Using MHD seismology by observed kink waves, the magnetic field profile of a coronal streamer has been investigated. STEREO-B/EUVI temporal image data on 7 March 2012 shows an evolution of two consecutive EUV waves that interact with the footpoint of a coronal streamer evident in the co-spatial and co-temporal STEREO-B/COR-I observations. The evolution of EUV waves is clearly evident in STEREO-B/EUVI, and its energy exchange with coronal streamer generates kink oscillations. We estimate the phase velocities of the kink wave perturbations by tracking it at different heights of the coronal streamer. We also estimate the electron densities inside and outside the streamer using SSI of polarized brightness images in STEREO-B/COR-1 observations. Taking into account the MHD theory of kink waves in a cylindrical waveguide, their observed properties at various heights, and density contrast of the streamer, we estimate the radial profile of magnetic field within this magnetic structure. Both the kink waves diagnose the exponentially decaying radial profiles of the magnetic field in coronal steamer upto 3 solar radii. Within the limit of uncertainties in the measurements, it is indicated that coronal magnetic field of the streamer varies slowly in time at various heights, although its nature always remains exponentially decaying. It is seen that during the evolution of second kink motion in the streamer, it increases in brightness, and also in areal extent slightly, which may be associated with the decreased photospheric magnetic flux at its footpoint. As a result, the magnetic field profile produced by the second kink wave is reduced within the streamer compared to the one diagnosed by the first one. The precisely estimated magnetic field profiles with the uncertainty less than 10% match well with the empirical profile and various observational estimations of the outer coronal magnetic field.
An extreme ultraviolet wave generating upward secondary waves in a streamer-like solar structure
极紫外（EUV）波是低日冕中水平传播的扰动，当它遇到日冕结构时，往往会触发水平二次波。我们提出了第一个例子，向上SW在一个流光状的结构后，通过的EUV波。事件发生在2017年6月1日。极紫外波发生在一次典型的太阳爆发中，包括暗条爆发、CME、C6.6耀斑。EUV波与准周期快速传播（QFP）波列和代表日冕激波存在的II型射电爆发有关。极紫外波有一个快速的初始速度$\sim$ 1000 km s $^{-1}$，相当于高速度的冲击波和QFP波列。有趣的是，向上SW上升缓慢（$\sim$ 80 km s $^{-1}$）的流光状结构后，扫描的EUV波。向上的SW似乎起源于由EUV波引起的临边增亮。结果表明，极紫外波是一种快模磁流体动力学激波，可能是由耀斑脉冲触发的。我们认为部分EUV波可能被捕获在类似流光结构的闭合磁场中，向上的SW可能是由于捕获波以慢模形式释放而产生的。据认为，日冕激波的强烈压缩和流光状结构的配置的相互作用是形成向上SW的关键。
Three-dimensional reconstruction of CME-driven shock-streamer interaction from radio and EUV observations: a different take on the diagnostics of coronal magnetic fields
Fine Structures of an EUV Wave Event from Multi-Viewpoint Observations
在这项研究中，我们调查了2010年2月11日的极紫外（EUV）波事件，从地球的观点来看，它是一个肢体事件，从STEREO-B的观点来看，它是一个磁盘事件。我们使用的数据获得的大气成像组件（AIA）搭载太阳动力学天文台（SDO）在各种EUV通道。极紫外波事件是由部分日珥爆发引发的。与以前的一些EUV波事件类似，这个EUV波事件包含一个速度为$\sim$ 445 $\pm$ 6 km s $^{-1}$的较快波，我们称之为日冕莫顿波，和一个速度为$\sim$ 298 $\pm$ 5 km s $^{-1}$的较慢波，我们称之为“EIT波”。日冕Moreton波被确定为快模波，而“EIT波”被确定为由于连续的场线拉伸引起的明显传播。我们还观察到了与快模EUV波相关的静止波前。这种静止的前面被解释为模式转换从日冕摩顿波的慢模式波附近的流光。
No Trace Left Behind: Stereo Observation of a Coronal Mass Ejection without Low Coronal Signatures
SOHO任务期间对极紫外线和可见日冕的高质量天气观测的可用性提高了我们对CME低日冕表现的理解。EUV成像仪/白光日冕仪的连接已经被证明是如此强大，通常假设当日冕仪观察到CME时，如果没有EUV特征，那么事件必须起源于可见的边缘。这一假设对空间天气预报有很大的影响，但尚未得到检验。本文提出了第一次详细分析的正面，大规模的日冕物质抛射，没有明显的对应物在低日冕。SECCHI仪器观察到该事件。COR2A日冕物质抛射观测到慢磁绳型日冕物质抛射，而COR2B日冕物质抛射观测到极微弱的部分晕。该事件发展非常缓慢，是典型的拖缆井喷CME类。EUVI A 171图像显示，在东翼上方有一个凹形特征，在爆发前两天左右相对稳定，当时它上升到日冕区域并发展成为CME的核心。在EUVI-B图像中没有观察到CME的典型低日冕特征，我们将其归因于通量绳升空的异常大的高度。这种解释得到了CME质量测量和预期EUV调光强度估计的支持。多亏了这两个视角的可用性，我们才能够确定可能的来源区域。这一事件起源于宁静的太阳上的一条中性线。在磁盘的可见（从STEREO B）面上的任何地方都不存在活动区域。在太阳盘面上没有留下任何痕迹，这一观测结果明确地表明，CME爆发不需要有明确的盘面特征。
COCONUT, a novel fast-converging MHD model for solar corona simulations: II. Assessing the impact of the input magnetic map on space-weather forecasting at minimum of activity
Spectroscopic Observations of the Solar Corona during the 2017 August 21 Total Solar Eclipse: Comparison of Spectral Line Widths and Doppler Shifts Between Open and Closed Magnetic Structures
