We report the results of polarimetric observations of the total solar eclipse of 21 August 2017 from Rexburg, Idaho (USA).We use three synchronized DSLR cameras with polarization filters oriented at 0, 60, and 120 to provide high-dynamic-range RGB polarization images of the corona and surrounding sky.We measure tangential coronal polarization and vertical sky polarization, both as expected. These observations provide detailed detections of polarization neutral points above and below the eclipsed Sun where the coronal polarization is canceled by the sky polarization.We name these special polarization neutral points afterMinnaert and Van de Hulst.
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A Chromatic Treatment of Linear Polarization in the Solar Corona at the 2023 Total Solar Eclipse
The broadband solar K-corona is linearly polarized due to Thomson scattering. Various strategies have been used to represent coronal polarization. Here, we present a new way to visualize the polarized corona, using observations from the 2023 April 20 total solar eclipse in Australia in support of the Citizen CATE 2024 project. We convert observations in the common four-polarizer orthogonal basis (0°, 45°, 90°, & 135°) to −60°, 0°, and +60° (
- NSF-PAR ID:
- 10473957
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- Research Notes of the AAS
- Volume:
- 7
- Issue:
- 11
- ISSN:
- 2515-5172
- Format(s):
- Medium: X Size: Article No. 241
- Size(s):
- ["Article No. 241"]
- Sponsoring Org:
- National Science Foundation
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Abstract The infrared solar spectrum contains a wealth of physical data about the Sun and is being explored using modern detectors and technology with new ground-based solar telescopes. One such instrument will be the ground-based Cryogenic Near-IR Spectro-Polarimeter of the Daniel K. Inouye Solar Telescope (DKIST), which will be capable of sensitive imaging of the faint infrared solar coronal spectra with full Stokes I, Q, U, and V polarization states. Highly ionized magnetic dipole emission lines have been observed in galaxies and the solar corona. Quantifying the accuracy of spectral inversion procedures requires a precise spectroscopic calibration of observations. A careful interpretation of the spectra around prominent magnetic dipole lines is essential for deriving physical parameters and particularly for quantifying the off-limb solar coronal observations from DKIST. In this work, we aim to provide an analysis of the spectral regions around the infrared coronal emission lines of Fe
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Abstract This letter capitalizes on a unique set of total solar eclipse observations acquired between 2006 and 2020 in white light, Fe
xi 789.2 nm (T fexi= 1.2 ± 0.1 MK), and Fexiv 530.3 nm (T fexiv= 1.8 ± 0.1 MK) emission complemented by in situ Fe charge state and proton speed measurements from Advanced Composition Explorer/SWEPAM-SWICS to identify the source regions of different solar wind streams. The eclipse observations reveal the ubiquity of open structures invariably associated with Fexi emission from Fe10+and hence a constant electron temperature,T c=T fexi, in the expanding corona. The in situ Fe charge states are found to cluster around Fe10+, independently of the 300–700 km s−1stream speeds, referred to as the continual solar wind. Thus, Fe10+yields the fiducial link between the continual solar wind and itsT fexisources at the Sun. While the spatial distribution of Fexiv emission from Fe13+associated with streamers changes throughout the solar cycle, the sporadic appearance of charge states >Fe11+in situ exhibits no cycle dependence regardless of speed. These latter streams are conjectured to be released from hot coronal plasmas at temperatures ≥T fexivwithin the bulge of streamers and from active regions, driven by the dynamic behavior of prominences magnetically linked to them. The discovery of continual streams of slow, intermediate, and fast solar wind characterized by the sameT fexiin the expanding corona places new constraints on the physical processes shaping the solar wind.
