A statistical study on the brightening propagation of post-flare loops

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Abstract

After examining the data observed by TRACE 171 and 195 Å from May 1998 to December 2006, we choose as our sample 190 (39 X-class and 151 M-class) flare events which display post-flare loops (PFLs). We investigate the brightening propagation of these PFLs of the events in the sample along the magnetic neutral lines. In most of the cases, the length of the flare ribbons (FRs) ranges from 20 to 170 Mm. The propagating duration of the brightening lasts 10–60 min. The velocities of the propagation associated with the flare strength and the length of the FRs, range from 5 to 35 km·s−1. Furthermore, a greater propagating velocity corresponds to a greater deceleration (or acceleration). These PFLs display three types of propagating patterns: (1) the brightening begins at the middle part of a set of PFLs, and propagates bi-directionally towards its both ends; (2) the brightening first appears at one end of a set of PFLs, and then propagates to the other; (3) the initial brightening takes place at two (or more than two) positions on two (or more than two) sets of PFLs, and each brightening propagates bi-directionally along the magnetic neutral line.

Keywords

flares magnetic fields corona UV radiation 
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Copyright information

© Science in China Press and Springer Berlin Heidelberg 2009

Authors and Affiliations

  1. 1.Key Laboratory of Solar ActivityNational Astronomical Observatories, Chinese Academy of SciencesBeijingChina
  2. 2.Jiangsu Sopo Corporation Group Ltd.ZhenjiangChina

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