论文标题
在下部太阳大气中观察和鉴定扭转波的问题
Problems in Observation and Identification of Torsional Waves in the Lower Solar Atmosphere
论文作者
论文摘要
记录光谱线宽度的周期性变化是观察扭转alfvén波的主要方法。从理论上讲，该方法似乎有效，但是当应用于数据时，它需要许多警告。例如，这些观测值的幅度应随磁盘上位置的变化而变化，并且它们应与无强度振荡相关。我们分析了冠状孔和面部区域中线宽度的周期性非热变化的广泛观察材料：Hα，He I10830Å，CA II8542Å，BA II 4554Å。在大多数情况下，我们在相似的频率下检测到相关的强度振荡。此外，我们没有观察到中心依赖性。这要求讨论该方法的实际有效性以及有关光谱线宽度非热变化性质的替代解释。根据我们的观察结果，我们考虑将线条剖面宽扩大是一种必要但没有足够的手段，可以明确鉴定下较低的太阳大气中的扭转Alfvén波。
Registering periodic variations of spectral line widths serves as the main method for observing torsional Alfvén waves. Theoretically, the method seems valid, yet it entails a number of caveats when applied to data. For instance, the amplitudes of these observations should vary with changes of the location on the disk, and they should be associated with no intensity oscillations. We analyze extensive observational material of periodic non-thermal variations of line widths in coronal holes and facular regions in a number of spectral lines: Hα, He I 10830 Å, Ca II 8542 Å, Ba II 4554 Å. In most cases, we detected associated intensity oscillations at similar frequencies. Besides, we observed no centre-to-limb dependency. This calls for a discussion on the practical validity of the method and on the alternative explanations for the nature of non-thermal variations of spectral line widths. Based on our observations, we consider registering line profile broadening a necessary but not sufficient means for unambiguous identification of torsional Alfvén waves in the lower solar atmosphere.
