A New Analysis Procedure for Detecting Periodicities within Complex Solar Coronal Arcades
A New Analysis Procedure for Detecting Periodicities within Complex Solar Coronal Arcades
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DOI：
10.3847/1538-4357/ab264c
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发表时间：
2019-02
期刊：
影响因子：
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通讯作者：
Farhad Allian;R. Jain;B. Hindman
中科院分区：
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作者：
Farhad Allian;R. Jain;B. Hindman
我们研究的强度变化，作为测量的大气成像组件上的太阳动力学天文台，在太阳日冕拱廊使用新开发的分析程序，采用时空自相关性。我们通过研究一个复杂拱廊内由附近燃烧活动激发的大振幅振荡来测试我们的新方法，并检测到12.31分钟的主导周期。我们用传统的时距拟合方法和新的自相关方法来计算这个周期。这两种分析得出了一致的结果。然后在时间序列上实现自相关过程，传统方法由于重叠环路的复杂性和环路与背景之间的对比度差而失败。利用这一新的程序，我们发现在同一拱廊内存在小振幅振荡，分别在大振幅振荡之前和之后的9.13和9.81分钟周期。因此，我们将这些识别为“无衰减”振荡，这些振荡以前只在非燃烧环路系统中观察到过。
We study intensity variations, as measured by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory, in a solar coronal arcade using a newly developed analysis procedure that employs spatio-temporal autocorrelations. We test our new procedure by studying large-amplitude oscillations excited by nearby flaring activity within a complex arcade and detect a dominant periodicity of 12.31 minutes. We compute this period in two ways: from the traditional time–distance fitting method and using our new autocorrelation procedure. The two analyses yield consistent results. The autocorrelation procedure is then implemented on time series for which the traditional method would fail due to the complexity of overlapping loops and a poor contrast between the loops and the background. Using this new procedure, we discover the presence of small-amplitude oscillations within the same arcade with 9.13 and 9.81 minute periods prior and subsequent to the large-amplitude oscillations, respectively. Consequently, we identify these as “decayless” oscillations that have only been previously observed in nonflaring loop systems.