根据大熊座太阳天文台新太阳望远镜（NST）对太阳颗粒的观测，探讨了太阳宁静区、冕洞和活动区斑中亮点的自行。我们自动检测和跟踪亮点（BP），并推导出它们的均方位移作为时间的函数（从每个BP的出现开始）为所有可用的时间间隔。在所有三种磁场环境中，我们都发现了超扩散机制的存在，这在10-300秒的时间间隔内最为明显。通过光谱指数$γ$（均方位移光谱的斜率）测量的超扩散从谱斑区（$γ=1.48$）到宁静太阳区（$γ=1.53$）再到冕洞（$γ=1.67$）增加。我们还发现，湍流扩散系数的变化与时间和空间尺度成正比。对于最小空间尺度（22 km）和最小时间尺度（10 sec），冕洞和宁静太阳区的$^{2}$ s $^{-1}$分别为22和19 km，而对于斑区，对于最小时间尺度15 sec，$^{2}$ s $^{-1}$约为12 km。我们应用我们的BP跟踪代码的三维MHD模型数据的太阳对流（Stein等。2007），并发现超扩散与$γ=1.45$。得到了湍流扩散系数随尺度和$γ$变化的表达式。
英文摘要：
On the basis of observations of solar granulation obtained with the New Solar Telescope (NST) of Big Bear Solar Observatory, we explored proper motion of bright points (BPs) in a quiet sun area, a coronal hole, and an active region plage. We automatically detected and traced bright points (BPs) and derived their mean-squared displacements as a function of time (starting from the appearance of each BP) for all available time intervals. In all three magnetic environments, we found the presence of a super-diffusion regime, which is the most pronounced inside the time interval of 10-300 seconds. Super-diffusion, measured via the spectral index, $γ$, which is the slope of the mean-squared displacement spectrum, increases from the plage area ($γ=1.48$) to the quiet sun area ($γ=1.53$) to the coronal hole ($γ=1.67$). We also found that the coefficient of turbulent diffusion changes in direct proportion to both temporal and spatial scales. For the minimum spatial scale (22 km) and minimum time scale (10 sec), it is 22 and 19 km$^{2}$ s$^{-1}$ for the coronal hole and the quiet sun area, respectively, whereas for the plage area it is about 12 km$^{2}$ s$^{-1}$ for the minimum time scale of 15 seconds. We applied our BP tracking code to 3D MHD model data of solar convection (Stein et al. 2007) and found the super-diffusion with $γ=1.45$. An expression for the turbulent diffusion coefficient as a function of scales and $γ$ is obtained.
Flares produce sudden and permanent changes in the horizontal photospheric magnetic field. In particular flares generally produce increased magnetic shear in the photospheric field along the neutral line. Recent observations show also that flares can produce sudden photospheric motion. We present a model for the observed changes as the response of the photosphere to a large-amplitude shear Alfvén wave propagating down from the corona on either side of the neutral line. The Alfvénic front is assumed to impact the photosphere close to the neutral line first, and then successively further away wi…
Jet phenomena with a bright loop in their footpoint, called anemone jets, have been observed in the solar corona and chromosphere. These jets are formed as a consequence of magnetic reconnection, and from the scale universality of magnetohydrodynamics (MHD), it can be expected that anemone jets exist even in the solar photosphere. However, it is not necessarily apparent that jets can be generated as a result of magnetic reconnection in the photosphere, where the magnetic energy is not dominant. Furthermore, MHD waves generated from the photospheric jets could contribute to chromospheric heatin…
Context. Velocity or intensity swirls have now been shown to be widely present throughout the photosphere and chromosphere. It has been suggested that these events could contribute to the heating of the upper solar atmosphere, via exciting Alfvén pulses, which could carry significant amounts of energy. However, the conjectured necessary physical conditions for their excitation, that the magnetic field rotates co-spatially and co-temporally with the velocity field, has not been verified. Aims. We aim to understand whether photospheric velocity swirls exist co-spatially and co-temporally with ph…
The wings of Ca II H and K as photospheric diagnostics and the reliability of one-dimensional photosphere modeling
Ca II H和K线的延伸翼提供了对太阳光球和其他冷恒星的温度分层的出色诊断，这要归功于它们的LTE不透明度和源函数以及它们的大跨度形成高度。本研究的目的是校准使用的H和K翼在一维空间平均光谱的解释，并在推导每像素分层解析光谱。我使用太阳对流的多维模拟来合成H和K机翼，从这些机翼导出一维模型，就像它们被观察到一样，并将所得模型与实际模拟输入进行比较。我发现，从合成的翅膀构造的空间平均模型一般匹配的模拟平均值很好，除了最深层的光球大的热不均匀性和普朗克函数的非线性给出了很大的误差。不均匀性越大，后者越大。强网络场的存在增加了这种不均匀性。在平静的光球条件下，温度超过200 K。一维分层适合的离散结构，如造粒和小规模的磁浓度给出了令人满意的结果与错误，主要是由于陡峭的温度梯度和温度随深度的突然变化。我的结论是分层建模使用的H和K翼是一个有用的技术，太阳高分辨率观测的解释。
An active region filament studied simultaneously in the chromosphere and photosphere: I - Magnetic structure
本文对紧凑型活动区（AR）灯丝（NOAA 10781）中的矢量磁场进行了多波长、多高度的研究。我们提出了一个进化的情况下，这种灯丝。用TIP-II在包括色球He I 10830 A多重峰和光球Si I 10827 A谱线的光谱范围内获得全斯托克斯矢量。在2005年7月3日的He I吸收图像中检测到AR细丝（在我们的观测运行之前形成）。色球矢量磁场在这部分的灯丝强烈剪切，而光球场线下面有一个相反的极性配置。从7月3日到7月5日，记录了极性反转线（PIL）两侧极性的打开和关闭，类似于最近发现的Hinode看到的滑动门效应过程。7月5日，从色球层光谱中推断出一个正常的极性结构，同时在光球层中发现了与PIL对齐的强烈剪切场线。在同一数据集中，在FOV的不同部分也观察到了细丝的脊柱，并通过硅线芯清楚地映射。所推断的灯丝的矢量磁场建议磁通绳拓扑结构。此外，观测表明暗条被分成两部分，一部分位于色球层，另一部分被困在光球层。因此，只有螺旋结构的顶部才能被氦线看到。在PIL的孔隙和孤儿半影似乎是光球对应的极低的灯丝。我们认为，孤立半影形成于致密AR的非常狭窄的PIL中，是光球中通量绳的光球表现。
Two semi-automated computational approaches for spectroscopic analysis of stellar photospheres: detailed characterization at high resolution and abundance determination at medium resolution
The processes that shape the extended atmospheres of red supergiants (RSGs), heat their chromospheres, create molecular reservoirs, drive mass loss, and create dust remain poorly understood. Betelgeuse's V-band "Great Dimming" event of 2019 September /2020 February and its subsequent rapid brightening provides a rare opportunity to study these phenomena. Two different explanations have emerged to explain the dimming; new dust appeared in our line of sight attenuating the photospheric light, or a large portion of the photosphere had cooled. Here we present five years of Wing three-filter (A, B,…
Obtaining the magnetic field vector accurately in the solar atmosphere is essential for studying changes in field topology during flares and to reliably model space weather. We tackle this problem by applying various inversion methods to a confined X2.2 flare in NOAA AR 12673 on September 6, 2017, comparing the photospheric and chromospheric magnetic field vector with those from two numerical models of this event. We obtain the photospheric field from Milne-Eddington (ME) and (non-)local thermal equilibrium (non-LTE) inversions of Hinode SOT/SP Fe I 6301.5Å and 6302.5Å. The chromospheric field…
Magnetic and dynamical photospheric disturbances observed during an M3.2 solar flare
这封信报告了一组全斯托克斯光谱偏振观测在近红外He I 10830 A光谱区，涵盖前，耀斑，和耀斑后阶段的M3.2类太阳耀斑。该耀斑起源于2013年5月17日，属于活动区NOAA 11748。我们在耀斑中探测到强烈的He I 10830 A辐射。He I三重态的红色分量的峰值与连续谱的强度比约为1.86。在耀斑期间，He I Stokes V比通常较大的Si I Stokes V剖面大得多，并且出现反转。四个Stokes剖面的光球Si I反演揭示了以下几个方面：（1）耀斑相期间光球中的磁场强度比耀斑前相减小甚至消失。然而，这种下降并不是永久性的。在耀斑之后，磁场在短时间内恢复其耀斑前的配置（即，在耀斑后30分钟内）。(2)在光球中，在耀斑爆发之前，视线速度表现出规则的颗粒状向上和向下流动模式。在耀斑期间，上升气流（蓝移）控制着耀斑产生的区域。已分别推导出深光球层和高光球层中~ $10^{-3}$和~ $10^{-4}$ g cm $^{-2}$ s $^{-1}$的蒸发率，它们能在大约400秒内使色球层密度增加两倍。
Photospheric Electric Fields and Energy Fluxes in the Eruptive Active Region NOAA 11158
在不断演化的太阳活动区中，有多少电磁能量穿过光球层？随着高节奏矢量磁场观测的出现，解决这个基本问题已经变得容易处理。本文利用Kazachenko等人（2014）的“PTD-Doppler-FLCT-Ideal”（PDFI）电场反演技术对6天HMI/SDO矢量磁图和多普勒速度序列进行反演，以寻找活动区NOAA 11158的电场和坡印廷通量演化，该活动区在2011年2月15日早期产生了X2.2耀斑。我们发现光球电场范围高达$2$ V/cm。坡印廷通量的范围从$[-0.6$到$2.3]\times10^{10}$ ergs $\cdot$ cm $^{-2}$ s $^{-1}$，大部分为正值，在$[10^9$ - $10^{10}]$ ergs $\cdot$ cm $^{-2}$ s $^{-1}$范围内对能量收支的贡献最大。通过对瞬时能流的时空积分，我们发现从初始出现到X2.2耀斑爆发前，光球层上积累的总磁能为$E=10.6\times10^{32}$尔格，分别被划分为自由能和势能的$2.0$和$8.6\times10^{32}$尔格。这些估计与耀斑前非线性无力场（NLFFF）外推和最小电流电晕估计（MCC）的估计是一致的，尽管我们的方法非常不同。光球电场的这项研究表明了PDFI方法估计坡印亭通量的潜力，并打开了大门，以更定量的研究太阳光球和更现实的数据驱动的模拟日冕磁场的演变。
Magnetic flux generated and intensified by the solar dynamo emerges into the solar atmosphere, forming active regions (ARs) including sunspots. Existing theories of flux emergence suggest that the magnetic flux can rise buoyantly through the convection zone but is trapped at the photosphere, while its further rising into the atmosphere resorts to the Parker buoyancy instability. To trigger such an instability, the Lorentz force in the photosphere needs to be as large as the gas pressure gradient to hold up an extra amount of mass against gravity. This naturally results in a strongly non-force-…
One puzzling question in solar physics is the difference between elemental abundances in the photosphere and the corona. Elements with low first ionization potential (FIP) can be overabundant in the corona compared to the photosphere under certain circumstances. The same phenomenon has been observed on a handful of stars, while a few of them show the inverse effect. But not all the stars in the original sample had precise photospheric abundances derived from optical spectra, so for some the solar values were adopted. In this work we make homogeneous abundance measurements from optical spectros…
We analyze recent high resolution photospheric small-scale dynamo simulations that were computed with the MURaM radiative MHD code. We focus the analysis on newly forming downflow lanes in exploding granules since they show how weakly magnetized regions in the photosphere (center of granules) evolve into strongly magnetized regions (downflow lanes). We find that newly formed downflow lanes exhibit initially mostly a laminar converging flow that amplifies the vertical magnetic field embedded in the granule from a few 10 G to field strengths exceeding 800 G. This results in extended magnetic she…
Chromospheric and photospheric properties of sunspots as inferred from Stokes inversions under magneto-hydrostatic and non-local-thermodynamic equilibrium
Institut für Sonnenphysik（太阳物理研究所）；Institute for Solar Physics, Department of Astronomy, Stockholm University（斯德哥尔摩大学天文学系太阳物理研究所）；Leibniz-Institut für Astrophysik Potsdam (AIP)（波茨坦阿诺德·爱因斯坦天文 Leibniz 研究所）；ETH Zürich, Institute for Particle Physics and Astrophysics（苏黎世联邦理工学院粒子物理与天体物理研究所）；Istituto ricerche solari Aldo e Cele Daccò (IRSOL), Faculty of Informatics, Università della Svizzera italiana（意大利瑞士大学信息学院阿尔多和塞莱达科太阳研究所以及研究所）
Magnetic flux ropes (MFRs) rising buoyantly through the Sun's convection zone are thought to be subject to viscous forces preventing them from rising coherently. Numerous studies have suggested that MFRs require a minimum twist in order to remain coherent during their rise. Furthermore, even MFRs that get to the photosphere may be unable to successfully emerge into the corona unless they are at least moderately twisted, since the magnetic pressure gradient needs to overcome the weight of the photospheric plasma. To date, however, no lower limit has been placed on the critical minimum twist req…
Statistics of convective collapse events in the photosphere and chromosphere observed with the Hinode SOT
目标。对流坍缩是一种理论上预测的过程，它会增强太阳大气层中现有的弱磁场，Nagata等人（2008年）首次使用日之出卫星的高分辨率太阳光学望远镜（SOT）在一次事件中直接观测到了这一过程。使用同一台太空望远镜，我们对对流坍缩事件进行了统计分析。方法.我们的数据集包括高分辨率时间序列的偏振光谱扫描的两个铁线形成在低光球层和过滤器的图像在Mg I B 2和Ca II H，谱线，形成在高光球层和低色球层，分别。因此，我们能够研究对流坍缩事件对高光球层和色球层的影响。用MERLIN Milne-Eddington反演程序得到了全Stokes剖面的物理参数。结果我们发现，在所有的情况下，该事件是伴随着一个连续的亮点，几乎总是由增亮的钙II H图像。镁多普勒图在镁多普勒图的视场内发生的事件中的约四分之三中表现出强的下行流。对于49个事件中的每一个，我们确定了持续时间，最大光球下降流，场强增加和大小。我们发现事件持续时间约为10分钟，磁性元素半径约为0.43弧秒和0.35弧秒，事件发生前后，分别和高达1.65千克的磁场强度。
We investigate the morphology and temporal variability of a quiet Sun network region in different solar layers. The emission in several EUV spectral lines through both raster and slot time series, recorded by EIS/Hinode is studied along with H$α$ observations and high resolution spectropolarimetric observations of the photospheric magnetic field. The photospheric magnetic field is extrapolated up to the corona showing a multitude of large and small scale structures. We show for the first time that the smallest magnetic structures both at the network and the internetwork contribute significantl…
Oscillations in the Solar Faculae. III. The Phase Relations between Chromospheric and Photospheric LOS Velocities
对9个太阳光斑的视向速度振荡进行了分析，目的是研究色球层（He i 10830 A线）和光球层（Si i 10827 A线）5分钟振荡的位相关系。我们发现色球信号相对于光球信号的时滞在-12到100秒之间，平均约为50秒，我们认为观测到的小时滞有三种可能的解释：（1）He i 10830 A和Si i 10827 A的形成能级在光斑中的会聚，（2）光斑上方5分钟振荡传播速度的显著增加，（3）光斑上方5分钟振荡传播速度的显著增加，（4）光斑上方5分钟振荡传播速度的显著增加，（5）光斑上方5分钟振荡传播速度的显著增加。iii）驻波和行波的同时存在。
