论文标题
来自HINODE/EIS和IRIS观察到的Fe XII线的太阳活性区域中非Maxwellian电子分布的诊断
Diagnostics of non-Maxwellian electron distributions in solar active regions from Fe XII lines observed by Hinode/EIS and IRIS
论文作者
论文摘要
我们介绍了在磁盘和外部的活动区域中Fe XII线的联合Hinode/eis和虹膜观察结果。我们对EIS数据使用了改进的校准，发现观察到的比率192.4 A / 1349 A与Chianti预测的值和静态区域中的冠状近似值一致，但在所有活性区域观察结果中却不是一致的，在所有活动区域观察结果中，该比率通常低于预期的比例，高达两个因素。我们研究了可能影响该比率的许多物理机制，例如不透明度和凉爽材料的吸收。我们在EIS Fe XII 193和195 A线中发现了明显的不透明度，但在192.4 A线上却与以前的发现一致。由于我们不能排除H在盘中观察中的H和他II中可能吸收的EUV吸收，因此我们专注于这种吸收最小的LIMB观察结果。考虑到这些以及可能的非平衡效应之后，我们建议对观察到的低Fe XII 192.4 A / 1349的最可能的解释A比率是在活性区域中存在非Maxwellian电子分布。这与以前基于EIS和IRIS观察的发现一致。
We present joint Hinode/EIS and IRIS observations of Fe XII lines in active regions, both on-disk and off-limb. We use an improved calibration for the EIS data, and find that the 192.4 A / 1349 A observed ratio is consistent with the values predicted by CHIANTI and the coronal approximation in quiescent areas, but not in all active region observations, where the ratio is often lower than expected by up to a factor of about two. We investigate a number of physical mechanisms that could affect this ratio, such as opacity and absorption from cooler material. We find significant opacity in the EIS Fe XII 193 and 195 A lines, but not in the 192.4 A line, in agreement with previous findings. As we cannot rule out possible EUV absorption by H, He and He II in the on-disk observations, we focus on an off-limb observation where such absorption is minimal. After considering these, as well as possible non-equilibrium effects, we suggest that the most likely explanation for the observed low Fe XII 192.4 A / 1349 A ratio is the presence of non-Maxwellian electron distributions in the active regions. This is in agreement with previous findings based on EIS and IRIS observations independently.
