts were observed. On 19 April 2012 the fibers against the background of type III bursts were observed by IZMIRAN and Nan?ay spectrographs. In the band of 42?–-2?MHz a group of nine slowly drifting narrow-band (