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RUI: Multi-wavelength Spectroscopic and Spectropolarimetric Diagnostics of the Solar Atmosphere

RUI：太阳大气的多波长光谱和分光偏振诊断

基本信息

批准号：
2050340
负责人：
Debi Prasad Choudhary
金额：
$ 38.88万
依托单位：
The University Corporation, Northridge
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-04-15 至 2025-03-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2050340&HistoricalAwards=false
关键词：
RUI Multi wavelength Spectroscopic Spectropolarimetric

项目摘要

This 3-year project aims to develop data analysis techniques to infer the thermodynamic and magnetic structure of the solar atmosphere from the photosphere to a height of about 2-5 Mm using simultaneous multi-wavelength observations of spectral lines formed at different heights. Many current analysis approaches yield only simplified results instead of stratifications of physical properties. The project will develop an automatic, semi-empirical method to convert such results of lower complexity to atmospheric stratifications wherever they cannot be directly derived from an inversion of spectra. The method will be tested on observations of sunspots, where additional constraints on the magnetic field topology, connectivity and the gas density are available from the well-organized spatial structuring and magnetic field extrapolations. The results will enable one to address nearly all currently open questions in relation to the lower solar atmosphere, e.g., understanding the fine-structure and the properties of mass flows and oscillations inside sunspots from deep in the photosphere to the chromosphere. This will add to our understanding of the basic properties of sunspots, which are some of the most enigmatic objects in astrophysics. Sunspots are an integral part of late-type stars, play a vital role in stellar evolution and can influence life-supporting exoplanets including the Earth through space weather events that are rooted in sunspots and the active regions that host them. The method to infer the thermodynamic and magnetic structure of the solar atmosphere will be based on a piece-wise analysis of different photospheric and chromospheric spectral lines with already available inversion codes and the additional tools developed during the project. For any spectral line where current analysis methods do not provide stratifications of physical parameters of the solar atmosphere, e.g., the prominent chromospheric spectral line of neutral Hydrogen Alpha at 656 nm, a semi-empirical method using external constraints from magnetic field extrapolations will be employed to convert the results retrieved from a simplified modeling of the radiative transfer to stratifications. A major effort will be to consistently convert and combine the stratifications from different height regimes into a single atmospheric stratification of all relevant thermodynamic and magnetic parameters from 0 to about 5 Mm in the solar atmosphere. The resulting atmospheric model is expected to be in hydrostatic equilibrium, to provide all physical parameters on a geometrical height scale and to reproduce all observed spectral lines when a spectral synthesis of the model atmosphere is executed. A successful demonstration of the reliability of the approach on sunspot observations, where additional constraints are available because of the spatial continuity of the magnetic field topology, will allow one to decide on its suitability for observations of arbitrary solar targets. Any scientific question that requires accurate physical properties of the lower solar atmosphere can potentially be addressed with the results of the analysis approach. The tool developed through this project will be freely available to the community of solar researchers and will help in fully exploiting the observations with the NSF’s 4-meter class Daniel K. Inouye Solar Telescope. The participation of underrepresented students at California State University Northridge to both analyze and visualize the high-resolution spectropolarimetric data will prepare a future generation of the scientific workforce in solar physics. The research and EPO agenda of this project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

这个为期三年的项目旨在开发数据分析技术，利用对不同高度形成的谱线的同时多波长观测来推断从光球层到约2-5毫米高度的太阳大气的热力学和磁结构。当前的许多分析方法只能产生简化的结果，而不是物理特性的分层。该项目将开发一种自动、半经验方法，将复杂性较低的结果转换为无法直接从光谱反演得出的大气分层结果。该方法将在太阳黑子的观测中进行测试，其中对磁场拓扑、连通性和气体密度的额外约束可以从组织良好的空间结构和磁场外推中获得。这些结果将使人们能够解决几乎所有目前与太阳低层大气有关的悬而未决的问题，例如，了解太阳黑子内部从光球层深处到色球层的质量流和振荡的精细结构和特性。这将增进我们对太阳黑子基本特性的理解，太阳黑子是天体物理学中最神秘的物体之一。太阳黑子是晚型恒星不可或缺的一部分，在恒星演化中发挥着至关重要的作用，并且可以通过植根于太阳黑子及其活动区域的空间天气事件影响包括地球在内的支持生命的系外行星。推断太阳大气热力学和磁结构的方法将基于对不同光球和色球谱线的分段分析，以及现有的反演代码和项目期间开发的附加工具。对于当前分析方法不提供太阳大气物理参数分层的任何谱线，例如，656 nm 处的中性氢 Alpha 的显着色球谱线，将采用使用磁场外推的外部约束的半经验方法，将从辐射传输的简化模型中检索到的结果转换为分层。一项主要工作是将太阳大气中从 0 到约 5 Mm 的所有相关热力学和磁参数一致地转换和组合不同高度范围的层结为单个大气层结。由此产生的大气模型预计将处于流体静力平衡状态，以提供几何高度尺度上的所有物理参数，并在执行模型大气的光谱合成时再现所有观测到的光谱线。成功证明该方法在太阳黑子观测中的可靠性（由于磁场拓扑的空间连续性而存在额外的约束）将允许人们决定其是否适合观测任意太阳目标。任何需要太阳低层大气的精确物理特性的科学问题都可以通过分析方法的结果得到解决。通过该项目开发的工具将免费提供给太阳能研究人员社区，并将有助于充分利用 NSF 4 米级 Daniel K. Inouye 太阳望远镜的观测结果。加州州立大学北岭分校代表性不足的学生参与分析和可视化高分辨率光谱偏振数据将为下一代太阳物理学科学队伍做好准备。该项目的研究和 EPO 议程支持 AGS 部门在发现、学习、多样性和跨学科研究方面的战略目标。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。