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On the two classes of filament-prominence disappearance and their relation to coronal mass ejections
We analyze the phenomenon of sudden disappearance (DB) of quiescent filaments and prominences, with examples of the two classes (dynamic and thermal DB) observed on the solar disk and at the limb. The differences between their dynamics are discussed, and it is shown that only dynamic DBs are associated with coronal mass ejections (CME), whereas thermal DBs are only local disturbances of the lower corona. We finish with a discussion of DBs detected on the disk and limb, to explain the statistical differences between the disappearance of filaments and the production of CME. 相似文献
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In this paper we study the longitudinal distribution of solar magnetic regions, using the synoptic magnetic maps from Kitt Peak National Observatory, the active region data from Solar Geophysical Data and the Hobservations from Prairie View Solar Observatory. The clusters of activity were identified by comparing the positions of sunspot groups between successive Carrington rotations. We have found that a large percentage of active regions was involved in the clustering process (40–50%, if we only take into account clusters with a minimum lifetime of 4 rotations). The nests followed the differential rotation of the solar surface, within an intrinsic spread. A remarkable feature of sunspot nests detected in our study is their high degree of complexity, with a large number of nests being organized in diverging, converging, or parallel structures. Of the flares which occurred during the time interval of interest, the great majority originated from the sunspot nests; the distribution of the flares between these nests was not uniform, revealing active and quiet nests. A high flaring rate was recorded at the intersection points of diverging or converging nests, suggesting that these points represent violent interactions of magnetic fluxes. The complexes were in continuous interaction, which impacts their properties and future evolution. The behavior of the nests indicate that they are maintained by repeated injection of magnetic flux rather than by the evolution of the surface magnetic fields. 相似文献
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Previous studies have shown that the measured velocity field in solar prominences exhibits a slightly different behaviour depending on the observational conditions, on the investigation method, and possibly on the type of prominence. Observations of prominences seen at the limb reveal strong downward motions, whereas upflows are detected as Doppler shifts in filaments on the disk. In order to shed new light on this point, we have investigated the mass motions in a solar prominence by using a new method for calculating the geometric distortion between subsequent images. Flows perpendicular to the line of sight have been determined in several layers of the prominence-corona atmosphere, using extreme ultraviolet (EUV) lines formed at different temperature levels (T=104–106 K). We show that the motions mainly have a vertical direction, oriented both upwards and downwards. The velocity pattern can change rapidly during time intervals exceeding 10–15 min. We also find that the measured velocity field shows a similar pattern in all the studied lines. 相似文献
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