黑子旋转多波段观测研究及影响因素分析
Multi-Wavelength Observations of Sunspot Rotation and Analysis of Influencing Factors
-
摘要: 黑子是太阳表面磁场高度集中的区域, 多波段观测可提供有关黑子在不同大气层次的磁场或动力学信息, 有利于研究非势磁场位形的形成. 基于羲和卫星(Chinese H\alpha Solar Explorer, CHASE)在H\alpha窗口进行多波段观测的优势(空间对齐和时间相同), 4组具有亮桥结构的太阳黑子被用于分析其在光球层和色球层的旋转特性, 以黑子亮桥作为示踪体的同时, 关注了亮桥演化对旋转速度判断的影响. 主要结论是: (1) 4个样本分析均发现, 黑子旋转的角速度在线翼(与H\alpha线心之间的波长间隔\Delta \lambda = -0.8 Å)与连续谱波段(\Delta \lambda = -2.8 Å)是一致的, 且角速度处于大约 0.5\ (^\circ)/\rmh 到 2\ (^\circ)/\rmh 的范围内; (2)其中有3个样本显示, 黑子在线心波段(色球层)表现出比线翼更快的旋转速度, 速度差异 0.1\ (^\circ)/\rmh , 但包括亮桥形态和亮度在内的动力学演化会明显影响测量结果; (3)其中3个样本黑子具有沿着径向贯穿本影的亮桥结构, 分析显示一侧的亮桥在各个波段上显示出旋转速度随半径呈现“慢-快-慢”的特征, 而另外一侧则显示出速度随半径逐渐增加的趋势, 充分显示了黑子旋转的非刚性特征. 建议在进行多波段黑子旋转研究时, 应当特别关注不同波段中黑子演化对结果的影响.Abstract: Sunspots represent regions of highly concentrated magnetic fields on the solar surface. Multi-wavelength observations enable the acquisition of magnetic and dynamical information across different atmospheric layers, thereby facilitating investigations into the formation of non-potential magnetic field configurations. Based on observations from the Chinese H\alpha Solar Explorer (CHASE), which offers the advantage of multi wavelengths observations within the H\alpha spectral window (featuring spatial co-alignment and temporal simultaneity), four sunspots exhibiting light bridge structures were analyzed to investigate their rotational characteristics in both the photosphere and chromosphere. While employing the light bridges within sunspots as tracers, particular attention was paid to the influence of light bridge evolution on the determination of rotational velocities. Key findings include: (1) analysis of all four samples revealed that the angular velocity of sunspot rotation in the line wing (\Delta\lambda=-0.8 Å, \Delta\lambda is the wavelength interval between the H\alpha line core and other wavelengths) and continuum (\Delta\lambda=-2.8 Å) is consistent with angular velocities ranging approximately from 0.5\ (^\circ)/\rmh to 2\ (^\circ)/\rmh ; (2) three of the samples exhibited faster rotational velocities in the line core (chromosphere) compared to the line wing, with a velocity difference of 0.1\ (^\circ)/\rmh , however, dynamic evolution (e.g., morphology and brightness variations of light bridges) significantly influenced the measurements; (3) three sunspots featured radially penetrating light bridges traversing the umbra. Analysis demonstrated that one side of the light bridges displayed a rotational velocity profile characterized by “slow-fast-slow” variations with increasing radial distance across all wavelengths, while the opposite side exhibited a gradually increasing velocity trend, highlighting the non-rigid rotational nature of sunspots. It is critical to consider the effects of sunspot evolution across different spectral wavelengths for multi-band researches of sunspot rotation.
下载: