太阳大气中氢原子的赖曼谱线  

Hydrogen Lyman Lines Emitted from the Solar Atmosphere

作　　者：田晖[1,3] 夏利东[2] 何建森 

机构地区：[1]北京大学地球与空间科学学院空间物理与应用技术研究所,北京100871 [2]山东大学威海分校空间科学与物理学院,威海264209 [3]马普协会太阳系研究所,德国37191

出　　处：《天文学进展》2010年第1期39-52,51-52+50,共14页Progress In Astronomy

基　　金：国家自然科学基金资助项目(40336053,40874090,40574064,40931055)

摘　　要：氢是太阳大气中最主要的元素。氢原子的赖曼(Lyman)谱线,尤其是赖曼阿尔法(Ly-α)谱线的辐射,是太阳色球和低过渡区能量损失的主要形式。在太阳的赖曼α像中,网络组织的辐射比较强,而辐射最强的地方是活动区。由于存在辐射转移效应,在宁静区,低阶赖曼谱线的谱形中央一般会形成一个凹陷,而在中央两侧则形成两个峰,两峰往往呈现出一定的不对称性。数值模拟和观测研究表明,赖曼谱线双峰的不对称性与高层大气中各种系统性流动有关。在太阳活动区,赖曼谱形在谱斑区与在宁静区类似;而在黑子区,赖曼谱形几乎没有中央凹陷。赖曼谱形也可用于诊断日珥、耀斑和日冕物质抛射等结构和现象的等离子体特性。该文回顾了赖曼谱线的观测历史,阐明了观测与模拟结果所揭示的物理过程,并结合笔者的认识进行了相应的评论。Hydrogen is the most abundant element in the solar atmosphere and its resonance lines, especially the Lyman-alpha （Ly-α） line, plays an important role in the overall radiative energy transport of the Sun. In this paper we review the observational and modeling results on the solar hydrogen Lyman line emissions The Ly-α line was used to observe the Sun since 1950s, when the era of space just began. It was found that the Ly-α emission is enhanced at lanes of the chromospheric network, and the brightest features in Ly-α images are active regions. However, so far no continuous Ly-α observation with both high spatial and temporal resolutions has been done. In the normal quiet Sun region, due to the effect of radiative transfer, the average lower-order Lyman line （Ly-α through Ly-α） profiles are found to be self-reversed at the centers and stronger in the red-horns. While the higher H Lyman series line （beyond Ly-α） profiles are flat-topped or even Gaussian-shaped. Recently, the Ly-α profiles were also obtained with the SUMER （Solar Ultraviolet Measurements of Emitted Radiation） instrument in high spectral, temporal,and spatial resolutions. It turns out that most Ly-α profiles are strongly reversed and stronger in the blue horns. It is believed that the opposite asymmetries in the average profiles of Ly-α and higher Lyman lines are probably caused by the combined effect of flows in the different layers of the solar atmosphere and opacity differences of the lines. A mechanism for line formation can not be simply imagined but must be thoroughly devised and further investigated with the help of models. In active regions, Lyman line profiles, especially Ly-α and Ly-α profiles, were obtained from early rocket observations and found to be similar to those in the quiet Sun. However, profiles obtained in these early observations suffered from geocoronal absorption. SUMER observations avoided this problem and revealed that the Lyman line profiles in sunspots show properties different from the aver

关 键 词：太阳过渡区 色球 紫外辐射 

分 类 号：P182.3[天文地球—天文学]