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arXiv 1208.2071astro-ph.SR
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利用高分辨率数据研究日冕抛射特性

Study of CME properties using high resolution data

ISTP SB RAS(俄罗斯科学院西伯利亚分院天体物理研究所)

V. G. Fainshtein, Ya. I. Egorov

AI总结:

利用高分辨率数据研究日冕抛射的两种类型及其速度变化特征

摘要:

利用PROBA2和SDO卫星的高分辨率数据以及LASCO/SOHO的日冕仪,使我们能够研究2010年6月至2011年6月期间记录的六个边缘日冕抛射(CME)的早期阶段。对于五个事件,CME的启动由日冕(耀斑)喷发或具有另一种性质的环状结构标记。随后,在CME启动区域出现了一系列亮度更高、以不同速度相继出现的环状结构。CME的前缘结构由这些环状结构形成。我们获得了所有考虑事件的前缘速度和加速度的时间变化数据。我们得出结论,可能存在两种CME类型,这取决于其速度时间曲线。第一种CME类型包括在达到最大速度后突然下降超过100 km/s的喷射,随后进入缓慢减速或变化阶段。第二种CME类型由在达到最大速度后速度变化不显著的喷射组成。CME的角大小在传播初期增加到三倍;在首次测量该参数后的3.5-11分钟内,其增加了一倍。当考虑三个CME时,我们发现它们的展宽在传播初期的某一时期超过了其在经向方向上的延伸。

英文摘要:

The joint use of high-resolution data from PROBA2 and SDO satellites and LASCO/SOHO coronographs enabled us to examine early stages of initiation and propagation of six limb CMEs registered in June 2010 - June 2011. For five events under consideration, the CME initiation is marked by filament (prominence) eruption or by a loop-like structure having another nature. Subsequently, several loop-like structures having higher brightness and following each other at different velocities appear in the region of the CME initiation. The CME frontal structure is formed by these loop-like structures. The time-dependent velocities and acceleration of the ejection front have been obtained for all CMEs under consideration. We have drawn a conclusion about the possible existence of two CME types dependent on the time profile of their velocity. The first CME type comprises the ejections whose velocity decreases abruptly by more than 100 km/s after having reached the maximum; it thereupon passes to slow deceleration/variation. The second CME type is formed by the ejections whose velocity varies insignificantly after reaching the maximum. The CME angular size is shown to increase up to threefold at the initial stage of propagation; it increases twofold 3.5-11 minutes after the first measurement of this parameter. When considering 3 CMEs, we see that their broadening exceeds their extension in the longitudinal direction during a certain period of time at the initial propagation stage.

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