Photospheric Magnetic Evolution in the WHI Active Regions
Photospheric Magnetic Evolution in the WHI Active Regions
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DOI：
10.1007/s11207-011-9759-9
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发表时间：
2011-03
期刊：
影响因子：
2.8
通讯作者：
B. Welsch;S. Christe;J. McTiernan
中科院分区：
文献类型：
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作者：
B. Welsch;S. Christe;J. McTiernan
利用迈克尔逊多普勒成像仪（Michelson Doppler Imager）记录的视线（LOS）磁图序列，定量地研究了全日圈间隔（WHI）期间横跨太阳盘面旋转的三个活动区的光球磁结构和演化，试图将这些活动区的光球磁特性与耀斑和日冕物质抛射（CME）联系起来。在我们的分析中使用了几种方法，从整个活动区域的规模，磁功能，超颗粒尺度，最后，到个别像素。我们计算了几个参数的磁结构和演变，以前与耀斑和CME活动，包括总无符号磁通量，磁通量附近的极性反转线，取消磁通量，“代理坡印亭通量”，和螺旋通量。为了对耀斑事件进行编目，我们使用了来自GOES和RHESSI观测的耀斑列表。通过大多数这样的措施，AR 10988应该是最耀斑和CME生产活动区，AR 10989最少。然而，观测结果与这一预期并不一致：AR 10988和10989产生了类似数量的耀斑，AR 10989也产生了一些CME。这些结果突出了目前的局限性南极洲为基础的耀斑和日冕物质抛射预测工具，仅依赖于视线光球磁数据。
Sequences of line-of-sight (LOS) magnetograms recorded by theMichelson Doppler Imagerare used to quantitatively characterize photospheric magnetic structure and evolution in three active regions that rotated across the Sun’s disk during the Whole Heliosphere Interval (WHI), in an attempt to relate the photospheric magnetic properties of these active regions to flares and coronal mass ejections (CMEs). Several approaches are used in our analysis, on scales ranging from whole active regions, to magnetic features, to supergranular scales, and, finally, to individual pixels. We calculated several parameterizations of magnetic structure and evolution that have previously been associated with flare and CME activity, including total unsigned magnetic flux, magnetic flux near polarity-inversion lines, amount of canceled flux, the “proxy Poynting flux,” and helicity flux. To catalog flare events, we used flare lists derived from both GOES and RHESSI observations. By most such measures, AR 10988 should have been the most flare- and CME-productive active region, and AR 10989 the least. Observations, however, were not consistent with this expectation: ARs 10988 and 10989 produced similar numbers of flares, and AR 10989 also produced a few CMEs. These results highlight present limitations of statistics-based flare and CME forecasting tools that rely upon line-of-sight photospheric magnetic data alone.