Elongation and Separation of Flare Ribbons by Using SDO/AIA
| Autor: | Yun-Chen Yang, 楊昀蓁 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 The flare ribbon structure seen in ultraviolet images can be either caused by the flare-accelerated particles impacting on the lower solar atmosphere or related to the thermal conduction. Besides the separation between two ribbons expected by the CSHKP model, the elongation of flare ribbons along the magnetic polarity inversion line is also observed. In order to figure out the possible causes of ribbon elongation, we used the SDO/AIA 1600 Å data in this study to analyze 46 selected flare events from 2011 February to 2014 December. The maximum gradient of brightening in a stack-plot is taken as the outermost boundary of a flare ribbon for speed estimations. We found that in the impulsive phase, the averaged elongation speed (~56 km/s) is larger than the averaged separation speed (~26 km/s). In addition, the elongation motion can be classified into three groups, namely, the same direction between two ribbons (18 events in total), the opposite directions (23 events in total) between two ribbons, and the motion only seen in one side of flare ribbons (5 events in total). There is no apparent correlation between the elongation speed and the peak of F ̇_SXR and F_SXR, and the F_SXR fluence. But those flares with the larger F_SXR peak or the larger F_SXR fluence are likely to be associated with the opposite elongation, which can be studied more detailed in a future. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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