The Influence of Faraday Rotation on the Vertical Electric Current Density
The Influence of Faraday Rotation on the Vertical Electric Current Density
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DOI：
10.1086/508511
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发表时间：
2006-09
期刊：
影响因子：
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通讯作者：
J. Su;H. -. Zhang;Y. Y. Deng-Y.;X. Mao;Y. Gao;G. Lin
中科院分区：
文献类型：
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作者：
J. Su;H. -. Zhang;Y. Y. Deng-Y.;X. Mao;Y. Gao;G. Lin
本文分析了法拉第旋转对太阳活动区垂直电流密度的影响。根据fei5324.19 Å线在太阳盘中心的Stokes参数传递方程的数值解，导出了法拉第旋转引起的垂直电流随波长的变化。模拟结果表明，法拉第旋转改变了线中心垂直电流的符号和大小，但只改变了线远翼垂直电流的大小。在一个简单的太阳黑子上选定的位置，观测到的垂直电流随波长的变化与模型进行了比较。我们发现，当在fei5324.19 Å线中心附近观测时，方位角旋转是显著的：垂直电流的符号变化发生在约13.5%的选定位置，其中约26%的位置垂直电流的幅度增加超过“真实”值的100%。我们还对法拉第旋转的矢量磁场观测作了初步的修正。特别是对于NOAA AR 10162，法拉第旋转似乎对垂直电流有显著影响。
In this Letter we analyze the effects of Faraday rotation on the vertical electric current density in solar active regions. On the basis of the numerical solutions of the transfer equations of Stokes parameters for the Fe I 5324.19 Å line at the solar disk center, we derive the variations of the vertical current with wavelengths, which are caused by Faraday rotation. The simulations show that Faraday rotation changes both the sign and the magnitude of the vertical current at line center, but it changes only its magnitude at the far wings of the line. At the selected locations on a simple sunspot, the observed variations of the vertical current with wavelengths are compared with the model. We find that the azimuth rotation is significant when observations are taken near the center of the Fe I 5324.19 Å line: the sign change of the vertical current occurs in about 13.5% of the total selected locations, and in about 26% of those the magnitude increases the vertical current more than 100% of the "real" value. We also make a preliminary attempt to correct a case of the vector magnetic field observations for Faraday rotation. For NOAA AR 10162, in particular, it appears that Faraday rotation has a significant effect on the vertical current.