AI 中文总结
该研究利用IRIS光谱观测，对太阳谱斑五个高度的MHD波进行研究，发现谱斑内主导周期不变，孔隙中线性下降；确定了不同高度截止周期；还得出谱线在孔隙、谱斑和宁静太阳中形成高度的变化情况。
AI 中文摘要
这项工作旨在利用界面区域成像光谱仪（IRIS）提供的光谱观测，研究从光球层到上层色球层五个不同高度的太阳谱斑中的磁流体动力学（MHD）波。发现谱斑内主导周期不变，而在孔隙中，主导周期从光球层到上层色球层从4.20分钟线性降至3.20分钟。此外，在太阳谱斑中，交叉小波分析表明2.0至6.0分钟的周期从光球层传播到上层色球层。超过6分钟的周期在光球层和中间色球层具有零/恒定相位差。因此，6.0分钟周期将被视为这些高度的截止周期。接下来，估计了太阳谱斑上方MHD波在光球层和色球层的传播速度。在不确定性范围内，太阳谱斑中的传播速度接近声速，因此这些波本质上是慢磁声波。最后，通过相位差分析发现，太阳谱斑中Mg ii k2r和Mg ii k3的形成高度被低估，而Mn i的形成高度被高估。在孔隙中，Mg ii k2r、Mg ii k3和Mn i的形成高度被高估。有趣的是，在宁静太阳（QS）中，Mn i和Fe i的形成高度几乎相同，Mg ii k3的形成高度也与Mg ii k2r的形成高度相似。总之，这项工作报告了一些重要发现，即（1）光球层和色球层之间五个不同高度的主导周期，（2）谱斑中光球层、中间色球层和上层色球层截止周期的估计，以及（3）这些谱线在孔隙、谱斑和QS中的形成高度变化。
英文摘要
This work aims to investigate magnetohydrodynamic (MHD) waves in solar plages at five distinct heights, spanning from photosphere to the upper chromosphere, using spectroscopic observations provided by Interface Region Imaging Spectrograph (IRIS). The dominant period is found to not change within the plages, while, in pores, the dominant period decreases linearly from 4.20 to 3.20 minutes from the photosphere to the upper chromosphere. Furthermore, in the solar plages, cross-wavelet analysis reveals that periods from 2.0 to 6.0 minutes propagate till the upper chromosphere from the photosphere. The periods beyond 6 minutes have a zero/constant phase difference in the photosphere and in the middle chromosphere. Thus, the 6.0-minute period would be considered the cutoff period at these heights. Next, the propagation speeds of MHD waves above solar plages are estimated in the photosphere and chromosphere. Within the limit of uncertainties, the propagation speed in solar plage is close to the sound speed; hence, the waves are slow magnetoacoustic in nature. Lastly, with the help of phase difference analysis, we found that formation heights of Mg ii k2r and Mg ii k3 are underestimated in solar plage, while the formation height of Mn i is overestimated. In case of pores, the formation heights of Mg ii k2r, Mg ii k3, and Mn i are overestimated. Interestingly, in the quiet-Sun (QS), the formation heights of Mn i and Fe i are nearly the same, and also the formation height of Mg ii k3 is similar to the formation height of Mg ii k2r. In conclusion, some important findings are reported in this work, namely, (1) dominant periods at five different heights between the photosphere and chromosphere, (2) estimation of cutoff periods in the photosphere, middle chromosphere, and the upper chromosphere in the plages, and (3) variations in the formation heights of these spectral lines in pore, plage, and QS.
Comments26 Pages, 16 figures, Accepted for Publication in Advances in Space Research Journal
