Decaying and decayless transverse oscillations of a coronal loop
Decaying and decayless transverse oscillations of a coronal loop
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DOI：
10.1051/0004-6361/201220676
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发表时间：
2013-04
影响因子：
6.5
通讯作者：
G. Nisticò;V. Nakariakov;E. Verwichte
中科院分区：
文献类型：
--
作者：
G. Nisticò;V. Nakariakov;E. Verwichte
目标。我们调查扭结振荡的环观测到的活动区域与大气成像组件（AIA）仪器板上的太阳动力学天文台（SDO）航天器之前和之后的耀斑。方法.振荡被描绘和分析的时间-距离图，提取的切割平行或垂直于环轴。随着时间的推移，移动的环被稳步移动的狭缝所跟踪。振荡周期及其随时间的变化由最佳拟合的谐波函数确定。结果我们发现，之前和之后的耀斑发生，循环经历低振幅的无衰减振荡。耀斑和与之相关的日冕物质抛射引发了大幅度的振荡，并随时间呈指数衰减。在两个制度（约240秒）的扭结振荡的周期是相似的。一个经验模型的现象中的阻尼线性振荡器激励的连续低振幅谐波驱动器和脉冲高振幅驱动器被发现是一致的观察。
Aims. We investigate kink oscillations of loops observed in an active region with the Atmospheric Imaging Assembly (AIA) instrument on board the Solar Dynamics Observatory (SDO) spacecraft before and after a flare. Methods. The oscillations were depicted and analysed with time-distance maps, extracted from the cuts taken parallel or perpendicular to the loop axis. Moving loops were followed in time with steadily moving slits. The period of oscillations and its time variation were determined by best-fitting harmonic functions. Results. We show that before and well after the occurrence of the flare, the loops experience low-amplitude decayless oscillations. The flare and the coronal mass ejection associated to it trigger large-amplitude oscillations that decay exponentially in time. The periods of the kink oscillations in both regimes (about 240 s) are similar. An empirical model of the phenomenon in terms of a damped linear oscillator excited by a continuous low-amplitude harmonic driver and by an impulsive high-amplitude driver is found to be consistent with the observations.