RAPID: Exploring the Dynamics and Thermodynamics of the Sun's Corona with Total Solar Eclipse Observations

点击翻译按钮获取中文摘要

This one-year RAPID project is aimed at improving present understanding of the dynamics and thermodynamics of the Sun's corona during total solar eclipses. Total solar eclipses continue to yield unique observing conditions, enabling an uninterrupted spatial coverage of coronal structures from the solar surface out to several solar radii. The main objective of this project is to build a state-of-the art instrument for solar eclipse observations that capitalizes on the unique diagnostic capabilities of coronal forbidden lines. These lines are best observed during total solar eclipses, and they are used to explore the dynamics and thermodynamics of the coronal plasmas within the first few solar radii above the solar surface, where the solar wind and coronal mass ejections originate and are accelerated. To achieve these science objectives, this project capitalizes on the pioneering insights achieved with the latest solar eclipse observations on 2017 Aug 21 of forbidden line emission, including imaging and spectroscopy. Knowledge gleaned from observations of the Sun's corona during the upcoming total solar eclipses on 2019 July 2 and 2020 December 14 will fill a much-needed gap in ongoing investigations of the physical processes controlling the coronal plasmas and magnetic fields. These observations will also impact the science programs to be executed by the future DKIST. The PI has been leading solar eclipse observations since 1995, and she will continue to engage and inspire women faculty, postdocs, graduate and undergraduate students, through their involvement with the unique scientific endeavors offered by the expeditions. The PI will present the results of the observations at conferences and will publish them in refereed journals. She will also share the knowledge with the general public through lectures, with emphasis on the magic of our closest star and its impact on our immediate environment. The research agenda of this RAPID project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research.The main objective of this one-year RAPID project is to build a state-of-the art instrument for solar eclipse observations that capitalizes on the unique diagnostic capabilities of coronal forbidden lines. Coronal forbidden lines are best observed during total solar eclipses, and they are used to explore the dynamics and thermodynamics of the coronal plasmas within the first few solar radii above the solar surface, where the solar wind and coronal mass ejections originate and are accelerated. Dominated by radiative excitation, emission from coronal forbidden lines in the visible and near infrared, as well as the continuum, can yield the chemical composition, temperature, density, non-thermal motions and outflows of the different constituents of the coronal plasma. Valuable insights into the dynamics and thermodynamics of the different manifestations of coronal heating processes can thus be gleaned. Recent eclipse discoveries have shown that the temperature of the outflowing plasma is dominated by 1,000,000 K, while emission from closed structures and the bulge of streamers, is at 2,000,000 K. They revealed that prominences, which are 100 times cooler and denser than the corona, are invariably enshrouded by the hottest material there, and directly linked to coronal structures, even when they erupt. Chromospheric material from prominences escapes, unaltered, with the hottest coronal material in CMEs.This project capitalizes on the pioneering insights achieved with the latest solar eclipse observations on 2017 Aug 21 of forbidden line emission, including imaging and spectroscopy. In this project, the team will build a state-of-the-art instrument that expands the wavelength coverage of the existing imaging suite of Fe IX, X, XI, XIII, and XIV emission lines by adding lines from different charge states of Ar, Ni and S. This enhances the diagnostic capabilities of the innovative imaging spectrometer to be built during this project by including the near UV and near IR wavelength ranges. The upcoming 2019 July 2 and 2020 December 14 total solar eclipses over Chile and Argentina offer an opportunity for coordinated multi-site observations, which has been successfully proven with the observations acquired during the 2017 August 21 total solar eclipse over the mainland U.S. Multi-site observations, with identical instrumentation, maximize data acquisition and enable studies of changes in coronal structures on time scales of tens of minutes.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.