We study vortex dynamics in the solar atmosphere by employing and deriving the analytical evolution equations of two vortex identification criteria. The two criteria used are vorticity and the swirling strength. Vorticity can be biased in the presence of shear flows, but its dynamical equation is well known; the swirling strength is a more precise criterion for the identification of vortical flows, but its evolution equation is not known yet. Therefore, we explore the possibility of deriving a dynamical equation for the swirling strength. We then apply the two equations to analyze radiative MHD simulations of the solar atmosphere produced with the CO5BOLD code. We present a detailed review of the swirling strength criterion and the mathematical derivation of its evolution equation. This equation did not exist in the literature before and it constitutes a novel tool that is suitable for the analysis of a wide range of problems in (magneto-)hydrodynamics. By applying this equation to numerical models, we find that hydrodynamical and magnetic baroclinicities are the driving physical processes responsible for vortex generation in the convection zone and the photosphere. Higher up in the chromosphere, the magnetic terms alone dominate. Moreover, we find that the swirling strength is produced at small scales in a chaotic fashion, especially inside magnetic flux concentrations. The swirling strength represents an appropriate criterion for the identification of vortices in turbulent flows, such as those in the solar atmosphere. Moreover, its evolution equation, which is derived in this paper, is pivotal for obtaining precise information about the dynamics of these vortices and the physical mechanisms responsible for their production and evolution. Since this equation is available, the swirling strength is now the ideal quantity to study the dynamics of vortices in (magneto-)hydrodynamics.
Solar vortex detection methods in MHD simulations: impact of magnetic field and spatial resolution
Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Departamento de Astrofísica, Universidad de La Laguna（拉古纳大学天体物理学系）；Institute of Chemical Kinetics and Combustion SB RAS（俄罗斯科学院西伯利亚分院化学动力学与燃烧研究所）
Connectivity between the solar photosphere and chromosphere in a vortical structure. Observations of multi-phase, small-scale magnetic field amplification
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。
Solar Vortices as Conduits for Magnetoacoustic Waves: Multi-Layer Coupling and Their Role in Atmospheric Heating
University of Sheffield（谢菲尔德大学）；National Observatory of Athens（雅典国家天文台）；Northumbria University（诺森比亚大学）；Queen’s University Belfast（贝尔法斯特女王大学）；University of Oslo（奥斯陆大学）
The Polar Vortex Hypothesis: Evolving, Spectrally Distinct Polar Regions Explain Short- and Long-term Light Curve Evolution and Color-Inclination Trends in Brown Dwarfs and Giant Exoplanets
Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. II- Numerical aspects
横向磁流体动力学（MHD）波在太阳大气中无处不在，可能是产生太阳百万度外层大气的原因。然而，这些波的耗散过程和加热的直接证据仍然难以捉摸。通过先进的数值模拟结合适当的正演模拟的日珥通量管，我们提供了观测到的签名的横向MHD波在日珥等离子体。我们发现，这些签名的特点是线程状的子结构，强大的横向动力学相干性，一个出的相位之间的差异平面的天空运动和LOS速度，以及增强线加宽和加热周围的大部分通量管。共振吸收和开尔文-亥姆霍兹不稳定性（KHI）之间的复杂组合发生，其中KHI从共振层提取能量并通过涡旋和电流片耗散能量，涡旋和电流片迅速退化为湍流。产生边界的向内扩大，其中湍流保持来自共振的特征动力学，因此保证共振印记的可检测性。我们通过协调的Hinode和IRIS观测表明，随附论文（Okamoto et al. 2015）中描述的特征与数值结果匹配良好。
