论文标题
通过磁场的垂直组件对Umbra-Penumbra边界的表征 - 分析Gregor红外光谱仪的地面数据
Characterization of the umbra-penumbra boundary by the vertical component of the magnetic field -- Analysis of ground-based data from the GREGOR Infrared Spectrograph
论文作者
论文摘要
在HINODE/SP数据的统计研究中，发现磁场的垂直组件（$ b_ \ perp $）在稳定黑子的Umbra-Penumbra边界处达到恒定值。这项工作的目的是验证来自近红外波长中的基于地面数据的umbra-penumbra边界上$ b_ \ perp $的恒定值的存在，并确定其对Gregor红外光谱仪（GRIS）数据的值。这是关于Jurcak标准的首次统计研究，并具有基于地面的数据，我们将其与HINODE和HMI数据的结果进行了比较。从gris档案（sdc.leibniz-kis.de）中选择了来自gris狭缝谱图的11个光谱数据集。包括偏光散射校正在内的SIR反转用于使用Fe 1564.8和1566.2 nm线生成磁场矢量的地图。对于11个数据集，分析了Umbra-Penumbra边界沿umbra-Penumbra边界的平均值。计算出结果$ b_ \ perp^{\ rm const} $值和强度的轮廓，$ΔP$的几何差异。在11个黑子上平均，我们找到了$ b_ \ perp = 1787 \ pm100 $ gauss的值。 $ b_ \ perp = b_ \ perp^{\ rm const} $的轮廓和在强度图中计算出的轮廓从视觉检查匹配，几何距离$ΔP$被发现在2个像素的顺序上。此外，对于$ b_ \ perp $，沿umbra-penumbra轮廓的不同数据集之间的标准偏差要小于$ b_ \ parallel $的标准偏差。我们的结果为Jurcak标准提供了进一步的支持，并存在不变的值$ b_ \ perp^{\ rm const} $在umbra-penumbra边界处。我们还发现，强度轮廓和轮廓之间的几何差异$ΔP$在$ b_ \ perp = b_ \ perp^{\ rm const} $中充当稳定性的索引。
The vertical component of the magnetic field ($B_\perp$) was found to reach a constant value at the umbra-penumbra boundary of stable sunspots in a recent statistical study of Hinode/SP data. The objective of this work is to verify the existence of a constant value for $B_\perp$ at the umbra-penumbra boundary from ground-based data in the near-infrared wavelengths and to determine its value for GREGOR Infrared Spectrograph (GRIS) data. This is the first statistical study on the Jurcak criterion with ground-based data, and we compare it with the results from Hinode and HMI data. Eleven spectropolarimetric data sets from the GRIS slit-spectograph containing stable sunspots were selected from the GRIS archive (sdc.leibniz-kis.de). SIR inversions including a polarimetric straylight correction are used to produce maps of the magnetic field vector using the Fe 1564.8 and 1566.2 nm lines. Averages of $B_\perp$ along umbra-penumbra boundaries are analyzed for the 11 data sets. Geometric differences between contours at the resulting $B_\perp^{\rm const}$ value and contours in intensity, $ΔP$, are calculated. Averaged over the 11 sunspots, we find a value of $B_\perp=1787\pm100$ gauss. Contours at $B_\perp=B_\perp^{\rm const}$ and contours calculated in intensity maps match from a visual inspection and the geometric distance $ΔP$ was found to be on the order of 2 pixels. Furthermore, the standard deviation between different data sets of averages along umbra--penumbra contours is smaller for $B_\perp$ than for $B_\parallel$ by a factor of 2.4. Our results provide further support to the Jurcak criterion with the existence of an invariable value $B_\perp^{\rm const}$ at the umbra--penumbra boundary. We also found that the geometric difference, $ΔP$, between intensity contours and contours at $B_\perp=B_\perp^{\rm const}$ acts as an index of stability for sunspots.
