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arXiv · 1402.7016

Helioseismic and Magnetic Imager observations of linear polarization from a loop prominence system

Pascal Saint-Hilaire·Jesper Schou·Juan-Carlos Martínez Oliveros·Hugh S. Hudson·Säm Krucker·Hazel Bain·Sébastien Couvidat
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Abstract

White-light observations by the Solar Dynamics Observatory's Helioseismic and Magnetic Imager of a loop-prominence system occurring in the aftermath of an X-class flare on 2013 May 13 near the eastern solar limb show a linearly polarized component, reaching up to $\sim$20% at an altitude of $\sim$33 Mm, about the maximal amount expected if the emission were due solely to Thomson scattering of photospheric light by the coronal material. The mass associated with the polarized component was 8.2$\times$10$^{14}$ g. At 15 Mm altitude, the brightest part of the loop was 3(+/-0.5)% linearly polarized, only about 20% of that expected from pure Thomson scattering, indicating the presence of an additional unpolarized component at wavelengths near Fe I (617.33 nm), probably thermal emission. We estimated the free electron density of the white-light loop system to possibly be as high as 1.8$\times$10$^{12}$ cm$^{-3}$.

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Pascal Saint-Hilaire, Jesper Schou, Juan-Carlos Martínez Oliveros, Hugh S. Hudson, Säm Krucker, Hazel Bain, Sébastien Couvidat. 2014-02-27. Helioseismic and Magnetic Imager observations of linear polarization from a loop prominence system. https://doi.org/10.1088/2041-8205/786/2/l19

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