The vector magnetic field characteristics of superactive regions (SARs) hold the key for understanding why SARs are extremely active and provide the guidance in space weather prediction. We aim to quantify the characteristics of SARs using the vector magnetograms taken by the Solar Magnetic Field Telescope at Huairou Solar Observatory Station. The vector magnetic field characteristics of 14 SARs in solar cycles 22 and 23 were analyzed using the following four parameters: 1) the magnetic flux imbalance between opposite polarities, 2) the total photospheric free magnetic energy, 3) the length of the magnetic neutral line with its steep horizontal magnetic gradient, and 4) the area with strong magnetic shear. Furthermore, we selected another eight large and inactive active regions (ARs), which are called fallow ARs (FARs), to compare them with the SARs. We found that most of the SARs have a net magnetic flux higher than 7.0\times10^21 Mx, a total photospheric free magnetic energy higher than 1.0\times10^24 erg/cm, a magnetic neutral line with a steep horizontal magnetic gradient (\geq 300 G/Mm) longer than 30 Mm, and an area with strong magnetic shear (shear angle \geq 80\degree) greater than 100 Mm^2. In contrast, the values of these parameters for the FARs are mostly very low. The Pearson \c{hi}2 test was used to examine the significance of the difference between the SARs and FARs, and the results indicate that these two types of ARs can be fairly distinguished by each of these parameters. The significance levels are 99.55%, 99.98%, 99.98%, and 99.96%, respectively. However, no single parameter can distinguish them perfectly. Therefore we propose a composite index based on these parameters, and find that the distinction between the two types of ARs is also significant with a significance level of 99.96%. These results are useful for a better physical understanding of the SAR and FAR
Quantifying the Difference Between the Flux-Tube Expansion Factor at the Source Surface and at the Alfvén Surface Using A Global MHD Model for the Solar Wind
Quantifying the Anisotropy and Solar Cycle Dependence of "$1/f$" Solar Wind Fluctuations Observed by Ace
演变中的太阳风的功率谱显示了在较高频率的湍流波动的惯性范围和较低频率的“$1/f$“状区域之间的谱断裂的证据。在$\sim 1$ AU的黄道面上,这种破裂大约发生在几个小时的时间尺度上,并在速度和磁场分量的功率谱中观察到。“$1/f$“的能量范围比惯性范围更直接的日冕起源,并携带复杂的太阳日冕磁场结构的签名,并在太阳光球的脚点搅拌。为了量化的标度特性,我们使用通用的统计方法,如广义结构函数和PDF,专注于太阳周期的依赖性和各向异性的背景磁场。我们提出了结构函数分析的磁场和速度场的波动,使用一种新的技术来分解的波动方向平行和垂直于平均本地背景磁场。虽然磁场接近“$1/f$“,我们表明,速度场是“$1/f^α$“与$α\neq1$。对于速度,$α$的值在平行和垂直波动之间变化,并随太阳活动周期变化。$α$也随太阳风速度而变化。我们已经研究了快速、安静的太阳风中的PDF,有趣的是,虽然平行和垂直是不同的,但${\boldmath$ B $}$场和速度都显示出相同的垂直波动PDF,这接近于伽马或逆Gumbel。这些结果指出了日冕中不同的物理过程,以及它们映射到太阳风中的过程。得到的标度指数约束这些过程的模型。
Multi-Stranded Coronal Loops: Quantifying Strand Number and Heating Frequency from Simulated Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) Observations
A spectroscopic survey of infrared 1-4μm spectra in regions of prominent solar coronal emission lines of Fe XIII, Si X, and Si IX
红外太阳光谱包含有关太阳的大量物理数据,目前正在利用现代探测器和新的地面太阳望远镜技术进行探索。其中一种仪器将是丹尼尔K。Inouye太阳望远镜将能够对具有完整Stokes I,Q,U和V偏振状态的微弱红外日冕光谱进行灵敏成像。在星系和日冕中观测到了高度电离的磁偶极发射线。要量化光谱反演程序的准确性,需要对观测进行精确的光谱校准。对突出的磁偶极线周围的光谱进行仔细的解释对于导出物理参数,特别是对于量化DKIST的离边日冕观测是必不可少的。在这项工作中,我们的目标是提供一个分析的红外日冕发射线周围的Fe XIII 1074.68 nm,Fe XIII 1079.79 nm,Si X 1430.10 nm,和Si IX 3934.34 nm,与确定太阳光球线和大地线的目标相一致,这将有助于从四套太阳光球和大地线中产生可靠的反演和数据产品。太阳日冕观测这些产出将被纳入处理管道,以产生2级科学就绪数据,提供给DKIST观察员。
Quantifying the relationship between Moreton-Ramsey waves and "EIT waves" using observations of 4 homologous wave events
太阳大气中自由传播的全球波通常使用极紫外线通带(EUV或“EIT波”)观测,而在H-α(莫顿-拉姆齐波)中则不太规律。尽管经过数十年的研究,EUV和Moreton-Ramsey波的联合观测仍然很少见,这使得量化这些现象之间联系的努力变得复杂。我们提出了四个同源的全球波的观测,起源于同一个活动区域之间的2014年3月28日至30日,并使用EUV和H-α数据观察。太阳动力学天文台观测到了每一个全球极紫外波,并使用全球振荡网络组(GONG)网络确定了相关的莫顿-拉姆齐波。所有的全球波都表现出高的初始速度(例如,842-1388 km s $^{-1}$(在193 A通带中)和强减速(例如,-1437 - -782 m s $^{-2}$在193 A通带)在每个EUV通带的研究,EUV波运动学超过莫顿-拉姆齐波。使用差分发射测量和强度变化技术估计每个全球波的密度压缩比,两者都表明所观察到的波是弱冲击,快磁声马赫数略大于1。这表明,根据目前的模型,全球日冕波不足以产生莫顿-拉姆齐波,这表明这些观测结果的另一种解释。相反,我们的结论是,全球波的演变受到周围的日冕磁场的限制,在每一种情况下,产生一个向下的角度波前传播向北太阳极扰动色球层,并观察到作为莫顿-拉姆齐波。
Quantifying the effect of passband on observations in the Ca II K line
Max-Planck-Institut für Sonnensystemforschung(马克斯·普朗克太阳系统研究所);Grupo de Estudios en Heliofísica de Mendoza, CONICET, Universidad de Mendoza(门多萨日物理研究组,阿根廷国家科学研究委员会,门多萨大学);INAF Osservatorio Astronomico di Roma(意大利国家天体物理研究所罗马天文台);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)
利用Sunrise III任务的高分辨率观测,通过模拟不同通带和空间分辨率,建立经验对比度-对比度关系(幂律形式),为历史与现代Ca II K观测构建一致的长时序太阳活动记录提供基础。
Quantifying Properties of Photospheric Magnetic Cancellations in the Quiet Sun Internetwork
我们分析了瑞典1米太阳望远镜的分光偏振数据,以研究安静的太阳光球中小尺度磁抵消的物理特性。具体来说,我们看了完整的斯托克斯偏振配置文件沿Fe I 557.6 nm和Fe I 630.1 nm线测量的CRISP成像光谱偏振仪(CRISP)研究时间演变的视线(LOS)磁场在42.5分钟的安静的太阳演变。从这个磁图序列中,我们直观地识别出38个抵消事件。然后,我们使用另一种特征跟踪算法(YAFTA)来表征这些磁抵消的物理特性。我们发现,在每个事件中,磁通量的平均$1.6\times10^{16}$ Mx被抵消,平均抵消率为$3.8\times10^{14}$ Mx s $^{-1}$。推导出的抵消通量与强下行流有关,平均速度为$V_\mathrm{LOS}\approx1.1$ km s $^{-1}$。我们的研究结果表明,每个事件的平均寿命是$9.2$分钟,平均$44.8\%$的初始磁通被取消。我们对磁通量的估计提供了一个下限,因为所研究的磁抵消事件具有非常接近仪器噪声水平的磁场值。我们没有观察到水平磁场的取消网站,因此不能得出结论,事件是否相关的结构,可能会导致磁重联。
Multi-spacecraft constraints on relativistic solar energetic particle transport in the widespread 28 October 2021 event
National & Kapodistrian University of Athens(雅典国立卡波迪斯特里安大学);Institute for the Management of Information Systems, "Athena" Research Center(雅典研究中心信息管理研究所);Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing (IAASARS), National Observatory of Athens(雅典国家天文台天文学、天体物理学、空间应用和遥感研究所);Space Research Laboratory, University of Turku(图尔库大学空间研究实验室);Centre for Space Research, North-West University(西北大学空间研究中心);National Institute for Theoretical and Computational Sciences (NITheCS)(国家理论与计算科学研究所);The Johns Hopkins University Applied Physics Laboratory(约翰斯·霍普金斯大学应用物理实验室)
Half-year Evolution of a Decaying Solar Active Region and Peripheral Dimming Regions
School of Earth and Space Sciences, Peking University(北京大学地球与空间科学学院);State Key Laboratory of Solar Activity and Space Weather, National Space Science Center, Chinese Academy of Sciences(中国科学院国家空间科学中心太阳活动与空间天气重点实验室)
本研究通过多波长观测分析了太阳活跃区域NOAA AR 12738六个月内衰减过程,揭示了外围变暗区域的热亏损机制及其对日冕磁重构的影响。
Metallicity and Temperature Indicators in M dwarf K band Spectra: Testing New & Updated Calibrations With Observations of 133 Solar Neighborhood M dwarfs
Towards a live homogeneous database of solar active regions based on SOHO/MDI and SDO/HMI synoptic magnetograms. I. Automatic detection and calibration
Using in-situ solar-wind observations to generate inner-boundary conditions to outer-heliosphere simulations, 1: Dynamic time warping applied to synthetic observations
Dominance of Bursty over Steady Heating of the 4--8 MK Coronal Plasma in a Solar Active Region: Quantification using Maps of Minimum, Maximum, and Average Brightness
Hinode EIS Observations of Plasma Composition Evolution and Radiative Cooling of Solar Flare Loops
INAF Osservatorio Astronomico di Roma(罗马天文台);NASA Goddard Space Flight Center(NASA戈达德太空飞行中心);Universities Space Research Association(大学空间研究协会);Mullard Space Science Laboratory, University College London(伦敦大学学院穆拉德空间科学实验室);Northumbria University(诺森比亚大学);Computational Physics Inc.(计算物理公司);Dublin City University(都柏林城市大学);Dublin Institute for Advanced Studies(都柏林高等研究院);Konkoly Observatory(孔科利天文台)
Quantifying the Propagation of Fast Coronal Mass Ejections from the Sun to Interplanetary Space Combining Remote Sensing and Multi-Point in-situ Observations
Modeling hot, anisotropic ion beams in the solar wind motivated by the Parker Solar Probe observations near perihelia
The Catholic University of America(美国天主教大学);Heliophysics Science Division, NASA Goddard Space Flight Center(NASA戈达德太空飞行中心日球物理科学部);Tel Aviv University(特拉维夫大学);Goddard Planetary Heliophysics Institute, University of Maryland(马里兰大学戈达德行星日球物理研究所);Johns Hopkins University Applied Physics Laboratory(约翰斯·霍普金斯大学应用物理实验室);Physics & Astronomy Department, Georgia State University(佐治亚州立大学物理与天文系);Lunar and Planetary Laboratory, University of Arizona(亚利桑那大学月球与行星实验室)
Random Walk and Trapping of Interplanetary Magnetic Field Lines: Global Simulation, Magnetic Connectivity, and Implications for Solar Energetic Particles
Turbulent Diffusion of Magnetic Field Lines in the Heliosphere
Centre for Space Research, North-West University(西北大学空间研究中心);National Institute for Theoretical and Computational Physics (NITheCS)(理论与计算物理国家研究所);State Key Laboratory of Lunar and Planetary Sciences and CNSA Macau Center for Space Exploration and Science, Macau University of Science and Technology(澳门科技大学月球与行星科学国家重点实验室及中国航天局澳门太空探索与科学中心)