Spectropolarimetric Insight into Plasma-Sheet Dynamics of a Solar Flare. (arXiv:1911.12666v1 [astro-ph.SR])

Spectropolarimetric Insight into Plasma-Sheet Dynamics of a Solar Flare. (arXiv:1911.12666v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+French_R/0/1/0/all/0/1">Ryan J. French</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Judge_P/0/1/0/all/0/1">Philip G. Judge</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matthews_S/0/1/0/all/0/1">Sarah A. Matthews</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Driel_Gesztelyi_L/0/1/0/all/0/1">Lidia van Driel-Gesztelyi</a>

We examine spectropolarimetric data from the CoMP instrument, acquired during
the evolution of the September 10th 2017 X8.2 solar flare on the western solar
limb. CoMP captured linearly polarized light from two emission lines of Fe XIII
at 1074.7 and 1079.8 nm, from 1.03 to 1.5 solar radii. We focus here on the hot
plasma-sheet lying above the bright flare loops and beneath the ejected CME.
The polarization has a striking and coherent spatial structure, with
unexpectedly small polarization aligned with the plasma-sheet. By elimination,
we find that small-scale magnetic field structure is needed to cause such
significant depolarization, and suggest that plasmoid formation during
reconnection (associated with the tearing mode instability) creates magnetic
structure on scales below instrument resolution of 6 Mm. We conclude that
polarization measurements with new coronagraphs, such as the upcoming DKIST,
will further enhance our understanding of magnetic reconnection and development
of turbulence in the solar corona.

We examine spectropolarimetric data from the CoMP instrument, acquired during
the evolution of the September 10th 2017 X8.2 solar flare on the western solar
limb. CoMP captured linearly polarized light from two emission lines of Fe XIII
at 1074.7 and 1079.8 nm, from 1.03 to 1.5 solar radii. We focus here on the hot
plasma-sheet lying above the bright flare loops and beneath the ejected CME.
The polarization has a striking and coherent spatial structure, with
unexpectedly small polarization aligned with the plasma-sheet. By elimination,
we find that small-scale magnetic field structure is needed to cause such
significant depolarization, and suggest that plasmoid formation during
reconnection (associated with the tearing mode instability) creates magnetic
structure on scales below instrument resolution of 6 Mm. We conclude that
polarization measurements with new coronagraphs, such as the upcoming DKIST,
will further enhance our understanding of magnetic reconnection and development
of turbulence in the solar corona.

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