Development of a High-Speed and Full-Disk Polarimeter for Solar Synoptic Observations

来自太阳的日冕物质抛射（CME）是空间天气和太阳风暴的主要原因。这样的风暴会破坏卫星，扰乱无线电通信，造成电网停电。研究这些事件的起源需要对太阳进行天文观测，并测量太阳盘面上的偏振。传统的地面天文观测无法可靠地测量这种偏振，因为地球的大气层不时地发生变化。本计画将发展一种能有效冻结大气扰动的高速偏振测量系统。由此产生的偏振测量将使研究太阳磁场的管理日冕物质抛射。这个太阳偏振测量系统将产生广泛的科学影响。科学界非常需要全天在整个太阳盘面上高速拍摄全偏振图像。它们将通过增进对空间气象的了解而造福社会。加州州立大学北岭分校是一所合格的本科研究机构（RUI），也是一所少数民族服务机构。这里开发的仪器将作为一个长期平台，支持少数民族和其他学生在其早期科学生涯中的培训和研究。在CME事件之前，期间和之后确定太阳色球层中的磁场将有助于理解触发CME的条件以及喷射物质的磁场特性。该偏振测量系统将由一个直径至少为235 mm的望远镜、一个可调谐法布里-珀罗干涉仪、一个高速偏振计和一个sCMOS相机组成。它将提供一个覆盖整个太阳圆盘的大视场，并将使全天观测成为可能。该系统将提供H-α和He D3谱线的全偏振图像，以推断CME前体、连续性或整个活动区域的色球磁场。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Coronal Mass Ejections (CMEs) from the Sun are key causes of space weather and solar storms. Such storms can damage satellites, disrupt radio communications and create blackouts of electricity power grids. Studying the origins of these events requires astronomical observations of the Sun, and measurements of polarization across the solar disk. Conventional ground-based astronomical observations cannot reliably measure such polarizations because the atmosphere of the Earth changes from time to time. This project will develop a novel high-speed polarimetry system that effectively freezes the atmospheric perturbations. Resulting polarization measurements will enable studying the solar magnetic fields that govern CMEs. This solar polarimetry system will have a broad scientific impact. Full polarization images at high-speed over the full solar disk on an all-day basis are highly needed by the scientific community. They will benefit society by enabling improved understanding of space weather. California State University, Northridge is an eligible Research in Undergraduate Institution (RUI) as well as a minority serving institution. The instrument developed here will serve as a long-term platform to support the training and research of minority and other students in their early scientific careers.Solar CMEs are often associated with pre-existing prominences. The determination of the magnetic field in the solar chromosphere before, during, and after a CME event will enable understanding the conditions that trigger CMEs, and the magnetic field properties of the ejected material. This polarimetry system will consist of a telescope with a diameter at least 235mm, a tunable Fabry-Perot interferometer, a high-speed polarimeter, and a sCMOS camera. It will provide a large field of view that covers the entire solar disk and it will enable all-day observations. This system will provide the full polarization images in the H-alpha and He D3 lines to infer the chromospheric magnetic field in CME precursors, prominences, or whole active regions.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.