Comparing UV/EUV line parameters and magnetic field in a quiescent prominence with tornadoes
Comparing UV/EUV line parameters and magnetic field in a quiescent prominence with tornadoes
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DOI：
10.1051/0004-6361/201730808
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发表时间：
2017-08
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影响因子：
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通讯作者：
P. Levens;N. Labrosse;Brigitte Schmieder;A. Ariste;A. Ariste;Lyndsay Fletcher
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作者：
P. Levens;N. Labrosse;Brigitte Schmieder;A. Ariste;A. Ariste;Lyndsay Fletcher
上下文理解等离子体和磁场之间的密切关系对于描述和解释观测到的太阳磁场的复杂动力学是重要的。目标。我们确定，如果一个密切的关系，等离子体和磁场参数测量在一个良好的观测日珥与高空间分辨率可以找到。我们选择了2014年7月15日从太空（IRIS，Hinode，SDO）和地面（THEMIS）观察到的日珥。我们使用2D互相关技术对数据集进行稳健的共对准。我们推导出的磁场参数从分光偏振测量的He I D3线THEMIS。比较了IRIS观测到的Mg II h线和k线的线比和视线速度与磁场强度、倾角和方位角的关系。使用Hinode/EIS Fe XII线比率计算电子密度，并与THEMIS和IRIS数据进行比较。结果我们发现镁II k/h的比率约为1.4无处不在，类似于以前发现的值在brachiences。我们还发现，磁场是最强的（约30 G），主要是在龙卷风般的日珥腿水平。k3多普勒频移被发现是+/- 10公里/秒之间的任何地方。电子密度在1.5e6 K的温度下被发现是约1 e9/cm 3。磁场参数之间没有显着的相关性，和任何其他等离子体参数从EUV光谱推断，这可以解释在本研究中使用的线的温度的巨大差异。结论.这是第一次在日珥中以高空间分辨率对等离子体和磁场参数进行详细的统计研究。我们的研究结果提供了重要的约束，在这些结构中的等离子体和磁场的未来模型。
Context. Understanding the close relationship between the plasma and the magnetic field is important to describe and explain the observed complex dynamics of solar prominences. Aims. We determine if a close relationship between plasma and magnetic field parameters measured in a well-observed solar prominence with high spatial resolution can be found. Methods. We select a prominence observed on 15 July 2014 from space (IRIS, Hinode, SDO) and from the ground (THEMIS). We perform a robust co-alignment of the data sets using a 2D cross-correlation technique. We derive the magnetic field parameters from spectropolarimetric measurements of the He I D3 line taken by THEMIS. Line ratios and line-of-sight velocities from the Mg II h and k lines observed by IRIS are compared with magnetic field strength, inclination and azimuth. Electron densities are calculated using Hinode/EIS Fe XII line ratios and also compared with THEMIS and IRIS data. Results. We find Mg II k/h ratios of around 1.4 everywhere, similar to values found previously in prominences. We also find that the magnetic field is strongest (around 30 G) and predominantly horizontal in the tornado-like legs of the prominence. The k3 Doppler shift is found to be between +/- 10 km/s everywhere. Electron densities at a temperature of 1.5e6 K are found to be around 1e9 /cm3. No significant correlations are found between the magnetic field parameters, and any of the other plasma parameters inferred from EUV spectroscopy, which may be explained by the large differences in the temperatures of the lines used in this study. Conclusions. This is the first time that a detailed statistical study of plasma and magnetic field parameters has been carried out at high spatial resolution in a prominence. Our results provide important constraints on future models of the plasma and magnetic field in these structures.