Small-scale Turbulent Motion of the Plasma in a Solar Filament as the Precursor of Eruption
Small-scale Turbulent Motion of the Plasma in a Solar Filament as the Precursor of Eruption
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DOI：
10.3847/1538-4357/ac0d51
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发表时间：
2021-06
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影响因子：
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通讯作者：
D. Seki;Ken Otsuji;H. Isobe;G. del Zanna;T. Ishii;Takahito Sakaue;K. Ichimoto;K. Shibata
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作者：
D. Seki;Ken Otsuji;H. Isobe;G. del Zanna;T. Ishii;Takahito Sakaue;K. Ichimoto;K. Shibata
灯丝是一种由日冕磁场支撑的致密冷等离子体，经常变得不稳定并爆发。根据经验，暗条经常表现出一些激活，例如喷发前的湍流运动。在我们以前的研究中，我们分析了Hα细丝的多普勒速度，发现细丝中的视线速度分布的标准差，这表明小尺度运动的振幅增加，在爆发开始之前增加。在这里，我们对这一丝状喷发进行了进一步的分析，它大约在2016年11月5日03：40 UT在NOAA活动区12605附近开始。它包括日冕线观测和周围磁场的外推。我们发现，无论是空间平均微湍流内的灯丝和附近的日冕线发射增加6和10小时前爆发，分别。在这次事件中，我们没有发现任何显着的变化，在全球位场配置喷发前的过去2天，这表明有一个情况下，它是难以预测的喷发仅通过跟踪外推的全球磁场。在空间天气预报方面，我们对暗条湍流运动的研究结果可以作为暗条爆发的有用前兆。
A filament, a dense cool plasma supported by the magnetic fields in the solar corona, often becomes unstable and erupts. It is empirically known that the filament often demonstrates some activations such as a turbulent motion prior to eruption. In our previous study, we analyzed the Doppler velocity of an Hα filament and found that the standard deviation of the line-of-sight velocity distribution in a filament, which indicates the increasing amplitude of the small-scale motions, increased prior to the onset of the eruption. Here, we present a further analysis on this filament eruption, which initiated approximately at 03:40 UT on 2016 November 5 in the vicinity of NOAA Active Region 12605. It includes a coronal line observation and the extrapolation of the surrounding magnetic fields. We found that both the spatially averaged microturbulence inside the filament and the nearby coronal line emission increased 6 and 10 hr prior to eruption, respectively. In this event, we did not find any significant changes in the global potential field configuration preceding the eruption for the past 2 days, which indicates that there is a case in which it is difficult to predict the eruption only by tracking the extrapolated global magnetic fields. In terms of space weather prediction, our result on the turbulent motions in a filament could be used as the useful precursor of a filament eruption.