Global Coronal Equilibria with Solar Wind Outflow
Global Coronal Equilibria with Solar Wind Outflow
复制标题
太阳风流出的全球日冕平衡
作者：
O. Rice;A. Yeates
考虑到太阳光球表面已知的径向磁场分布，存在计算日冕中潜在磁场的成熟方法。这种势场通常用作太阳风模型的输入，并初始化日冕和日光层磁场的磁摩擦或完整磁流体动力学模拟。我们描述了一种改进的磁场模型，该模型计算具有施加的太阳风剖面的磁摩擦平衡（可以是帕克的太阳风解决方案，或任何合理的等效方案）。这些“流出场”似乎比势场更接近真实的日冕磁场，计算时间相似，并且无需施加人造源表面。因此，它们为初始化时间演化模拟或日光层磁场建模提供了势场模型的实用替代方案。我们给出了球坐标系中的开源 Python 实现，并将该模型应用于太阳周期 24 的数据。与势场模型相比，流出往往会增加开放磁通量，从而减少了与现场观测的众所周知的差异。
Given a known radial magnetic field distribution on the Sun’s photospheric surface, there exist well-established methods for computing a potential magnetic field in the corona above. Such potential fields are routinely used as input to solar wind models, and to initialize magneto-frictional or full magnetohydrodynamic simulations of the coronal and heliospheric magnetic fields. We describe an improved magnetic field model that calculates a magneto-frictional equilibrium with an imposed solar wind profile (which can be Parker’s solar wind solution, or any reasonable equivalent). These “outflow fields” appear to approximate the real coronal magnetic field more closely than a potential field, take a similar time to compute, and avoid the need to impose an artificial source surface. Thus they provide a practical alternative to the potential field model for initializing time-evolving simulations or modeling the heliospheric magnetic field. We give an open-source Python implementation in spherical coordinates and apply the model to data from solar cycle 24. The outflow tends to increase the open magnetic flux compared to the potential field model, reducing the well-known discrepancy with in situ observations.
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影响因子：
2.8
作者：
P. Bhowmik;Anthony Yeates
通讯作者：
P. Bhowmik;Anthony Yeates
影响因子：
2.8
作者：
T. Wiegelmann;T. Neukirch;D. Nickeler;I. Chifu
通讯作者：
T. Wiegelmann;T. Neukirch;D. Nickeler;I. Chifu
DOI：
10.3847/1538-4357/aaec7c
发表时间：
2018
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Mackay D
通讯作者：
Mackay D
恒星日冕对差异旋转和通量出现的响应
影响因子：
4.8
作者：
Gibb G
通讯作者：
Gibb G