Different analyses of identical Hinode SOT/SP data of quiet-sun magnetic fields have in the past led to contradictory answers to the question of whether the angular distribution of field vectors is preferentially horizontal or vertical. These answers have been obtained by combining the measured circular and linear polarizations in different ways to derive the field inclinations. A problem with these combinations is that the circular and linear polarizations scale with field strength in profoundly different ways. Here, we avoid these problems by using an entirely different approach that is based exclusively on the fundamental symmetry properties of the transverse Zeeman effect for observations away from the disk center without any dependence on the circular polarization. Systematic errors are suppressed by the application of a doubly differential technique with the 5247-5250 Å line pair for observations with the ZIMPOL-2 imaging polarimeter on the French THEMIS telescope on Tenerife. This allows us to determine in a model- and resolution-independent way how the angular distribution of the intranetwork magnetic fields changes from being preferentially vertical in the lower and middle photosphere to become preferentially horizontal in the upper photosphere.
Recent Advances in the Exploration of the Small-Scale Structure of the Quiet Solar Atmosphere: Vortex Flows, the Horizontal Magnetic Field, and the Stokes-V Line-Ratio Method
我们回顾了（i）太阳大气中涡旋流的观测和数值模拟以及（ii）平静太阳区域水平磁场的测量。首先，我们讨论了各种表现形式的旋涡流，并强调调解漩涡运动的磁场的太阳表面附近的光球层和色球层的高层的作用。我们重新审视现有的太阳表面磁对流的模拟运行方面的旋涡流，并比较以前获得的结果。其次，我们回顾了与测量太阳宁静区磁场角分布相关的矛盾结果和问题。此外，我们回顾了斯托克斯-V-振幅比方法的线Fe I 630.15和630.25 nm。我们得出的结论是，最近发现的两个不同的人口在散点图中的这个比例不能被解释为“未塌陷”和“塌陷”的领域，但它们源于弱颗粒磁场和弱冠层场位于颗粒之间的边界和粒间空间。基于新的模拟运行，我们重申了先前的研究结果的水平场分量的优势超过垂直的，特别是在上层光球和色球层的底部。
Horizontal Magnetic Fields Dominate the Weak Field Quiet Sun in Sunrise III Observations. Evidence from Traditional and Transformer-Based Inversions
Queen’s University Belfast（贝尔法斯特女王大学）；Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉帕鲁纳大学）；Max-Planck-Institut für Sonnensystemforschung（马克斯·普朗克太阳系统研究所）；Instituto de Astrofísica de Andalucía, CSIC（安达卢西亚天体物理研究所，西班牙高等科学研究委员会）；Spanish Space Solar Physics Consortium（西班牙空间太阳物理学联盟）；National Astronomical Observatory of Japan（日本国立天文台）；The University of Tokyo（东京大学）；The Graduate University for Advanced Studies (SOKENDAI)（高级研究大学院大学）
While the quiet Sun magnetic field shows only little variation with the solar cycle, long-term variations cannot be completely ruled out from first principles. We investigate the potential effect of quiet Sun magnetism on spectral solar irradiance through a series of small-scale dynamo simulations with zero vertical flux imbalance ($\langle B_z\rangle=0$) and varying levels of small-scale magnetic field strength, and one weak network case with an additional flux imbalance corresponding to a flux density of $\langle B_z\rangle=100$ G. From these setups we compute the dependence of the outgoing …
Time series of high resolution photospheric spectra in a quiet region of the Sun. II. Analysis of the variation of physical quantities of granular structures
We compare horizontal velocities, vertical magnetic fields and evolution of trees of fragmenting granules (TFG, also named families of granules) derived in the quiet Sun at disk center from observations at solar minimum and maximum of the Solar Optical Telescope (SOT on board Hinode) and results of a recent 3D numerical simulation of the magneto-convection. We used 24-hour sequences of a 2D field of view (FOV) with high spatial and temporal resolution recorded by the SOT Broad band Filter Imager (BFI) and Narrow band Filter Imager (NFI). TFG were evidenced by segmentation and labeling of conti…
Spatial distribution and statistical properties of small-scale convective vortex-like motions in a quiet Sun region
本文分析了位于拉帕尔马的瑞典1米太阳望远镜对宁静的太阳网间区域的高分辨率观测。我们通过计算时间序列图像上小尺度结构的水平自行来确定太阳光球区小尺度涡旋运动的位置。这些等离子体对流驱动的漩涡运动与以下两个方面有关：（1）下降气流（通常解释为对应于等离子体冷却并因此返回到可见光球层以下的内部的位置），以及（2）水平速度矢量收敛到中心点。下沉核被证明是被动浮子追踪等离子体流向每个漩涡中心的最终目的地。对于这里分析的两个时间序列，我们确定这些事件的发生分别为1.4 x 10^（-3）和1.6 x 10^（-3）涡旋Mm^（-2）min^（-1）。
Vector Magnetic Fields and Current Helicities in Coronal Holes and Quiet Regions
在太阳光球层中，冕洞的许多性质是未知的，特别是矢量磁场。利用\emph{Hinode}的观测资料，我们首次研究了两个CH中的矢量磁场、电流密度和电流螺旋度，并与两个正常安静区（QR）进行了比较。我们发现，在CH和QR，大电流螺旋度所在的地区主要是同空间的强大的垂直和水平场元素的形状和位置。在CH中，水平磁场、倾角、电流密度和电流螺旋度都大于QR中的水平磁场、倾角、电流密度和电流螺旋度。平均垂直电流密度和电流螺旋度，在所有观察到的地区，包括CH和QR平均，分别约为0.008 A m $^{-2}$和0.005 G $^{2}$ m $^{-1}$。垂直场强于100 G的磁通量集中区的平均电流密度高达0.012 $\pm$ 0.001 A m $^{-2}$，与耀斑活动区的平均电流密度一致。我们的结果意味着，无论是在CH和QR的磁场，特别是强磁场是非势。
We investigate a region of the quiet solar photosphere exhibiting three-lobed Stokes V profiles in the Fe I spectral line at 15648 Angstroem. The data were acquired with the GRIS spectropolarimeter attached to the GREGOR telescope. We aim at investigating the thermal, kinematic and magnetic properties of the atmosphere responsible for these measured complex signals. The SIR inversion code is employed to retrieve the physical parameters of the lower solar photosphere from the observed polarization signals. We follow two different approaches. On the one hand, we consider that the multi-lobe circ…
Based on calculations of the Stokes parameters for the Holweger-Mliller model atmosphere, we study sensitivity of the Fe I 525.02 nm line to some kinds of vertical and horizontal magnetic field inhomogeneity. A noticeable asymmetry is shown to appear in the V profile peaks when the vertical gradient is -0.4 mT/km, which is typical of some theoretical flux tube models. The asymmetry is most pronounced in a pure longitudinal magnetic field and at a low macroturbulent velocity. A similar effect is observed for the Q profile in nonlongitudinal fields as well. The Fe I 525.02 nm line is sensitive a…
The quiet Sun exhibits a wealth of magnetic activities that are fundamental for our understanding of solar and astrophysical magnetism. The magnetic fields in the quiet Sun are observed to evolve coherently, interacting with each other to form distinguished structures as they are advected by the horizontal photospheric flows. We study coherent structures in photospheric flows in a region of quiet Sun consisted of supergranules. Supergranular turbulence is investigated by detecting hyperbolic and elliptic Lagrangian coherent structures (LCS) using the horizontal velocity fields derived from Hin…
Magnetic reconnection in the quiet Sun is a phenomenon that is consistently observed, and it has recently become feasible to simulate via 3D numerical models of realistically stratified and convection-driven reconnection. We aim to illustrate ways by which quiet Sun fields may contribute to solar atmospheric heating via magnetic reconnection that is driven by convective motion. We also aim to compare our stratified model to earlier idealized coronal models in terms of reconnection drivers and topological conditions. We analyzed a simulation of the quiet Sun in which a complex coronal magnetic …
The electromagnetic energy flux in the lower atmosphere of the Sun is a key tool to describe the energy balance of the solar atmosphere. Current investigations on energy flux in the solar atmosphere focus primarily on the vertical electromagnetic flux through the photosphere, ignoring the Poynting flux in other directions and its possible contributions to local heating. Based on a realistic Bifrost simulation of a quiet-Sun (coronal hole) atmosphere, we find that the total electromagnetic energy flux in the photosphere occurs mainly parallel to the photosphere, concentrating in small regions a…
Structure and Dynamics of Isolated Internetwork Ca II H Bright Points Observed by Sunrise
我们的目标是改善我们的图片在安静的太阳互联网的低色球层通过调查的强度，水平速度，大小和寿命的变化小亮点（BPs;直径小于0.3弧秒）观察到的Ca II H 3968通带沿其磁场参数，来自光球磁图。对从太阳表面空间分辨率约为100公里的“日出”球载太阳望远镜获得的盘心静日观测的若干高质量时间序列进行了分析，以研究在Ca II H通带观测到的BPs动态及其对光球矢量磁图信号的依赖性。参数，如水平速度，直径，强度和寿命直方图的孤立的互联网和磁性钙II H BP。平均值分别为2.2 km/s、0.2 arcsec（150 km）、1.48平均Ca II H宁静太阳和673 sec。有趣的是，BPs的亮度和水平速度是反相关的。大偏移（脉冲）的水平速度，高达15公里/秒，目前在大多数BP的轨迹。这可能激发出进入色球层甚至日冕的扭折波，我们估计扭折波携带的能量通量为310 W/m^2，足以加热上层，尽管只是少量的。稳定的观测条件的日出和我们的技术，用于识别和跟踪BP，使我们能够确定可靠的参数，这些功能在互联网。因此，我们发现，例如，它们的寿命比我们之前认为的要长得多大的速度也是可靠的，并可能激发扭结波。虽然这些波（勉强）能量足以加热安静的日冕，但我们预计来自网络中较大的磁性元素以及部分互联网络的大量额外贡献。
A giant solar filament was visible on the solar surface from 2011 Nov. 8-23. The filament stretched over more than half a solar diameter. Multiwavelength data from the SDO instrument AIA (171, 193, 304, and 211Å) were used to examine counter-streaming flows within the spine of the filament. H$α$ images from the Kanzelhöhe Solar Observatory provided context information. We apply local correlation tracking (LCT) to a two-hour time series on 2011 Nov. 16 of the AIA images to derive horizontal flow velocities of the filament. To enhance the contrast of the AIA images, noise adaptive fuzzy equaliza…
