Polar plumes are thin long ray-like structures that project beyond the limb of the Sun polar regions, maintaining their identity over distances of several solar radii. Plumes have been first observed in white-light (WL) images of the Sun, but, with the advent of the space era, they have been identified also in X-ray and UV wavelengths (XUV) and, possibly, even in in situ data. This review traces the history of plumes, from the time they have been first imaged, to the complex means by which nowadays we attempt to reconstruct their 3-D structure. Spectroscopic techniques allowed us also to infer the physical parameters of plumes and estimate their electron and kinetic temperatures and their densities. However, perhaps the most interesting problem we need to solve is the role they cover in the solar wind origin and acceleration: Does the solar wind emanate from plumes or from the ambient coronal hole wherein they are embedded? Do plumes have a role in solar wind acceleration and mass loading? Answers to these questions are still somewhat ambiguous and theoretical modeling does not provide definite answers either. Recent data, with an unprecedented high spatial and temporal resolution, provide new information on the fine structure of plumes, their temporal evolution and relationship with other transient phenomena that may shed further light on these elusive features.

中文翻译：

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太阳冠羽

极羽是细长的类似射线的结构，突出到太阳极地区域的四肢之外，并在多个太阳半径的距离内保持其身份。最初在太阳的白光（WL）图像中观察到了羽状物，但是随着太空时代的来临，也已经在X射线和UV波长（XUV）中，甚至在原位也鉴定出了羽状物。数据。这篇评论追溯了烟羽的历史，从烟羽首次被成像到如今我们尝试重建其3D结构的复杂方法。光谱技术还使我们能够推断出羽流的物理参数，并估计其电子和动力学温度及其密度。但是，也许我们需要解决的最有趣的问题是它们在太阳风的起源和加速中所扮演的角色：太阳风是从羽状流还是嵌入它们的周围日冕孔中散发出来的？羽流对太阳风的加速和质量负荷有影响吗？这些问题的答案仍然有些模棱两可，理论模型也无法提供确切的答案。具有空前的高时空分辨率的最新数据，