Sensitivity of spectral lines to temperature, velocity, and magnetic field
Sensitivity of spectral lines to temperature, velocity, and magnetic field
复制标题
谱线对温度、速度和磁场的敏感性
DOI：
10.1051/0004-6361:20052720
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发表时间：
2005
影响因子：
6.5
通讯作者：
J. C. D. T. Iniesta
中科院分区：
文献类型：
--
作者：
D. C. Solana;L. B. Rubio;J. C. D. T. Iniesta
本文对弱太阳光球线对温度、速度和磁场的敏感性进行了分析和数值研究。我们的研究是基于响应函数的概念（Landi degl'Innocenti & Landi degl'Innocenti 1977; Ruiz Cobo & del Toro Pesta 1994）。太阳光谱偏振测量中常用的谱线，如可见光中的Fe ~（2+）630.25 nm和红外线中的Fe ~（2+）1564.85 nm，被详细地检查为从参考安静太阳和太阳黑子模型中出现。我们开发了一个简单的唯象模型，能够描述任何给定的线，这些大气参数的响应。我们发现：（a）谱线对速度和磁场的灵敏度随强度和圆偏振分布的尖锐度而增加，（B）谱线对温度的灵敏度主要取决于源函数随温度的变化，波长越长，灵敏度越小;（c）对温度不敏感的谱线，如Fe_（1564.85）nm和Fe_（557.61）nm，其等效宽度的变化比对温度敏感性高的谱线，如Fe_（630.25）nm，要大。我们的模型提供的关系是通用的，可以用来决定哪条线更适合于测量给定的大气参数。这项研究的结果是具有实际意义的新仪器的设计和更好地利用现有的。
We present an analytical and numerical study of the sensitivity of weak solar photospheric lines to tempera- ture, velocity, and magnetic fields. Our investigation is based on the concept of response functions (Landi degl'Innocenti & Landi degl'Innocenti 1977; Ruiz Cobo & del Toro Iniesta 1994). Lines commonly used in solar spectropolarimetry, like Fe 630.25 nm in the visible and Fe 1564.85 nm in the infrared, are examined in detail as emerging from reference quiet Sun and sunspot models. We develop a simple phenomenological model capable of describing the response of any given line to these atmospheric parameters. We find that: (a) the sensitivity of the lines to velocity and magnetic fields increases with the sharpness of the intensity and circular polarization profiles; (b) the sensitivity to temperature is determined mainly by the variation of the source function with temperature, which is smaller at longer wavelengths; and (c) lines quoted to be insensitive to temperature, like Fe 1564.85 nm and Fe 557.61 nm, exhibit larger changes in equivalent width than lines presumed to have higher sensitivities to T ,s uch as Fe 630.25 nm. The relations provided by our model are universal and can be used to decide which line is better suited to measuring a given atmospheric parameter. The results of this study are of practical interest for the design of new instruments and for better exploitation of existing ones.