Thermodynamic Structure of the Solar Corona: Tomographic Reconstructions and MHD Modeling
Thermodynamic Structure of the Solar Corona: Tomographic Reconstructions and MHD Modeling
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日冕的热力学结构：断层扫描重建和 MHD 建模
DOI：
10.1007/s11207-020-01641-z
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发表时间：
2020
期刊：
影响因子：
2.8
通讯作者：
R. Frazin
中科院分区：
文献类型：
--
作者：
D. Lloveras;A. M. Vásquez;F. Nuevo;C. Mac Cormack;N. Sachdeva;W. Manchester;B. van der Holst;R. Frazin
通过层析重建和磁流体动力学模拟，研究了静止内日冕(R<；1.25R⊙$r<；1.25)的电子密度和温度的全球三维结构。在它们的最新版本中，我们使用了差分发射测量层析成像(DEMT)和阿尔芬波太阳模型(AWSoM)。从太阳周期(SC)23和24之间的太阳极小值和SC 24的下降阶段中选择了两个目标自转。我们详细定量地报道了流光带核心层和外层以及高纬冕洞(CH)的三维热力学结构，正如DEMT分析所揭示的那样。我们报告了流光带内存在两种类型的结构，即随高度下降/增加温度的环路(称为向下/向上环路)，这在以前的DEMT研究中首次报道。我们还估计了保持这些结构稳定所需的热能通量，发现其量级为105 erg cm−2 S−1$10^{5}~\TEXT{ERG}，\TEXT{cm}^{-2}\，\TEXT{S}^{-1}$，与以前的DEMT和光谱研究一致。我们讨论了这些发现如何与阿尔芬波的日冕耗散相一致。我们比较了DEMT和AWSOM在不同磁结构下的3D结果。我们发现，这两种技术的产品之间的一致性是到目前为止最好的，总体一致性≲为20%，这取决于目标的旋转和特定的日冕区域。然而，在其当前的实现中，ASWsoM模型不能重现下行循环。此外，在太阳风的快分量和慢分量的源区，AWSoM模型的电子密度随着纬度的增加而增加，与DEMT重建中观察到的趋势相反。
We carry out a study of the global three-dimensional (3D) structure of the electron density and temperature of the quiescent inner solar corona ( r < 1.25 R ⊙ $r<1.25\,\mathrm{R_{\odot }}$ ) by means of tomographic reconstructions and magnetohydrodynamic simulations. We use differential emission measure tomography (DEMT) and the Alfvén Wave Solar Model (AWSoM), in their latest versions. Two target rotations were selected from the solar minimum between Solar Cycles (SCs) 23 and 24 and the declining phase of SC 24. We report in quantitative detail on the 3D thermodynamic structure of the core and outer layers of the streamer belt, and of the high latitude coronal holes (CH), as revealed by the DEMT analysis. We report on the presence of two types of structures within the streamer belt, loops with temperature decreasing/increasing with height (dubbed down/up loops), as reported first in previous DEMT studies. We also estimate the heating energy flux required at the coronal base to keep these structures stable, found to be of order 10 5 erg cm − 2 s − 1 $10^{5}~\text{erg}\,\text{cm}^{-2}\,\text{s}^{-1}$ , consistently with previous DEMT and spectroscopic studies. We discuss how these findings are consistent with coronal dissipation of Alfvén waves. We compare the 3D results of DEMT and AWSoM in distinct magnetic structures. We show that the agreement between the products of both techniques is the best so far, with an overall agreement ≲ 20 % $\lesssim 20\%$ , depending on the target rotation and the specific coronal region. In its current implementation the ASWsoM model cannot reproduce down loops though. Also, in the source region of the fast and slow components of the solar wind, the electron density of the AWSoM model increases with latitude, opposite to the trend observed in DEMT reconstructions.
对帕克太阳探测器第一次相遇的预测
DOI：
10.3847/2041-8213/ab04a5
发表时间：
2019
期刊：
The Astrophysical Journal
影响因子：
--
作者：
van der Holst, B.;IV, W. B.;Klein, K. G.;Kasper, J. C.
通讯作者：
Kasper, J. C.