The source of unusual coronal upflows with photospheric abundance in a solar active region
The source of unusual coronal upflows with photospheric abundance in a solar active region
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太阳活动区域光球丰度异常的日冕上升流的来源
DOI：
10.1051/0004-6361/202245747
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发表时间：
2023
影响因子：
6.5
通讯作者：
Harra L
中科院分区：
文献类型：
--
作者：
Harra L
日冕中的上下文上升流很重要，因为它们可能会对太阳风做出贡献。人们对活跃地区(AR)的上升流有相当大的兴趣。在活动区边缘看到的日冕上升流具有日冕元素组成，可以促成缓慢的太阳风。上升流的来源很难确定，因为它们可能是多个的，而且以前的观测结果的空间分辨率还不够高。目的本文分析了AR 12960中异常接近太阳黑子本影的日冕上升流。我们分析了它们的性质，并试图确定它们是否有可能进入缓慢的太阳风。方法我们结合高空间和时间分辨率的太阳轨道器EUV图像、Hinode/EUV成像光谱仪数据和太阳动力学观测站上的观测数据，详细分析了上流区的活动。这一组合数据集是在科学阶段的第一个太阳轨道器近日点期间获得的，它为两个像素提供了356公里的空间分辨率。通过多普勒速度、密度和等离子体成分测定以及日冕磁场模拟来了解上升流的来源。结果我们在活动区观察到被称为移动磁性特征(MMF)的微小磁性碎片远离太阳黑子。具体地说，他们从半影的边缘向太阳黑子移动，在那里，一个小的正极通过小范围和非常动态的日冕环连接到本影。在这个位置，小的黑色颗粒很明显，并在连续图像中沿着半影细丝流动。磁场模型显示出靠近本影磁场的小的低位环路。太阳轨道飞行器EUV成像仪的高分辨率数据显示了这些小环路的动态，这些环路的时间尺度只有几分钟。这些小环圈的边缘是具有光球层丰度的日冕上升流的位置。
ContextUpflows in the corona are of importance, as they may contribute to the solar wind. There has been considerable interest in upflows from active regions (ARs). The coronal upflows that are seen at the edges of active regions have coronal elemental composition and can contribute to the slow solar wind. The sources of the upflows have been challenging to determine because they may be multiple, and the spatial resolution of previous observations is not yet high enough.AimsIn this article, we analyse coronal upflows in AR 12960 that are unusually close to the sunspot umbra. We analyse their properties, and we attempt to determine if it is possible that they feed into the slow solar wind.MethodsWe analysed the activity in the upflow region in detail using a combination of Solar Orbiter EUV images at high spatial and temporal resolution, Hinode/EUV Imaging Spectrometer data, and observations from instruments on board the Solar Dynamics Observatory. This combined dataset was acquired during the first Solar Orbiter perihelion of the science phase, which provided a spatial resolution of 356 km for two pixels. Doppler velocity, density, and plasma composition determinations, as well as coronal magnetic field modelling, were carried out to understand the source of the upflows.ResultsWe observed small magnetic fragments, called moving magnetic features (MMFs), moving away from the sunspot in the active region. Specifically, they moved towards the sunspot from the edge of the penumbra where a small positive polarity connects to the umbra via small-scale and very dynamic coronal loops. At this location, small dark grains are evident and flow along penumbral filaments in continuum images. The magnetic field modelling showed small low-lying loops anchored close to the umbral magnetic field. The high-resolution data of the Solar Orbiter EUV Imagers showed the dynamics of these small loops, which last on time scales of only minutes. The edges of these small loops are the location of the coronal upflow that has photospheric abundance.