全日面太阳矢量磁图不均匀性和磁饱和效应的研究

项目名称： 全日面太阳矢量磁图不均匀性和磁饱和效应的研究

项目编号： No.10878016

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 电工技术

项目作者： 苏江涛

作者单位： 中国科学院国家天文台

项目金额： 30万元

中文摘要： 怀柔全日面光学和磁场监测系统于2005 年12 月开始进行观测，磁场数据对全世界太阳物理学家公开，这对于研究太阳活动区之间的磁场拓扑的连通性、研究大尺度磁场的手征性分布、研究大尺度磁场非势性特征以及其与耀斑-日冕物质抛射之间的关系具有十分的重要意义。但是现在观测到的全日面偏振信号Q,U,V 在日面上分布有明显的不均匀性，我们已经从数据处理上成功解决了这个问题。下一步就是如何从仪器上找出造成这一现象的根本原因，然后加以修正。并且我们认为偏振信号的不均匀性和线偏振信号观测灵敏度低有直接原因。第二个问题就是向量磁像仪观测的太阳强磁场区发生的磁饱和效应。理论上，在远离谱线线心位置观测可以避免这个问题，但是日本Hinode 卫星线翼观测的纵场却出现了严重的磁饱和效应。这就意味着我们国家的空间太阳望远镜(SST) 在8 个通道观测磁场也可能遇到同样问题，所以有必要对这个问题进行提前研究。

中文关键词： 全日面矢量磁场；偏振信号不均匀性；灵敏度；磁饱和效应

英文摘要： The Solar Magnetism and Activity Telescope (SMAT) has been operational at Huairou Solar Observing Station (HSOS) since the end of 2005 and the data are open to all solar physicists in the world. However, there is a non-uniform pattern in full-disc vector magnetograms. We have solved this problem in off-line data reductions. The next step is to solve it from the optical instrument. Also we believe that the lower sensitivity of linear polarized signals is much associated with this non-uniform pattern. Another issue is the magnetic saturation in vector magnetograms taken with video vector magnetograph. In general, the polarized signal taken near the line center of a magnetic sensitive spectrum is affected most seriously while the signal in the line wings is relatively free of this effect. However, we find that both the Stokes V profile obtained at HSOS and the Stokes V image obtained with Hinode/SOT video magnetograph in the line wings are reduced seriously. This means that our SST project in 8-channel filter will confront the same problem. Therefore, it is nesessary to study the problem in advance.

英文关键词： Full-disk vector magnetic fields; nonuniformity;sensitivity; magnetic saturation