Collaborative Research: Polarimetric Imaging and Spectroscopy of the Corona from 500-1500nm during Total Solar Eclipses

合作研究：日全食期间 500-1500nm 日冕的偏振成像和光谱学

• 批准号: 0450149
• 负责人: Munir Nayfeh
• 金额: $ 8.31万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0450149&HistoricalAwards=false
• 关键词: Collaborative; Research; Polarimetric; Imaging; Spectroscopy

The proposed four-year project will take advantage of unique opportunities offered by the total solar eclipses of 29 March 2006 (Libya) and 1 August 2008 (China-Russia) for imaging and spectroscopy of polarized coronal emissions at wavelengths spanning the visible to the near infrared. Polarized emission is a characteristic of some of the strongest coronal emission lines, while polarized fluorescence is a property of nanometer size dust particles. The near infrared polarimetric observations carried out by the PI during the eclipse of 21 June 2001 led to the serendipitous discovery of the signature of nanometer size dust particles in the inner corona. These 2001 observations also pointed to the potential existence of a discrete spectrum resulting from the fluorescence of these dust grains, and their spectrum is likely to be embedded within the spectrum of coronal ionic lines. By observing the next eclipses, the PI plans to infer the direction of the coronal magnetic field at different stages of the solar cycle, uncover the spectrum of nanometer size dust grains in the inner corona, and establish the relationship between interplanetary dust grains and the coronal magnetic field. In addition to the observations from Libya and China-Russia, simultaneous and identical observations will be made with the coronagraph in Hawaii. All the coronal observations will be compared with polarimetric laboratory measurements of fluorescence from silicon nanoparticles, which can be synthesized into stable and reproducible discrete sizes that fluoresce in the blue, green, yellow, and infrared part of the spectrum, under non-resonant UV or resonant excitation of their emission bands. Knowledge of the direction of the coronal field is critical for establishing the fraction of the solar magnetic flux that escapes into interplanetary space carrying the solar wind with it. Embedded in the solar wind, the interplanetary magnetic field shapes the environment of planets and defines the heliosphere. While the field also shapes cometary tails, it is likely to be responsible for the distribution of dust particles in the corona that may come from the sublimation of sun-grazing comets. The proposed program opens a new research direction by exploring the coupled signature of the coronal magnetic field direction and the fluorescence spectrum from nanoparticle dust grains in the inner corona. This effort will complement the laboratory experiments on polarized fluorescence from silicon nanoparticles.

拟议的四年项目将利用2006年3月29日日全食(利比亚)和2008年8月1日日全食(中国-俄罗斯)提供的独特机会，对从可见光到近红外波段的偏振日冕辐射进行成像和光谱分析。偏振发射是一些最强的日冕发射线的特征，而偏振荧光是纳米级尘埃粒子的特征。PI在2001年6月21日日食期间进行的近红外偏振观测偶然发现了内冕中纳米尺度尘埃颗粒的特征。这些2001年的观测还指出，这些尘埃颗粒的荧光可能存在一个离散的光谱，它们的光谱可能嵌入日冕离子线的光谱中。通过观测下一次日食，PI计划推断太阳周期不同阶段的日冕磁场方向，揭示日冕内纳米尺度尘埃颗粒的光谱，并建立行星际尘埃颗粒与日冕磁场之间的关系。除了来自利比亚和中国-俄罗斯的观测外，夏威夷的日冕仪还将进行同步和相同的观测。所有的日冕观测都将与实验室对硅纳米颗粒荧光的偏振测量进行比较，硅纳米颗粒可以合成成稳定且可重复的离散尺寸，在其发射波段的非共振UV或共振激发下，在光谱的蓝、绿、黄和红外部分发出荧光。日冕场方向的知识对于确定逃逸到携带太阳风的行星际空间的太阳磁通量的比例至关重要。嵌入太阳风中的行星际磁场塑造了行星的环境，并定义了日光层。虽然这个磁场也塑造了彗尾，但它很可能是负责日冕中尘埃粒子的分布，这些尘埃粒子可能来自掠日彗星的升华。该方案通过探索日冕磁场方向和日冕内纳米尘埃颗粒荧光光谱的耦合特征，开辟了一个新的研究方向。这项工作将是对硅纳米颗粒偏振荧光的实验室实验的补充。