Large-scale activity in solar powerful eruptive events of November 2004 by SOHO/EIT data,
by I.M. Chertok

Based on the EUV SOHO/EIT data, we analyze large-scale solar disturbances associated with a series of powerful flares and coronal mass ejections (CMEs) that occurred on 3–10 November 2004, at the late descending phase of the 23th cycle and caused severe geomagnetic storms. Using derotated fixed-base difference images in the 195 Å coronal channel with 12-min cadence as well as in the 171, 195, 284, 304 Å diverse-temperaturechannels with 6-hour cadence, it is shown that these disturbances had a global character and were homologous, i.e. revealed analogous features and affected the same structures. Practically in all 9 events of this series, two recurring system of dimmings (regions of a decreased brightening with life-time of the order of 10–15 h) were observed: (a) trans-equatorial dimmings connecting the north near-equatorial eruptive center with a south active region; (b) north dimmings covering a large sector between two coronal holes. In the same north sector, coronal waves (brightenings propagating from the eruptive center with speed of hundreds of km/s) were observed before expanding dimmings. In each event, the brightest central part of a CME corresponded to the north dimming system. On basis of the received results, some points are discussed: features of dimmings and coronal waves, relations between them, the homology nature of these disturbances in recurring events, oscillations of coronal streamers under the influence of a CME, and so on.