Prominence fine structures in a magnetic equilibrium: Two-dimensional models with multilevel radiative transfer
Prominence fine structures in a magnetic equilibrium: Two-dimensional models with multilevel radiative transfer
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DOI：
10.1051/0004-6361:20010926
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发表时间：
2001-09
影响因子：
6.5
通讯作者：
P. Heinzel;U. Anzer
中科院分区：
文献类型：
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作者：
P. Heinzel;U. Anzer
在本文中，我们建立了处于磁流体静力学(MHS)平衡状态的垂直日冕线的理论模型。这些模型是完全二维的(2D)，并采取垂直无限的线的形式悬挂在水平磁场中。当中心冷却部分被日冕-日冕过渡区(PCTR)包围时，给出了这种2D磁沉结构的典型例子。我们显示了压力、密度和温度的二维变化。虽然压力变化遵循MHS平衡，但动力学温度是由经验确定的。作为下一步，我们解决了这种线状结构中的二维多能级非LTE传输问题，以预测出射氢谱的空间变化。结果表明，经过部分重分布处理的氢Lyman谱线的强度在空间上有明显的变化，沿磁场谱线和跨磁场谱线的谱线轮廓存在着重要的差异。我们还讨论了这些强度变化与最近的SOHO/SUMER日冕观测结果的比较，即我们展示了低于仪器分辨率的精细结构线上的线型平均的影响。最后，我们对未来的建模和观测提出了一些建议。
In this paper we construct theoretical models for vertical prominence threads which are in magnetohydrostatic (MHS) equilibrium. These models are fully two-dimensional (2D) and take the form of vertically infinite threads hanging in a horizontal magnetic field. A typical example of such a 2D magnetic-dip structure is shown for the case when the central cool parts are surrounded by the prominence-corona transition region (PCTR). We display 2D variations of the pressure, density and temperature. While the pressure variations follow from the MHS equilibrium, the kinetic temperature was specified empirically. As a next step, we have solved the 2D multilevel non-LTE transfer problem in such thread-like structures, in order to predict the spatial variations of the emergent hydrogen spectrum. It is demonstrated that the hydrogen Lyman lines (treated with partial redistribution) show significant spatial variations of the intensity and that an important difference exists between the line profiles emergent along and across the magnetic field lines. We also discuss how these intensity variations compare to recent SOHO/SUMER prominence observations, namely we show the effects of line-profile averaging over the fine-structure threads which are below the instrumental resolution. Finally we make some suggestions for future modelling and observations.