Solar filament oscillations have been known for decades. Now thanks to the new capabilities of the new telescopes, these periodic motions are routinely observed. Oscillations in filaments show key aspects of their structure. A systematic study of filament oscillations over the solar cycle can shed light on the evolution of the prominences. This work is a proof of concept that aims to automatically detect and parameterise such oscillations using H$α$ data from the GONG network of telescopes. The proposed technique studies the periodic fluctuations of every pixel of the H$α$ data cubes. Using the FFT we compute the power spectral density (PSD). We define a criterion to consider whether it is a real oscillation or whether it is a spurious fluctuation. This consists in considering that the peak in the PSD must be greater than several times the background noise with a confidence level of 95\%. The background noise is well fitted to a combination of red and white noise. We applied the method to several observations already reported in the literature to determine its reliability. We also applied the method to a test case, which is a data set in which the oscillations of the filaments were not known a priori. The method shows that there are areas in the filaments with PSD above the threshold value. The periodicities obtained are in general agreement with the values obtained by other methods. In the test case, the method detects oscillations in several filaments. We conclude that the proposed spectral technique is a powerful tool to automatically detect oscillations in prominences using H$α$ data.
Elongation of a Solar Filament and its Three-Dimensional Numerical Reconstruction for Magnetic Structures
Kumaun University(库马恩大学);Nanjing University(南京大学);KU Leuven(荷语鲁汶大学);Observatoire de Paris, Université PSL(巴黎天文台,巴黎文理研究大学);Sorbonne Université(索邦大学);Université Paris Cité(巴黎西岱大学);University of Glasgow(格拉斯哥大学)
Two Step Filament Eruption During 14-15 March 2015
我们在这里介绍了2015年3月14日至15日期间有趣的两步灯丝喷发。这条暗条位于NOAA AR 12297,与一个晕日冕物质抛射(CME)有关。我们使用来自太阳动力学天文台(SDO)上的大气成像组件(AIA)和日光层磁成像仪(HMI)仪器以及太阳和日光层天文台(SOHO)大角度和光谱日冕仪(LASCO)的观测结果。我们还使用来自全球振荡网络组(GONG)望远镜和Kanzelhoehe太阳天文台的H-α数据。灯丝显示了2015年3月14日的第一次喷发,它在太阳盘面上的投影高度约125 Mm处停止上升。它保持在这个高度约12小时。最后,它在2015年3月15日爆发,并产生了一个光环CME。我们还发现,在这两天的活动区喷流活动,这可能有助于暗条的不稳定和爆发。衰变指数的计算,以了解这两个步骤的喷发。爆发可能是由于连续的不稳定-稳定-不稳定区的存在,因为暗条正在上升。
Hemispheric Preference and Cyclic Variation of Solar Filament Chirality from 2000 to 2016
众所周知,太阳暗条是太阳大气中的特征,其手性表现出半球偏好性。在北半球右旋手征占主导地位,而在南半球左旋手征占主导地位的半球偏好。然而,确定这种半球偏好程度的强度和周期变化是具有挑战性和繁琐的,因此需要自动化。在本文中,我们遵循Pietro Bernasconi博士的算法(Bernasconi et al.2005)来检测具有两个并行应用通道的细丝手性。通过“高级自动灯丝检测和表征代码”(AAFDCC)(Bernasconi等人,2005)将该算法应用于H-α图像,或者向人类解释该算法,并且人类确定太阳灯丝的手性。我们对2000年至2016年8月期间的数据进行了这项工作,我们发现83%的视觉确定的细丝遵循半球手性偏好,而58%的自动确定的细丝遵循它。我们的视觉编译结果与Pevtsov等人的结果有90%以上的一致性。(2003),然而,目视测定的细丝手性与自动测定明显不一致。我们发现,在太阳活动周期23和24之间,半球的偏好保持不变,但在2008-2010年的太阳活动极小期,主要是由于没有暗条,这种偏好很难确定。
SPACE-SUIT: An Artificial Intelligence Based Chromospheric Feature Extractor and Classifier for SUIT
Thapar Institute of Engineering(泰帕工程学院);Inter-University Centre for Astronomy(跨大学天文中心);SETI Institute, Mountain View, CA, USA(SETI研究所);Astrophysics Laboratory, Palo Alto, CA, USA(天文学实验室);Manipal Centre for Natural Sciences, Manipal Academy of Higher Education(曼普及自然科学中心);Department of Physics, Tezpur University(物理系);Ramakrishna Mission Residential College(拉玛克里希纳使命住宅学院);Hansraj College, University of Delhi(汉萨尔学院)
本文提出面向 SUIT 的 SPACE-SUIT 算法,利用 YOLO 检测和分类 Mg II k 图像中的谱斑、黑子、暗条和临边外结构,并通过统计度量与 Tamura 特征进行自验证,在模拟数据上取得约 0.874 的 MAP。