The dense prominence material is believed to be supported against gravity through the magnetic tension of dipped coronal magnetic field. For quiescent prominences, which exhibit many gravity-driven flows, hydrodynamic forces are likely to play an important role in the determination of both the large and small scale magnetic field distributions. In this study, we present the first steps toward creating three-dimensional magneto-hydrostatic prominence model where the prominence is formed in the dips of a coronal flux tube. Here 2.5D equilibria are created by adding mass to an initially force-free magnetic field, then performing a secondary magnetohydrodynamic relaxation. Two inverse polarity magnetic field configurations are studied in detail, a simple o-point configuration with a ratio of the horizontal field (B_x) to the axial field (B_y) of 1:2 and a more complex model that also has an x-point with a ratio of 1:11. The models show that support against gravity is either by total pressure or tension, with only tension support resembling observed quiescent prominences. The o-point of the coronal flux tube was pulled down by the prominence material, leading to compression of the magnetic field at the base of the prominence. Therefore tension support comes from the small curvature of the compressed magnetic field at the bottom and the larger curvature of the stretched magnetic field at the top of the prominence. It was found that this method does not guarantee convergence to a prominence-like equilibrium in the case where an x-point exists below the prominence flux tube. The results imply that a plasma beta of ~ 0.1 is necessary to support prominences through magnetic tension.
Triggering process for prominence instability and consequent CMEs is not fully understood. Prominences are maintained by the Lorentz force against the gravity, therefore reduction of the prominence mass due to the coronal rain may cause the change of the force balance and hence destabilisation of the structures. We aim to study the observational evidence of the influence of coronal rain on the stability of prominence and subsequent eruption of CMEs. We used the simultaneous observations from AIA/SDO and SECCHI/STEREO spacecrafts from different angles to follow the dynamics of prominence/filame…
We present magnetohydrodynamic (MHD) simulations of the evolution from quasi-equilibrium to eruption of a prominence-forming twisted coronal flux rope under a coronal streamer. We have compared the cases with and without the formation of prominence condensations, and the case where prominence condensations form but we artificially initiate the draining of the prominence. We find that the prominence weight has a significant effect on the stability of the flux rope, and can significantly increase the loss-of-equilibrium height. The flux rope can be made to erupt earlier by initiating draining of…
The triggering process for coronal mass ejections (CME) in the solar atmosphere is not fully understood. We use observations from different spacecraft at several wavelengths to detect an instability process for a prominence/filament with a subsequent eruption of CME. Time series of spectral lines at 304, 171, 193, and 211 Å have been obtained with the SDO spacecraft, and at 304, 171, 195, and 284 Å with the STEREO spacecraft. A prominence/filament system was observed during November 8-23, 2011, at different angles by SDO, STEREO_A, and STEREO_B. The observations show that a giant tornado began…
Prominence threads are dense and cold structures lying on curved magnetic fields that can be suspended in the solar atmosphere against gravity. The gravitational stability of threads, in the absence of non-ideal effects, is comprehensively investigated in the present work by means of an elementary but effective model. Based on purely hydrodynamic equations in one spatial dimension and applying line-tying conditions at the footpoints of the magnetic field lines, we derive analytical expressions for the different feasible equilibria and the corresponding frequencies of oscillation. We find that …
We present a detailed three-dimensional (3D) view of a prominence eruption, coronal loop expansion, and coronal mass ejections (CMEs) associated with an M4.4 flare that occurred on 2011 March 8 in the active region NOAA 11165. Full-disk H$α$ images of the flare and filament ejection were successfully obtained by the Flare Monitoring Telescope (FMT) following its relocation to Ica University, Peru. Multiwavelength observation around the H$α$ line enabled us to derive the 3D velocity field of the H$α$ prominence eruption. Features in extreme ultraviolet were also obtained by the Atmospheric Imag…
The eruption of a prominence carrying coronal flux rope: forward synthesis of the magnetic field strength measurement by the COronal Solar Magnetism Observatory Large Coronagraph
Observational evidence shows that coronal jets can hit prominences and set them in motion. The impact leads to large-amplitude oscillations (LAOs) of the prominence. In this paper we attempt to understand this process via 2.5D MHD numerical experiments. In our model, the jets are generated in a sheared magnetic arcade above a parasitic bipolar region located in one of the footpoints of the filament channel (FC) supporting the prominence. The shear is imposed with velocities not far above observed photospheric values; it leads to a multiple reconnection process, as in previous jet models. Both …
Simultaneous transverse and longitudinal oscillations in a quiescent prominence triggered by a coronal jet
在本文中，我们报告了2015年6月29日在静止日珥中同时进行的横向和纵向振荡的多波长观测。在活动区12373发生了一次C2.4耀斑，它与一对短带和一个远带有关。在耀斑的脉冲阶段，一个日冕喷流喷出的主耀斑网站，并在西北方向传播的$\sim$ 224 km s $^{-1}$的视速度。飞机的一部分在远处的丝带附近停了下来。剩下的一部分继续前进，最后停在了日珥的东边。一旦喷流遇到日珥，它就会推动日珥周期性地振荡。日珥东部的横向振荡可分为两个阶段。在阶段I中，初始振幅、速度、周期和阻尼时标分别为$\sim$ 4.5 μ m、$\sim$ 20 km s $^{-1}$、$\sim$ 25 min和$\sim$ 7.5 hr。在第二阶段，初始振幅增加到$\sim$ 11.3 Mm，而初始速度减半到$\sim$ 10 km s $^{-1}$。该周期增加了$\sim$ 3.5倍。日珥西部也经历了横向振荡。初始振幅仅为$\sim$ 2 μ m，速度小于10 km/s $^{-1}$。周期（$\sim$ 27分钟）略长于I相的EP。在日珥以东，少数水平线经历了纵向振荡。初始振幅、速度、周期和阻尼时标分别为$\sim$ 52 μ m、$\sim$ 50 km s $^{-1}$、$\sim$ 99分钟和2.5小时。据我们所知，这是第一个由日冕喷流引发的日珥横向和纵向同时振荡的报告。
Longitudinal oscillations in prominences are common phenomena on the Sun. These oscillations can be used to infer the geometry and intensity of the filament magnetic field. Previous theoretical studies of longitudinal oscillations made two simplifying assumptions: uniform gravity and semi-circular dips on the supporting flux tubes. However, the gravity is not uniform and realistic dips are not semi-circular. To understand the effects of including the nonuniform solar gravity on longitudinal oscillations, and explore the validity of the pendulum model with different flux-tube geometries. We fir…
A rising cool column as signature for helical flux emergence and formation of prominence and coronal cavity
2006年12月23日至24日，利用太阳光学望远镜（SOT）对静止日珥进行了连续观测。在观测过程中，从低层大气中发展出一种特殊的缓慢上升的$/sim10^{4}$ K等离子体柱。柱的表观上升速度为2 km/s $^{-1}$，而柱的精细结构表现出更快的运动，高达20 km/s $^{-1}$。柱体最后变成一个微弱的低地突出物。与柱的出现相关联，在X射线和极紫外线中看到的覆盖冕腔在$/sim$ 5 km s $^{-1}$处向上移动。我们讨论了这些情节之间的关系，并建议，他们是由于出现了螺旋磁通绳，经历了与较低的日冕领域的重联，可能携带材料进入冠状腔。在出射通量假设下，柱体中2 km s $^{-1}$的低速和20 km s $^{-1}$的高速分别归因于出射通量的上升运动和出射通量与先存日冕场之间的磁重联驱动的外流。本文对螺旋绳上升柱的神秘现象及其对日冕的影响作了较好的解释。我们讨论的影响，出现这样的螺旋绳发电机过程中的对流区。
High-resolution observations from the $Interface~Region~Imaging~Spectrometer$ ($IRIS$) reveal the existence of a particular type of small solar jets, which arose singly or in clusters from a tornado-like prominence suspended in the corona. In this study, we perform a detailed statistical analysis of 43 selected mini-jets in the tornado event. Our results show that the mini-jets typically have: (1) a projected length of 1.0-6.0 Mm, (2) a width of 0.2-1.0 Mm, (3) a lifetime of 10-50 s, (4) a velocity of 100-350 km s$^{-1}$, and (5) an acceleration of 3-20 km s$^{-2}$. Based on spectral diagnosti…
Hot prominence detected in the core of a Coronal Mass Ejection: III. Plasma filling factor from UVCS Lyman-$α$ and Lyman-$β$ observations
本文研究了嵌入日冕物质抛射核心的爆发日珥，着重于日珥等离子体填充因子的推导。我们探索了两种基于可见光和紫外光谱观测相结合的方法来测量日珥等离子体填充因子。共振散射和碰撞激发的理论关系用于评估H I Lyman-α和Lyman-β线的强度，在两个突出点，同时和共空间LASCO-C2和USCOM数据可用。计算中假设的热力学和几何参数由观测和我们以前的工作（Heinzel 2016）中开发的日珥详细的1D非LTE辐射传输模型的结果提供。填充因子是从两条线的计算强度和测量强度之间的比较得出的。然后，针对非LTE模型检查结果，以验证方法的可靠性。由此产生的填充因子是一致的模型在两个突出点时的总强度的辐射和碰撞分量的分离，需要估计的填充因子，使用两个线强度。参数空间的探索表明，结果是弱等离子体速度的敏感性，但它们更强烈地依赖于假设的动力学温度。可见光和紫外线Lyman-α和Lyman-β数据的组合可以用来近似估计爆发等离子体的几何填充因子，但是所提出的技术仅对所考虑的谱线中光学薄的发射是可靠的，这种条件并不能普遍代表日珥等离子体。
In this work, we study the causal relations between a localised energy release and a remote prominence oscillation, where the prominence has a realistic thread-like structure. We used an open source magnetohydrodynamic (MHD) code known as MPI-AMRVAC to create a multithreaded prominence body. We introduced an additional energy source from which a shock wave originates, thereby inducing prominence oscillation. We studied two cases with different source amplitudes to analyze its effect on the oscillations. Our results show that the frequently used pendulum model does not suffice to fully estimate…
Dynamics of coronal rain and descending plasma blobs in solar prominences: II. partially ionized case
日冕雨团和日珥结是色球层到过渡区温度的密集凝聚，这些温度在更热的日冕中下降。它们的典型速度范围分别为30- 150 km~s $^{-1}$和10- 30 km~s $^{-1}$的数量级，即，它们比自由降落速度小得多。这些冷团块包含电离和中性物质的混合物，它们必须动态耦合才能像观察到的那样落在一起。我们调查这种耦合的流体动力学模拟，其中耦合产生的离子和中性粒子之间的摩擦。这里提出的数值模拟是\citet{oliver2014}的部分电离的情况下的扩展。我们发现，尽管在团簇中心两种粒子的相对漂移速度小于1 m s $^{-1}$，但它足以产生强耦合带电粒子和中性粒子所需的力.对于完全电离的等离子体，电离度对我们以前工作的主要结果没有明显的影响：凝结有一个初始加速阶段，随后是一个大致恒定速度的时期，此外，最大下降速度明显与初始团块与环境密度的比值相关。
First High-resolution Spectroscopic Observations of an Erupting Prominence Within a Coronal Mass Ejection by the Interface Region Imaging Spectrograph (IRIS)
光谱观测日珥喷发与日冕物质抛射（CME），虽然相对罕见，可以提供有价值的等离子体和三维几何诊断。我们报告了2014年5月9日界面区域成像光谱仪（IRIS）任务的首次观测结果，该任务与2014年5月9日相当的X1.6耀斑相关的壮观快速CME/日珥爆发。喷发的最大天平面速度和多普勒速度分别为1200和460 km/s。在多普勒速度上有两个喷发分量，相隔约200公里/秒：一个主要的明亮分量和一个次要的微弱分量，表明物质的分布是中空的，而不是实心的锥形。喷发涉及一个左旋螺旋结构，它正经历逆时针（自上而下）的解旋运动。有一个时间的演变，从向上喷发到向下回落小于自由落体速度和减少非热谱线宽度。我们发现了一个广泛的Mg II K/H线强度比（小于约2预期的光学薄的热发射）：最低的有史以来报道的中位数值为1.17发现的回落材料和一个非常高的值为1.63附近的日冕雨和中间值为1.53和1.41的两个喷发组件。回退材料在k/h比与多普勒速度以及线强度之间表现出强（$> 5 σ$）线性相关性。我们证明，多普勒调光散射色球发射的喷发物质可以潜在地解释这样的特点。
SDO/AIA Detection of Solar Prominence Formation within a Coronal Cavity
我们报告的第一个分析SDO/AIA观测的形成一个静止的极冠突出的冕腔。He II 304 He（log T_{max} ~ 4.8 K）数据显示，由于等离子体的垂直引流和横向输送，日珥逐渐消失，约12小时后形成新的日珥。在日珥形成之前，在冕腔的中心区域会出现明亮的发射“云”。云的峰值亮度在时间上从Fe XIV 211通道，通过Fe XII 193通道，到Fe IX 171通道逐渐移动（log T_{max}分别为6.2，6.1，5.8 K），同时高度降低。过滤器比分析估计的云在腔中的初始温度约为log T \sim 6.25 K的冷却随着时间的推移的证据。随后日珥的增长伴随着211通道中空洞的变暗。这些观测结果暗示了通过冕腔中热等离子体的原位冷凝形成日珥的可能性，支持了日冕磁通量绳中磁热对流的拟议过程。
Observations of rapidly-rotating cool stars often show coronal slingshot prominences that remove mass and angular momentum when they are ejected. The derived masses of these prominences show a scatter of some two orders of magnitude. In order to investigate if this scatter could be intrinsic, we use a full magnetic cycle of solar magnetograms to model the coronal structure and prominence distribution in a young Sun, where we scale the field strength in the magnetograms with angular velocity according to $ B \propto Ω^{-1.32} $. We reproduce both the observed prominence masses and their scatter…
In this paper, we report the multiwavelength observations of an erupting prominence and the associated CME on 13 May 2013. The event occurs behind the western limb in the field of view of SDO/AIA. The prominence is supported by a highly twisted magnetic flux rope and shows rapid rotation in the counterclockwise direction during the rising motion. The rotation of the prominence lasts for $\sim$47 minutes. The average period, angular speed, and linear speed are $\sim$806 s, $\sim$0.46 rad min$^{-1}$, and $\sim$355 km s$^{-1}$, respectively. The total twist angle reaches $\sim$7$π$, which is cons…
Spectroscopic He I 1083 nm prominence eruption observations in the middle corona with MLSO/UCoMP
Taylor University（泰勒大学）；Southwest Research Institute（西南研究所）；High Altitude Observatory, NSF National Center for Atmospheric Research（高山观测站，美国国家科学基金会国家大气研究中心）
利用MLSO/UCoMP在He I 1083 nm观测中探测日珥喷射，提供动态行为信息以改进空间天气预报。
Coronal condensation and rain are a crucial part of the mass cycle between the corona and chromosphere. In some cases, condensation and subsequent rain originate in the magnetic dips formed during magnetic reconnection. This provides a new and alternative formation mechanism for coronal rain. Until now, only off-limb, rather than on-disk, condensation events during reconnection have been reported. In this paper, employing extreme-ultraviolet (EUV) images of the Solar Terrestrial Relations Observatory (STEREO) and Solar Dynamics Observatory (SDO), we investigate the condensations facilitated by…
Determination of Acceleration from 3D Reconstruction of Coronal Mass Ejections Observed by STEREO
我们采用了三维（3D）重建技术，第一次研究6个日冕物质抛射（CME）的运动学，使用从COR1和COR2 coronagraphs上获得的双STEREO航天器的图像，也与其中三个使用的图像从极紫外成像仪（EUVI）的爆发性喷发（EP）。一个功能的EP和前缘（LE）的所有CME的识别和跟踪的图像从两个航天器，和立体重建技术被用来确定这些功能的三维坐标。真速度和加速度是从日冕物质抛射特征的真高度的时间演变来确定的。我们在三维中对日冕物质抛射运动学的研究表明，日冕物质抛射前缘通常在2R $_\{odot}$以下经历最大加速度。与耀斑和日冕物质抛射有关的日冕物质抛射的加速度剖面表现出不同的行为。虽然CME不与双折射显示出双峰加速配置文件，那些与双折射没有。在研究中，三个相关的双折射中的两个显示出高且不断上升的加速度值，其距离几乎为4R $_\{odot}$，但相应的CME LE的加速度没有显示出相同的行为，这表明两者可能并不总是由相同的机制驱动。其中一个日冕物质抛射虽然与C级耀斑有关，但却显示出异常高的加速度，超过了1500 m s $^{-2}$。因此，我们的研究结果表明，只有耀斑相关的CME经历剩余加速，这表明通量注入理论模型适用于耀斑相关的CME，但EP相关的CME应考虑不同的机制。
The first ionization potential (FIP) bias is currently used to trace the propagation of solar features ejected by the wind and solar eruptions (coronal mass ejections). The FIP bias also helps us to understand the formation of prominences, as it is a tracer for the solar origin of prominence plasma. This work aims to provide elemental composition and FIP bias in quiescent solar prominences. This is key information to link these features to remnants of solar eruptions measured in-situ within the heliosphere and to constrain the coronal or photospheric origin of prominence plasma. We used the di…
